Study of precursor-dependent CuS nanostructures: crystallographic,morphological, optical and photocatalytic activity

AMANJOT KAUR1,*, BALWINDER KAUR2, KARAMJIT SINGH1, RAJESH KUMAR3

and SUBHASH CHAND4

1Physics Department, Punjabi University, Patiala 147002, India2Chemistry Department, Punjabi University, Patiala 147002, India3Department of Chemistry, GDC Sugh-Bhatoli, Kangra 176022, India4Department of Chemistry, L.R.D.A.V. College, Jagraon 142026, India

*Author for correspondence (aman.chahal1@gmail.com)

MS received 27 March 2021; accepted 23 July 2021

Abstract. Diethylenetriamine (DETA)-assisted solvothermal method is explored for the synthesis of CuS nanostructures

(NSs). Cu(ethylxanthate)2, Cu(morpholine-4-dithiocarbamate)2 and Cu(piperazine-1-dithiocarbamate)2 are used as effi-

cient single source precursors for the synthesis of CuS NSs. DETA acts as stabilizing as well as reducing agent.

Diffraction and electron microscopy techniques are used for the analyses of crystallographic and morphological features

of the synthesized NSs. Synthesized NSs crystalize in hexagonal crystal structure, having average crystallite size *28.95,

32.85 and 33.30 nm for CuS prepared from Cu(ethylxanthate)2, Cu(morpholine-4-dithiocarbamate)2 and Cu(piperazine-1-

dithiocarbamate)2 precursors, respectively. Transmission electron microscope analysis shows the formation of multi-

faceted NSs. Topographical studies carried out with the help of field-emission scanning electron microscope reveal the

agglomeration of layered NSs. Photocatalytic activity of synthesized CuS NSs is assessed by evaluating the degradation of

methylene-blue dye aqueous solution under visible light irradiation. Photocatalytic activity dependence on morphology is

thoroughly studied.

Keywords. Copper sulphide; nanostructures; crystallography; morphology; solvothermal synthesis.

1. Introduction

Owing to the size-tunable properties of nanomaterials,

they have attracted extensive attention by the various

research groups in recent years. Size-tunable properties

of nanomaterials are because of two chief reasons:

increase in surface to volume ratio with decrease in

particle size and quantum confinement effect. This

makes them attractive for widespread applications, for

example, in industries i.e., textiles, cosmetics, construc-

tion, military, nano-medicine, green technology, etc. A

lot of research has been done on semiconductor metal

sulphide nanomaterials like CdS [1], PbS [2], HgS [3],

SnS [4], etc., but the toxicity of these nanomaterials

limits their extensive applications. Among the plethora

of chalcogenide-based nanomaterials, copper sulphide

exhibits unique electronic, optical and chemical proper-

ties. Copper sulphide has captured attention of various

research groups in recent years because of its broad

stoichiometric composition from copper-deficient (CuS2)

region to copper- rich (Cu2S) region with various mor-

phology evolutions [5]. CuxS (x = 1.0–2.0) is a non-

toxic p-type semiconductor having a wide range of

bandgap (1.2–2.5 eV) [6], thus making it suitable in

various modern applications like imaging and in cancer

therapy [7], lithium ion batteries [8], UV-protection,

electromagnetic interference shielding [9], energy storage

[10], photo-fento reaction [11], solar cells [12], photo-

catalysts, etc.

Among all applications of nanomaterials, photocatalysis

is a simple and economical way for degrading hazardous

industrