controlled synthesis of sustainable n-doped hollow core ... · controlled synthesis of sustainable...

Nano Res

1

Controlled synthesis of sustainable n-doped hollow

core mesoporous shell carbonaceous nanospheres

from biomass

Chuanlong Han, Shiping Wang, Jing Wang, Mingming Li, Jiang Deng, Haoran Li and Yong Wang()

Nano Res., Just Accepted Manuscript • DOI: 10.1007/s12274-014-0540-x

http://www.thenanoresearch.com on July 9, 2014

© Tsinghua University Press 2014

Just Accepted

This is a “Just Accepted” manuscript, which has been examined by the peer-review process and has been

accepted for publication. A “Just Accepted” manuscript is published online shortly after its acceptance,

which is prior to technical editing and formatting and author proofing. Tsinghua University Press (TUP)

provides “Just Accepted” as an optional and free service which allows authors to make their results available

to the research community as soon as possible after acceptance. After a manuscript has been technically

edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP

article. Please note that technical editing may introduce minor changes to the manuscript text and/or

graphics which may affect the content, and all legal disclaimers that apply to the journal pertain. In no event

shall TUP be held responsible for errors or consequences arising from the use of any information contained

in these “Just Accepted” manuscripts. To cite this manuscript please use its Digital Object Identifier (DOI® ),

which is identical for all formats of publication.

Nano Research

DOI 10.1007/s12274-014-0540-x

TABLE OF CONTENTS (TOC)

Controlled Synthesis of Sustainable N-doped Hollow

Core Mesoporous Shell Carbonaceous nanospheres

from Biomass

Chuanlong Han, Shiping Wang, Jing Wang, Mingming

Li, Jiang Deng, Haoran Li and Yong Wang*

Carbon Nano Materials Group, Center for Chemistry of

High-performance and Novel Materials, Department of

Chemistry, Zhejiang University, Hangzhou 310028, P. R.

China.

N-doped hollow core disordered mesoporous shell carbonaceous

nanospheres (HCDMSs) are synthesized from a sustainable biomass

(glucosamine hydrochloride). The obtained materials possess suitable

nitrogen contents (~6.7-4.4 wt %), high specific surface areas (770 m2

g-1), controlled size (~450-50 nm), and tunable shell thickness (~70-10

nm). To our excitement, these HCDMSs exhibited striking

electrocatalytic activity, which was free from the crossover effect, and

its long-term durability was superior to that of commercial Pt/C (20

wt%).

http://mypage.zju.edu.cn/chemwy

http://mypage.zju.edu.cn/chemwy



from biomass


Received: day month year

Revised: day month year

Accepted: day month year

(automatically inserted by the

publisher)

© Tsinghua University Press

and Springer-Verlag Berlin

Heidelberg 2014

KEYWORDS

n-doped,

biomass,

hollow nanospheres,

oxygen reduction reaction

ABSTRACT

Encompassing ecological and economic concerns, the utilization of biomass to

produce carbonaceous materials has attracted intensive research and industrial

interest. Using nitrogen containing precursors could realize an in situ and

homogeneous incorporation of nitrogen into the carbonaceous materials with a

controlled process. Herein, N-doped hollow core disordered mesoporous shell

carbonaceous nanospheres (HCDMSs) were synthesized from glucosamine

hydrochloride (GAH), an applicable carbohydrate-based derivative. The

obtained HCDMSs possessed controlled size (~450-50 nm) and shell thickness

(~70-10 nm), suitable nitrogen contents (~6.7-4.4 wt %), and BET surface areas

up to 770 m2 g-1. These materials show excellent electrocatalytic activity as

metal-free catalyst for the oxygen reduction reaction (ORR) in both alkaline and

acidic media. Specifically, the prepared HCDMS-1 exhibits a high

diffusion-limited current, superior durability, and wonderful immunity

towards methanol crossover and CO poisoning for ORR in alkaline solution,

compared with those of commercial 20 wt % Pt/C catalyst.

1 Introduction 1

2

The synthesis of hollow carbonaceous spheres 3

(HCSs) has attracted a lot of attention due to their 4

unique properties, such as high surface-to-volume 5

ratios, low density and excellent thermal and 6

chemical stability [1-6]. Therefore, HCSs are 7

promising materials with diverse applications such 8

as fuel cells [7-10], lithium-ion batteries [11-14], 9

capacitor [15], adsorbent [16], catalyst supports 10

[17-20] and so on. Many efforts have been devoted 11

to the synthesis of HCSs by a nanocasting approach 12

which is considered to be the most straightforward 13

Nano Research

DOI (automatically inserted by the publisher)

Research Article

| www.editorialmanager.com/nare/default.asp

2 Nano Res.

way to create hollow structure [21, 22]. In addition, 1

the hollow core mesoporous shell carbonaceous 2

spheres (HCMSs) or capsules with tailorable 3

diameter, shell thickness and surface properties are 4

novel and promising nanomaterials [23, 24]. The 5

HCMSs have bimodal pore systems of tunable 6

hollow macroscopic core and mesoporous shell. As 7

the hollow cavity can act as a nanoreactor and the 8

shell provides controlled release pathways for the 9

encapsulated substances and vast surface area for 10

reactions, they have a wide range of applications 11

[25]. 12

Carbon precursors have a pivotal effect on the 13

preparation and final physical and chemical 14

properties of the obtained carbonaceous materials 15

[19, 26, 27]. In most cases, the surface of the 16

template is incompatible with the carbon source. 17

Fortunately, this can be solved by selectively 18

functionalizing the surface of the template with 19

prospective functional groups or electrostatic 20

charges. Usually, the precursors are phenol 21

formaldehyde resin [28-31], polyaniline [32], 22

polyacrylonitrile [33, 34], styrene [35], acetonitrile 23

[36], benzene [37, 38] and ethylene [39], all of which 24

are easy to be coated on the surfaces of the 25

templates. In recent years, the utilization of biomass 26

to synthesize carbonaceous materials has attracted 27

much research and industrial interest because of the 28

ecological and economic concerns [40-44]. Glucose 29

[3, 45, 46], sucrose [47], fructose [48], starch [49], 30

furfural [50, 51], dopamine [19], and grass [52, 53] 31

have been used as renewable and inexpensive 32

carbon sources with suitable carbon yield. This is a 33

dramatic and exciting development in the 34

production of carbonaceous materials. However, 35

the majority of the resulted carbonaceous materials 36

are bulk carbon without functional atoms or groups 37

in the matrix or on the surface [54]. 38

It is well known that the nitrogen dopant can 39

improve the properties of bulk carbon, such as the 40

conductivity, oxidation stability, basicity and 41

catalytic activity [55-59]. Nitrogen-doping into 42

carbonaceous materials can be realized either in situ 43

doping during the synthesis or by post-treatment 44

after the synthesis. In fact, using nitrogen 45

containing precursors can achieve a homogeneous 46

incorporation of nitrogen into the bulk 47

carbonaceous materials via the in situ doping 48

method. Herein, we developed a straightforward 49

and versatile method to prepare N-doped hollow 50

core disordered mesoporous shell carbonaceous 51

nanospheres (HCDMSs) using cheap and easy 52

available carbohydrate-based derivative, i.e. 53

glucosamine hydrochloride (GAH) as both carbon 54

and nitrogen precursor. The approach produced 55

N-doped HCDMSs with high surface areas (770 m2 56

g-1), controlled size and shell thickness, and nice 57

degree of graphitization. Furthermore, these 58

functional materials exhibited practical applications 59

in catalysis and electrochemistry. Here, they served 60

as metal-free catalysts for the oxygen reduction 61

reaction (ORR) with excellent electrocatalytic 62

activity in both alkaline and acidic solution. 63

64

2 Experimental 65

66

2.1 Materials 67

68

Ammonium hydroxide (NH4OH, 25-28 wt%), 69

potassium hydroxide (KOH, AR), perchloric acid 70

(HClO4, AR), ethanol (AR) were used as received 71

from Sinopharm Chemical Reagent Co., Ltd. 72

Tetraethyl orthosilicate (TEOS, AR), 73

trimethoxy(octadecyl)silane(90%, C18-TMS), 74

D(+)-Glucosamine hydrochloride (GAH, ≥99%), 75

NH4HF2 (AR, >98.5%) were used as received from 76

Aladdin Chemistry Co., Ltd. Nafion 117 solution (5 77

wt%) was obtained from Aldrich Chemistry Co., 78

Ltd. 20 wt% Pt/C was used as received from Alfa 79

Aesar Chemistry Co., Ltd. All the chemicals were 80

used as delivered without further treatment. 81

82

2.2 Synthesis of solid core disordered 83

www.theNanoResearch.com∣www.Springer.com/journal/12274 | Nano Research

3 Nano Res.

mesoporous shell silica spheres (SCDMSs) 1

2

Typically, taking the synthesis of SCDMS-1 as an 3

example: Firstly, 3.14 ml of ammonia hydroxide was 4

added into a solution containing 74 ml of ethanol 5

and 10 ml of deionized water, and then the mixed 6

solution was stirred at 30 oC for 0.5 h. Secondly, 6 ml 7

of TEOS was added into the above-prepared 8

mixture quickly under vigorous stirring and the 9

reaction mixture was kept stirring for 1 h to yield 10

uniform silica spheres (Stöber silica sol [60]). Then, 11

a mixture of 2 ml C18-TMS and 5 ml TEOS was 12

added dropwise to the above solution with 13

magnetic stirring to create a thin mesoporous silica 14

shell around the dense silica core [61]. The mixed 15

solution was then kept at 30 oC for 1h without 16

stirring to promote the cohydrolysis and 17

condensation of the C18-TMS and TEOS on the silica 18

core. Finally, the nanostructured silica was 19

centrifuged, dried at 70 oC overnight and calcined at 20

550 oC for 6 h in air. 21

22

2.3 Synthesis of hollow core disordered 23

mesoporous shell carbonaceous nanospheres 24

(HCDMSs) 25

26

Taking the synthesis of HCDMS-1 as an example: 27

Firstly, a solution of SCDMS-1 (1.0 g) and GAH (1.0 28

g) was mixed together adequately and then dried at 29

60 oC under magnetic stirring. The mixture was then 30

transferred into a 25 ml-crucible which was placed 31

in 100 ml-Teflon-lined autoclave with 10 ml 32

deionized water inside. Hydrothermal 33

carbonization was performed in a standard 34

laboratory oven, heated at 180 oC for 24 h. Then, the 35

composite material was calcined to the desired 36

temperature over a ramp stage of 90 minutes (10 oC 37

min-1 for HCDMS-1) followed by an isothermal hold 38

period of 1 h in a Muffle furnace in N2 flow (400 39

mL/min). After it cooled down to room 40

temperature, loose black solid was gained. Then the 41

black solid was ground into black powder and 42

transferred into a plastic bottle, 40 g NH4HF2 and 43

160 g deionized water were also added into the 44

bottle. The mixtures were stirred for 48 hours at 45

room temperature. After filtering the solution, the 46

black solid residue was dried at 70 oC in an oven 47

overnight. The obtained SCDMSs and HCDMSs 48

were denoted as SCDMS-X and HCDMS-X 49

respectively, where X was a sample number that 50

represent the different diameters (Table S1 in the 51

Electronic Supplementary Material (ESM)). And 52

HCDMS-2 (3, 4, 5) was prepared with the same 53

process except different template SCDMS-2 (3, 4, 5). 54

55

2.4 Characterization: 56

57

SEM images were obtained on a Sirion-100 58

microscope. TEM studies were performed on a 59

Hitachi HT-7700 microscope. High-Solution TEM 60

(HRTEM), STEM-HAADF and STEM-EDX were 61

performed on Tecnai G2 F30 S-Twin at an 62

acceleration voltage of 300 kV. Powder X-ray 63

diffraction (XRD) patterns were measured on a 64

D/tex-Ultima TV wide angle X-ray diffractometer 65

equipped with Cu Kα radiation (1.54 Å). The X-ray 66

photoelectron spectra (XPS) were obtained by an 67

ESCALAB 250Xi spherical analyzer using an 68

aluminum node (Al 1486.6 eV) X-ray source. The 69

Raman spectra were collected on a Raman 70

spectrometer (JY, HR 800) using 514-nm laser. The 71

BET surfaces were determined by ASAP 2020 HD88, 72

BET equation was used to calculate the surface 73

areas and pore volume and samples were degassed 74

at 200 oC for 8 h until the residual pressure was less 75

than 10-4 Pa. The element analysis was carried out 76

on the Flash EA 1112, ThermoFinnigan. 77

78

2.5 Electrochemical characterization 79

80

Electrochemical measurements were performed 81

using a computer-controlled workstation (LK2005A, 82

China) with a typical three-electrode cell. Rotating 83

disk electrode (RDE) was used as working electrode, 84


4 Nano Res.

a platinum sheet as counter electrode and saturated 1

calomel electrode (SCE) as reference electrode. The 2

activity of the materials was evaluated by the CV 3

and LSV techniques. Fabrication of the working 4

electrode was done by pasting catalyst inks on a 5

glassy carbon electrode (5 mm in diameter, from 6

Pine). The carbon ink was formed by mixing 10 mg 7

of HCDMS catalyst, 50 µL 5 wt% Nafion solution 8

and 500 µL ethanol in a plastic vial under 9

ultra-sonication for 20 min. A 5 µL aliquot of the 10

carbon ink was dropped on the surface of the glassy 11

carbon electrode, yielding the final catalyst loading 12

of approximate 0.46 mg/cm2. For comparison, the 13

commercial 20 wt% Pt/C catalyst ink was dealt with 14

in the same method. All the experiments were 15

conducted at room temperature. 16

17

3 Results and discussion 18

19

The overall synthetic procedure was shown in Fig. 1. 20

In the synthesis, SCDMSs were applied as sacrificial 21

templates and GAH was used as the carbon source 22

and nitrogen source. The SiO2 solid core was 23

synthesized according to the Stöber method using 24

TEOS as the precursor. To obtain the mesoporous 25

silica shell, another batch of TEOS was added with 26

C18-TMS as a porogen and calcined at 550 oC. 27

Through the screening of various synthetic 28

conditions such as the amount of NH4OH, TEOS 29

and C18-TMS, the diameter and the thickness of 30

mesoporous silica shell can be controlled (Table S1 31

in the Electronic Supplementary Material (ESM)). 32

These monodisperse SCDMSs were then used as 33

templates to synthesize HCDMSs. Briefly, GAH 34

was adsorbed on the surface of the SCDMSs and 35

partly incorporated into the mesoporous silica shell 36

to gain GAH/silica hybrids during the water 37

evaporation process. Then the GAH/silica hybrids 38

were subsequently converted to polymer/silica 39

composites via the self-condensation and 40

polymerization of GAH at 180 oC during the HTC 41

procedure. The polymer/silica nanocomposites 42

obtained were then carbonized at elevated 43

temperature (900 oC) to convert the coated polymer 44

into carbonaceous materials, followed by washing 45

the carbon/silica composite in NH4HF2 to remove 46

the silica template to gain HCDMSs. The detailed 47

synthetic process was presented in the experimental 48

section. 49

50

Figure 1 Schematic illustration for the synthesis of HCDMSs. 51

52

The diameter and shell thickness of HCDMSs 53

were tailorable concurrently by tuning the synthesis 54

conditions, using hard template method. This 55

56

Figure 2 Characterization results of the HCDMSs with tunable 57

diameters and shell thicknesses. (A, C and E) SEM images of 58

HCDMS-1, HCDMS-2 and HCDMS-3; (B, D and F) TEM 59

images of HCDMS-1, HCDMS-2 and HCDMS-3, separately. 60


5 Nano Res.

method has been widely adopted since it is 1

straightforward to apply and has obvious 2

advantages for controlling the size, shape and 3

structure of the products. Here, uniform HCDMSs 4

with varying diameters of HCDMS-1 (450±40 nm), 5

HCDMS-2 (220±20 nm), and HCDMS-3 (45±12 nm) 6

were synthesized (Fig. 2 and Fig. S4). The diameters 7

of the HCDMSs were strongly related to the 8

diameters of the SCDMSs which could be controlled 9

by tailoring the concentration of NH4OH and the 10

amount of TEOS and C18-TMS together (Fig. S1 and 11

Table S1 in the ESM). And the shell thicknesses 12

were (70±7), (35±5), and (9±3) nm for HCDMS-1, 13

HCDMS-2, and HCDMS-3, separately. The shell 14

thickness of the HCDMSs was turned by adjusting 15

the amount of TEOS and C18-TMS. As presented in 16

Fig. 3, SCDMS-1, SCDMS-4, and SCDMS-5 were 17

synthesized with the same silica core size but 18

different mesoporous SiO2 shell thickness (80±10), 19

(60±7), and (40±5), accordingly. When using them 20

(SCDMS-1, SCDMS-4, and SCDMS-5) as the seeds, 21

three different HCDMSs (HCDMS-1, HCDMS-4, 22

and HCDMS-5) can be prepared with the same core 23

size, but with different shell thicknesses of (70±7), 24

(60±7), and (35±5) nm, respectively. Hence, the 25

synthesis of HCDMSs with controlled diameter and 26

shell thickness has been successfully exhibited. The 27

details of the local structure of HCDMSs were 28

conducted by High-resolution transmission electron 29

microscopy (HRTEM). 30

Fig. 3 (G, G1 and G2) depicted the HRTEM 31

images of the edge and central views of HCMDS-1. 32

HRTEM studies of hollow carbonaceous 33

nanosphere suggested that the carbonaceous 34

materials contained a disordered mesoporous 35

structure. The combination of the nitrogen sorption 36

(Fig. 5) and HRTEM results clearly revealed that the 37

HCDMS-1 possessed uniform and disordered pore 38

channels. To verify the structural and compositional 39

details of HCDMS-1, STEM-HAADF imaging and 40

STEM-XEDX mapping analysis were carried out 41

upon it (Fig. 4). In agreement with expectations, 42

43

Figure 3 Characterization results of the SCDMSs and 44

HCDMSs with tunable shell thickness. TEM images of (A) 45

SCDMS-1, (B) SCDMS-4, (C) SCDMS-5, (D) HCDMS-1, (E) 46

HCDMS-4 and (F) HCDMS-5. HRTEM images of (G, G1, G2) 47

HCDMS-1. 48

49

element mapping illustrated a homogeneous 50

distribution of nitrogen, carbon and oxygen 51

throughout the sample. 52

53

Figure 4 A representative STEM-HAADF image of HCDMS-1 54

particle and the corresponding STEM-XEDX maps of the C-Kα, 55

N-Kα, O-Kα signals. 56

57

Typical nitrogen adsorption/desorption isotherms 58

at 77 K for the SCDMSs and HCDMSs were 59

investigated (Fig. 5). The isotherms for all the 60

samples synthesized in this work exhibited the type 61

IV isotherm characteristic of mesoporous materials 62


6 Nano Res.

according to the IUPAC nomenclature. The BET 1

surface area, total pore volume and pore size for the 2

samples were listed (Table 1 and Table S2 in the 3

ESM). The synthesis procedure employed here 4

allowed HCDMSs, which retained the morphology 5

and size of the silica precursor, to be obtained. The 6

resulting pore size distribution of HCDMSs 7

calculated from the desorption branches of nitrogen 8

isotherms by the BJH method was consistent with 9

the size of SCDMSs (Fig. 5C and D). As the pore 10

size distribution was only weakly changed in the 11

carbonaceous materials, we could exclude a 12

homogeneous carbon “nanocoating” on the pore 13

walls. This is consistent with the TEM and 14

STEM-XEDX images discussed above, which 15

showed a wonderful incorporation of the 16

carbonaceous materials. 17

18

Figure 5 N2 adsorption/desorption isotherms of (A) SCDMS-1, 19

SCDMS-4 and SCDMS-5; (B) HCDMS-1, HCDMS-4 and 20

HCDMS-5. Corresponding desorption pore size distributions of 21

(C) SCDMS-1, SCDMS-4 and SCDMS-5; (D) HCDMS-1, 22

HCDMS-4 and HCDMS-5; (E) BET surface areas versus shell 23

thickness; (F) BET surface areas versus average pore diameter. 24

25

Furthermore, it is interesting to find that: An 26

increase of the carbonaceous shell thickness from 36 27

to 59 to 70 nm led to an increase of the total surface 28

area (calculated by the BET method) from 402 to 724 29

to 770 m2/g (HCDMS-5, HCDMS-4 and HCDMS-1), 30

accordingly (Fig. 5E). In addition, with a decrease of 31

desorption average pore diameter from 7.9 to 6.0 to 32

4.8 nm, the specific surface area increased from 402 33

to 724 to 770 m2/g (HCDMS-5, HCDMS-4 and 34

HCDMS-1), respectively (Fig. 5F). It could be 35

concluded as follows: on the one hand, the smaller 36

the pore sizes in the porous carbonaceous materials 37

were, the higher surface areas were; On the other 38

hand, the mesoporous distributed in the shell of 39

HCDMSs made the most contribution to the specific 40

surface areas. Although the cavity sizes of 41

HCDMS-1, HCDMS-2 and HCDMS-3 were different, 42

they also had the same trend (Fig. S3 in the ESM). 43

44

Table 1 Specific surface area and elemental composition of the 45

HCDMSs. 46

Sample SBET

(m2 g-1)

Pore Volume

(cm3 g-1)

Pore Size

(nm)a N (%)

HCDMS-1 770 1.18 4.8 6.0

HCDMS-2 382 0.89 7.0 4.4

HCDMS-3 195 0.62 14.6 4.9

HCDMS-4 724 1.33 6.0 6.7

HCDMS-5 402 0.90 7.9 4.9

a. BJH desorption average pore diameter 47

48

To assess the effective introduction of N atom in 49

the carbonaceous materials, elemental analysis (EA) 50

and X-ray photoelectron spectroscopy (XPS) were 51

carried out (Fig. 6 and Table 1 and Table S3 in the 52

ESM). As shown in Table 1, the nitrogen content 53

analyzed by EA could be varied from 4.4 wt% for 54

HCDMS-2 to 6.7 wt% for HCDMS-4. EA gives 55

analytical information on the bulk of the materials, 56

while XPS is an important chemical analytical tool 57

for the surface assessments, giving the chemical 58

composition of material surfaces with depth down 59


7 Nano Res.

to 1-10 nm. Additional information of N-doping 1

type was then provided by XPS. The high 2

resolution N1s spectrum could be deconvoluted into 3

four different signals with binding energies of 398.6, 4

400.1, 401.3, and 403.5 eV, corresponding to 5

pyridinic (N1), pyrrolic (N2), graphitic quaternary 6

nitrogen (N3), and pyridine-N-oxide groups (N4), 7

respectively (Fig. 6A). For HCDMS-1, graphitic 8

quaternary nitrogen (48.3 %) and pyridinic nitrogen 9

(27.3 %) species were pronounced, indicating that 10

nitrogen was dominantly incorporated into the 11

graphitic structure. The bonding, graphitic order 12

and crystallinity of HCDMS-1 were studied by 13

Raman spectroscopy (Fig. 6B) and powder XRD (Fig. 14

S2 in the ESM). The G band at ~1590 cm-1 indicated 15

the in-plane vibration of sp2 carbon atoms including 16

C-C and N-C, while the D band at ~1350 cm-1 was 17

associated with the sp3 defect sites and a 18

defect-induced Raman feature, representing the 19

nonperfect crystalline structure of the material. The 20

graphitized nature of this sample was also 21

confirmed by XRD analysis. XRD peaks observed at 22

2 Theta of ~ 25O and 45O could be identified as (002) 23

and (101) reflections of a well-developed graphitic 24

carbon. From elemental analysis, powder XRD and 25

HRTEM, it could be deduced that the materials 26

produced by thermal condensation of GAH 27

featured a graphitic structure even when 28

carbonized at moderate temperatures, while a 29

reasonably proper amount of nitrogen was 30

incorporated in the structures. 31

32

Figure 6 (A) and (B) XPS curve and Raman spectrum of 33

HCDMS-1, respectively. 34

35

As discussed above, the HCDMSs fabricated from 36

the GAH precursor with a metal-free process, 37

which enabled a correlation between their structure 38

characteristics and electrochemical activity. The 39

electrocatalytic properties of the HCDMSs for ORR 40

were then evaluated by cyclic voltammetry (CV) 41

and linear sweep voltammetry (LSV) using a 42

standard three-electrode configuration. CV curves 43

of HCDMSs were carried out in 0.1 M KOH 44

solution saturated with oxygen at a scan rate of 50 45

mV s-1 (Fig. 7 A, B). The reduction current appeared 46

as a well-defined cathodic peak, which suggested 47

obvious electrocatalytic activity for oxygen 48

reduction. To gain further insight into the ORR 49

activity of HCDMSs, the reaction kinetics was 50

studied by rotating-disk voltammetry. As shown in 51

Fig. 7C, the onset potential of HCDMS-4 was more 52

positive than HCDMS-1 and HCDMS-5. The shell 53

thickness and average pore diameter of HCDMS-4 54

are both middle among them, which suggested that 55

moderate shell thickness and average pore diameter 56

were favorable factors for ORR performance of 57

HCDMSs with close nitrogen contents. In addition, 58

the onset potential and plateau current increased 59

from HCDMS-3 to HCDMS-2 to HCDMS-1 (Fig. 7D), 60

that was in accordance with the BET specific area 61

(195, 382 and 770 m2 g-1) and pore volume (0.62, 0.89 62

and 1.18 cm-3 g-1). Current density-potential curve of 63

HCDMS-1 was shown (Fig. 7E) and the current 64

density exhibited the typical increase with rotation 65

rate due to the shorted diffusion layer. The electron 66

transfer number (n) was analyzed on the basis of 67

Koutecky-Levich (KL) equations, a significant 68

increase could be observed with HCDMS-3 (n=2.9), 69

HCDMS-2 (n=3.8) and HCDMS-1 (n=4.0). 70

Furthermore, the durability, the methanol crossover 71

effect, and CO poisoning were investigated to 72

evaluate the properties of the HCDMSs (Fig. S5 in 73

the ESM). HCDMS-1 showed a better durability 74

with relative current of 79.2% than commercial Pt/C 75

with 70.8%. No obvious response for HCDMS-1 was 76

detected at 1000 s while methanol was added very 77

quickly, whereas a strong response was observed 78


8 Nano Res.

for the Pt/C catalyst at the same condition. As 1

shown in Figure. S5 c, the HCDMS electrode was 2

insensitive to CO, whereas the Pt/C electrode was 3

rapidly poisoned under the same conditions. 4

We also investigated the electrocatalytic 5

properties of the nitrogen-doped hollow 6

carbonaceous nanospheres for oxygen reduction in 7

acid electrolyte. As shown in Fig. S6 (in the ESM), 8

the polarization curves for ORR in O2-saturated 0.1 9

M HClO4 on HCDMS-1 and commercial Pt/C 10

catalysts. HCDMS-1 exhibited high catalytic activity 11

toward ORR, with an onset potential at 0.723 V (vs. 12

SCE) and a 0.2 V overpotential as compared with 13

Pt/C. The higher overpotential in acid medium 14

supported the previous view that ORR activities of 15

nitrogen-doped carbon were higher in alkaline 16

medium than in acid medium [62]. 17

Figure 7 Cyclic voltammograms of (A) HCDMS-1, HCDMS-4 18

and HCDMS-5; (B) HCDMS-1, HCDMS-2 and HCDMS-3. 19

Linear sweep voltammograms on a glassy carbon rotating disk 20

electrode in O2-saturated 0.1 M KOH at a rotation rate of 1600 21

rpm (C) HCDMS-1, HCDMS-4 and HCDMS-5; (D) HCDMS-1, 22

HCDMS-2 and HCDMS-3; (E) LSV curves of ORR at various 23

rotation speeds at HCDMS-1 electrode; (F) Koutecky-Levich 24

plots for HCDMS-1, HCDMS-2, HCDMS-3 and 20 wt% Pt/C 25

at -0.60V. 26

27

4 Conclusion 28

29

In summary, we have demonstrated an easy and 30

effective route to synthesize N-doped HCDMSs 31

using carbohydrate-based derivative, i.e. GAH as 32

both carbon and nitrogen source. The approach 33

yielded N-doped HCDMSs with high surface areas 34

(770 m2 g-1), tailorable size and shell thickness, and 35

appropriate nitrogen content. Because of all these 36

superb features mentioned above, they could serve 37

as efficiently metal-free catalyst for the oxygen 38

reduction reaction both in alkaline and acidic 39

solutions. Importantly, we have presented a 40

cost-effective synthesis towards N-doped HCDMSs 41

based on sustainable biomass. Furthermore, the 42

HCDMSs show great promise for many 43

applications such as lithium ion batteries, 44

adsorbents, catalyst supports and drug delivery 45

carriers, and more works focusing on these aspects 46

are ongoing. 47

48

Acknowledgements 49

50

Financial support from the National Natural Science 51

Foundation of China (U1162124& 21376208), the 52

Zhejiang Provincial Natural Science Foundation for 53

Distinguished Young Scholars of China 54

(LR13B030001), the Specialized Research Fund for 55

the Doctoral Program of Higher Education 56

(J20130060), the Fundamental Research Funds for 57

the Central Universities, the Program for Zhejiang 58

Leading Team of S&T Innovation, the Partner 59

Group Program of the Zhejiang University and the 60

Max-Planck Society are greatly appreciated. 61

62

Electronic Supplementary Material: 63

Supplementary material (TEM and SEM images, 64

Powder XRD analysis of HCDMS-1, N2 65

adsorption/desorption isotherms, Current-time 66

response, the synthesis conditions and physical 67


9 Nano Res.

properties, structural properties and elemental 1

analysis data) is available in the online version of 2

this article at 3

http://dx.doi.org/10.1007/s12274-***-****-* 4

5

References 6

7

1] Sun, X.; Li, Y. Colloidal carbon spheres and their core/shell structures 8

with noble-metal nanoparticles. Angew. Chem. Int. Ed. 2004, 43, 597-601. 9

2] Lu, A. H.; Li, W. C.; Hao, G. P.; Spliethoff, B.; Bongard, H. J.; Schaack, 10

B. B.; Schuth, F. Easy synthesis of hollow polymer, carbon, and graphitized 11

microspheres. Angew. Chem. Int. Ed. 2010, 49, 1615-1618. 12

3] White, R. J.; Tauer, K.; Antonietti, M.; Titirici, M. M. Functional hollow 13

carbon nanospheres by latex templating. J. Am. Chem. Soc. 2010, 132, 14

17360-17363. 15

4] Lei, Z. B.; Chen, Z. W.; Zhao, X. S. Growth of polyaniline on hollow 16

carbon spheres for enhancing electrocapacitance. J. Phys. Chem. C. 2010, 114, 17

19867–19874. 18

5] Guo, L.; Zhang, J.; He, Q.; Zhang, L.; Zhao, J.; Zhu, Z.; Wu, W.; Shi, J. 19

Preparation of millimetre-sized mesoporous carbon spheres as an effective 20

bilirubin adsorbent and their blood compatibility. Chem. Commun. 2010, 46, 21

7127-7129. 22

6] Lai, X.; Halpert, J. E.; Wang, D. Recent advances in 23

micro-/nano-structured hollow spheres for energy applications: From simple to 24

complex systems. Energy Environ. Sci. 2012, 5, 5604-5618. 25

7] Schaefer, Z. L.; Gross, M. L.; Hickner, M. A.; Schaak, R. E. Uniform 26

hollow carbon shells: Nanostructured graphitic supports for improved 27

oxygen-reduction catalysis. Angew. Chem. Int. Ed. 2010, 49, 7045-7048. 28

8] Kim, J. H.; Yu, J. S. Erythrocyte-like hollow carbon capsules and their 29

application in proton exchange membrane fuel cells. Phys. Chem. Chem. Phys. 30

2010, 12 15301-15308. 31

9] Fang, B. Z.; Kim, J. H.; Lee, C.; Yu, J. S. Hollow macroporous 32

core/mesoporous shell carbon with a tailored structure as a cathode electrocatalyst 33

support for proton exchange membrane fuel cells. J. Phys. Chem. C. 2008, 112, 34

639-645. 35

10] Yan, Z.; Meng, H.; Shen, P. K.; Meng, Y.; Ji, H. Effect of the templates 36

on the synthesis of hollow carbon materials as electrocatalyst supports for direct 37

alcohol fuel cells. Int. J. Hydrogen Energy. 2012, 37, 4728-4736. 38

11] Jayaprakash, N.; Shen, J.; Moganty, S. S.; Corona, A.; Archer, L. A. 39

Porous hollow carbon@sulfur composites for high-power lithium-sulfur batteries. 40

Angew. Chem. Int. Ed. 2011, 50, 5904-5908. 41

12] Yang, S.; Feng, X.; Zhi, L.; Cao, Q.; Maier, J.; Mullen, K. 42

Nanographene-constructed hollow carbon spheres and their favorable 43

electroactivity with respect to lithium storage. Adv. Mater. 2010, 22, 838-842. 44

13] Zhang, W. M.; Hu, J. S.; Guo, Y. G.; Zheng, S. F.; Zhong, L. S.; Song, W. 45

G.; Wan, L. J. Tin-nanoparticles encapsulated in elastic hollow carbon spheres for 46

high-performance anode material in lithium-ion batteries. Adv. Mater. 2008, 20, 47

1160-1165. 48

14] Zhang, K.; Zhao, Q.; Tao, Z. L.; Chen, J. Composite of sulfur 49

impregnated in porous hollow carbon spheres as the cathode of li-s batteries with 50

high performance. Nano Res. 2012, 6, 38-46. 51

15] Han, Y.; Dong, X.; Zhang, C.; Liu, S. Hierarchical porous carbon 52

hollow-spheres as a high performance electrical double-layer capacitor material. J. 53

Power Sources. 2012, 211, 92-96. 54

16] Guo, L.; Zhang, L.; Zhang, J.; Zhou, J.; He, Q.; Zeng, S.; Cui, X.; Shi, J. 55

Hollow mesoporous carbon spheres--an excellent bilirubin adsorbent. Chem. 56

Commun. 2009, 6071-6073. 57

17] Harada, T.; Ikeda, S.; Ng, Y. H.; Sakata, T.; Mori, H.; Torimoto, T.; 58

Matsumura, M. Rhodium nanoparticle encapsulated in a porous carbon shell as an 59

active heterogeneous catalyst for aromatic hydrogenation. Adv. Funct. Mater. 60

2008, 18, 2190-2196. 61

18] Zeng, Y.; Wang, X.; Wang, H.; Dong, Y.; Ma, Y.; Yao, J. Multi-shelled 62

titania hollow spheres fabricated by a hard template strategy: Enhanced 63

photocatalytic activity. Chem. Commun. 2010, 46, 4312-4314. 64

19] Liu, R.; Mahurin, S. M.; Li, C.; Unocic, R. R.; Idrobo, J. C.; Gao, H.; 65

Pennycook, S. J.; Dai, S. Dopamine as a carbon source: The controlled synthesis 66

http://dx.doi.org/10.1007/s12274-***-****-*


10 Nano Res.

of hollow carbon spheres and yolk-structured carbon nanocomposites. Angew. 1

Chem. Int. Ed. 2011, 50, 6799-6802. 2

20] Fuertes, A. B.; Sevilla, M.; Valdes-Solis, T.; Tartaj, P. Synthetic route to 3

nanocomposites made up of inorganic nanoparticles confined within a hollow 4

mesoporous carbon shell. Chem. Mater. 2007, 19, 5418-5423. 5

21] Xia, Y.; Mokaya, R. Ordered mesoporous carbon hollow spheres 6

nanocast using mesoporous silica via chemical vapor deposition. Adv. mater. 2004, 7

16, 886-891. 8

22] Lou, X. W.; Deng, D.; Lee, J. Y.; Archer, L. A. Preparation of sno2 9

carbon composite hollow spheres and their lithium storage properties. Chem. 10

Mater. 2008, 20, 6562-6566. 11

23] Yoon, S. B.; Sohn, K.; Kim, J. Y.; Shin, C. H.; Yu, J. S.; Hyeon, T. 12

Fabrication of carbon capsules with hollow macroporous core/mesoporous shell 13

structures. Adv. Mater. 2002, 14, 19-21. 14

24] Valle-Vigon, P.; Sevilla, M.; Fuertes, A. B. Synthesis of uniform 15

mesoporous carbon capsules by carbonization of organosilica nanospheres. Chem. 16

Mater. 2010, 22, 2526-2533. 17

25] Lu, A. H.; Hao, G. P.; Sun, Q.; Zhang, X. Q.; Li, W. C. Chemical 18

synthesis of carbon materials with intriguing nanostructure and morphology. 19

Macromol. Chem. Phys. 2012, 213, 1107-1131. 20

26] Li, S. Y.; Liang, Y. R.; Wu, D. C.; Fu, R. W. Fabrication of bimodal 21

mesoporous carbons from petroleum pitch by a one-step nanocasting method. 22

Carbon. 2010, 48, 839-843. 23

27] Soll, S.; Fellinger, T. P.; Wang, X.; Zhao, Q.; Antonietti, M.; Yuan, J. 24

Water dispersible, highly graphitic and nitrogen-doped carbon nanobubbles. Small. 25

2013, 9, 4135-4141. 26

28] Lu, A. H.; Sun, T.; Li, W. C.; Sun, Q.; Han, F.; Liu, D. H.; Guo, Y. 27

Synthesis of discrete and dispersible hollow carbon nanospheres with high 28

uniformity by using confined nanospace pyrolysis. Angew. Chem. Int. Ed. 2011, 29

50, 11765-11768. 30

29] Yang, M.; Ma, J.; Ding, S. J.; Meng, Z. K.; Liu, J. G.; Zhao, T.; Mao, L. 31

Q.; Shi, Y.; Jin, X. G.; Lu, Y. F. et al. Phenolic resin and derived carbon hollow 32

spheres. Macromol. Chem. Phys. 2006, 207, 1633-1639. 33

30] Zakhidov, A. A.; Baughman, R. H.; Iqbal, Z.; Cui, C. X.; Khayrullin, I.; 34

Dantas, S. O.; Marti, J.; Ralchenko, V. G. Carbon structures with 35

three-dimensional periodicity at optical wavelengths. Science. 1998, 282, 36

897-901. 37

31] Sun, Z.; Liu, Y.; Li, B.; Wei, J.; Wang, M.; Yue, Q.; Deng, Y.; Kaliaguine, 38

S.; Zhao, D. Y. General synthesis of discrete mesoporous carbon microspheres 39

through a confined self-assembly process in inverse opals. . ACSNANO. 2013, 7, 40

8706-8714. 41

32] Yang, M.; Ma, J.; Zhang, C.; Yang, Z.; Lu, Y. General synthetic route 42

toward functional hollow spheres with double-shelled structures. Angew. Chem. 43

Int. Ed. 2005, 44, 6727-6730. 44

33] Tang, C.; Bombalski, L.; Kruk, M.; Jaroniec, M.; Matyjaszewski, K.; 45

Kowalewski, T. Nanoporous carbon films from “hairy” polyacrylonitrile-grafted 46

colloidal silica nanoparticles. Adv. Mater. 2008, 20, 1516-1522. 47

34] Kruk, M.; Dufour, B.; Celer, E. B.; Kowalewski, T.; Jaroniec, M.; 48

Matyjaszewski, K. Synthesis of mesoporous carbons using ordered and disordered 49

mesoporous silica templates and polyacrylonitrile as carbon precursor. J. Phys. 50

Chem. B. 2005, 109, 9216-9225. 51

35] Xia, Y. D.; Mokaya, R. Synthesis of ordered mesoporous carbon and 52

nitrogen-doped carbon materials with graphitic pore walls via a simple chemical 53

vapor deposition method. Adv. Mater. 2004, 16, 1553-1558. 54

36] Xia, Y. D.; Yang, Z. X.; Mokaya, R. Mesostructured hollow spheres of 55

graphitic n-doped carbon nanocast from spherical mesoporous silica. J. Phys. 56

Chem. B. 2004, 108, 19293-19298. 57

37] Su, F.; Zhao, X. S.; Wang, Y.; Wang, L.; Lee, J. Y. Hollow carbon 58

spheres with a controllable shell structure. J. Mater. Chem. 2006, 16, 4413-4419. 59

38] Wang, Y.; Su, F. B.; Lee, J. Y.; Zhao, X. S. Crystalline carbon hollow 60

spheres, crystalline carbon -sno2 hollow spheres, and crystalline sno2hollow 61

spheres: Synthesis and performance in reversible li-ion storage. Chem. Mater. 62

2006, 18, 1347-1353. 63

39] Chen, X.; Kierzek, K.; Jiang, Z.; Chen, H.; Tang, T.; Wojtoniszak, M.; 64


11 Nano Res.

Kalenczuk, R. J.; Chu, P. K.; Borowiak-Palen, E. Synthesis, growth mechanism, 1

and electrochemical properties of hollow mesoporous carbon spheres with 2

controlled diameter. J. Phys. Chem. C. 2011, 115, 17717-17724. 3

40] Brun, N.; Wohlgemuth, S. A.; Osiceanu, P.; Titirici, M. M. Original 4

design of nitrogen-doped carbon aerogels from sustainable precursors: 5

Application as metal-free oxygen reduction catalysts. Green Chem. 2013, 15, 6

2514-2524. 7

41] Hu, B.; Wang, K.; Wu, L.; Yu, S. H.; Antonietti, M.; Titirici, M. M. 8

Engineering carbon materials from the hydrothermal carbonization process of 9

biomass. Adv. Mater. 2010, 22, 813-828. 10

42] Zhang, P.; Gong, Y.; Li, H.; Chen, Z.; Wang, Y. Solvent-free aerobic 11

oxidation of hydrocarbons and alcohols with pd@n-doped carbon from glucose. 12

Nat. Commun. 2013, 4, 1593-1603. 13

43] Zhang, P.; Yuan, J.; Fellinger, T. P.; Antonietti, M.; Li, H.; Wang, Y. 14

Improving hydrothermal carbonization by using poly(ionic liquid)s. Angew. Chem. 15

Int. Ed. 2013, 52, 6028-6032. 16

44] Wang, J.; Xu, Z.; Gong, Y. T.; Han, C. L.; Li, H. R.; Wang, Y. One-step 17

production of sulfur and nitrogen co-doped graphitic carbon for oxygen reduction: 18

Activation effect of oxidized sulfur and nitrogen. ChemCatChem. 2014, 19

10.1002/cctc.201301102. 20

45] Sun, X.; Li, Y. Hollow carbonaceous capsules from glucose solution. J. 21

Colloid Interface Sci. 2005, 291, 7-12. 22

46] Ikeda, S.; Tachi, K.; Ng, Y. H.; Ikoma, Y.; Sakata, T.; Mori, H.; Harada, 23

T.; Matsumura, M. Selective adsorption of glucose-derived carbon precursor on 24

amino-functionalized porous silica for fabrication of hollow carbon spheres with 25

porous walls. Chem. Commun. 2007, 19, 4335-4340. 26

47] Hampsey, J. E.; Hu, Q.; Rice, L.; Pang, J.; Wu, Z.; Lu, Y. A general 27

approach towards hierarchical porous carbon particles. Chem. Commun. 2005, 28

3606-3608. 29

48] Kubo, S.; White, R. J.; Yoshizawa, N.; Antonietti, M.; M., T. M. Ordered 30

carbohydrate-derived porous carbons. Chem. Mater. 2011, 23, 4882-4885. 31

49] Cui, X.; Antonietti, M.; Yu, S. H. Structural effects of iron oxide 32

nanoparticles and iron ions on the hydrothermal carbonization of starch and rice 33

carbohydrates. Small. 2006, 2, 756-759. 34

50] Titirici, M. M.; Thomas, A.; Antonietti, M. Replication and coating of 35

silica templates by hydrothermal carbonization. Adv. Funct. Mater. 2007, 17, 36

1010-1018. 37

51] Kubo, S.; Tan, I.; White, R. J.; Antonietti, M.; Titirici, M. M. Template 38

synthesis of carbonaceous tubular nanostructures with tunable surface properties. 39

Chem. Mater. 2010, 22, 6590-6597. 40

52] Zhang, H.; Wang, Y.; Wang, D.; Li, Y.; Liu, X.; Liu, P.; Yang, H.; An, T.; 41

Tang, Z.; Zhao, H. Hydrothermal transformation of dried grass into graphitic 42

carbon-based high performance electrocatalyst for oxygen reduction reaction. 43

Small. 2014, DOI: 10.1002/smll.201400781. 44

53] Liu, S.; Tian, J.; Wang, L.; Zhang, Y.; Qin, X.; Luo, Y.; Asiri, A. M.; 45

Al-Youbi, A. O.; Sun, X. Hydrothermal treatment of grass: A low-cost, green 46

route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an 47

effective fluorescent sensing platform for label-free detection of cu(ii) ions. Adv. 48

Mater. 2012, 24, 2037-2041. 49

54] Wang, Y.; Wang, X.; Antonietti, M. Polymeric graphitic carbon nitride as 50

a heterogeneous organocatalyst: From photochemistry to multipurpose catalysis to 51

sustainable chemistry. Angew. Chem. Int. Ed. 2012, 51, 68-89. 52

55] Paraknowitsch, J. P.; Zhang, J.; Su, D.; Thomas, A.; Antonietti, M. Ionic 53

liquids as precursors for nitrogen-doped graphitic carbon. Adv. Mater. 2010, 22, 54

87. 55

56] Shao, Y. Y.; Sui, J. H.; Yin, G. P.; Gao, Y. Z. Nitrogen-doped carbon 56

nanostructures and their composites as catalytic materials for proton exchange 57

membrane fuel cell. Applied Catalysis B: Environmental. 2008, 79, 89-99. 58

57] Xu, X.; Li, Y.; Gong, Y.; Zhang, P.; Li, H.; Wang, Y. Nitrogen-bulk 59

carbon synthesis of palladium nanoparticles supported on mesoporous n-doped 60

carbon and their catalytic ability for biofuel upgrade. J. Am. Chem. Soc. 2012, 134, 61

16987-16990. 62

58] Han, C. L.; Wang, J.; Gong, Y. T.; Xu, X.; Li, H.; Wang, Y. 63

Nitrogen-doped hollow carbon hemispheres as efficient metal-free electrocatalysts 64

for oxygen reduction reaction in alkaline medium. J. Mater. Chem. A. 2014, 2, 65


12 Nano Res.

605-609. 1

59] Liu, Z. Y.; Zhang, G. X.; Lu, Z. Y.; Jin, X. Y.; Chang, Z.; Sun, X. M. 2

One-step scalable preparation of n-doped nanoporous carbon as a 3

high-performance electrocatalyst for the oxygen reduction reaction. Nano Res. 4

2013, 6, 293-301. 5

60] Stober, W.; Fink, A. Controlled growth of monodisperse silica 6

spheres in the micron size range. . J. Colloid Interface Sci. 1968, 26, 7

62-69. 8

61] Kim, J. H.; Yoon, S. B.; Kim, J. Y.; Chae, Y. B.; Yu, J. S. Synthesis of 9

monodisperse silica spheres with solid core and mesoporous shell: Morphological 10

control of mesopores. Colloids and Surfaces A: Physicochem. Eng. Aspects. 2008, 11

313-314, 77-81. 12

62] Yang, W.; Fellinger, T. P.; Antonietti, M. Efficient metal-free oxygen 13

reduction in alkaline medium on high-surface-area mesoporous nitrogen-doped 14

carbons made from ionic liquids and nucleobases. J. Am. Chem. Soc. 2011, 133, 15

206-209. 16

17


Nano Res.

Electronic Supplementary Material



from biomass


Supporting information to DOI 10.1007/s12274-****-****-*

Figure S1. TEM and SEM images of SCDMS-1, SCDMS-2 and SCDMS-3.

Figure S2. Powder X-ray diffraction patterns of the HCDMS-1.

Figure S3. N2 adsorption/desorption isotherms of SCDMSs and HCDMSs.

Figure S4. Diameter distribution of HCDMSs.

Figure S5. Chronoamperometric response for ORR at HCDMS-1 and Pt/C electrodes.

Figure S6. Polarization curves for oxygen reduction in O2-saturated 0.1 M HClO4 solution.

Figure S7. (A) Cyclic voltammogram and (B) Linear sweep voltammogram of SCDMS-1.

Table S1. The synthesis conditions and physical properties.

Table S2. Structural properties of the SCDMSs.

Table S3. Elemental analysis data obtained for HCDMSs.


Nano Res.

Figure S1. (A) (C) and (D) TEM images of SCDMS-1, SCDMS-2 and SCDMS-3,

respectively, (B) SEM image of SCDMS-1.

Figure S2. Powder X-ray diffraction patterns of the HCDMS-1


Nano Res.

Figure S3. N2 adsorption/desorption isotherms of (A) SCDMS-1, SCDMS-2 and SCDMS-3; (B) HCDMS-1, HCDMS-2 and

HCDMS-3. Corresponding desorption pore size distributions of (C) SCDMS-1, SCDMS-2 and SCDMS-3; (D) HCDMS-1,

HCDMS-2 and HCDMS-3; (E) BET surface areas versus shell thickness; (F) BET surface areas versus average pore diameter.


Nano Res.

Figure S4. Diameter distribution of HCDMSs (Statistics on 100 spheres)


Nano Res.

Figure S5. Chronoamperometric response for ORR at HCDMS-1 and Pt/C electrodes at -0.3 V in O2-saturated 0.1 M KOH

at 1600 rpm (A) Durability evaluation for 20000s. (B) on addition of 3 vol% CH3OH after about 1000s. (C) on introduction

of CO (10 vol%) after about 200s.

Figure S6. Polarization curves for oxygen reduction in O2-saturated 0.1 M HClO4 solution on HCDMS-1 and 20 wt. % Pt/C;

Scan rate: 10 mV s-1; rotation rate: 1600 rpm.


Nano Res.

Figure S7. (A) Cyclic voltammogram and (B) Linear sweep voltammogram of SCDMS-1

As shown in Figure S7, featureless voltammetric currents within the potential range between -0.8

and 0.2 V were observed for SCDMS-1, which suggested that hard template SCDMS-1 didn’t have

any ORR activity.

Table S1. The synthesis conditions and physical properties.


Nano Res.

Table S2. Structural properties of the SCDMSs.

a. BJH desorption average pore diameter

Table S3. Elemental analysis data obtained for HCDMSs.

Address correspondence to [email protected]

controlled synthesis of sustainable n-doped hollow core ... · controlled synthesis of sustainable...

Documents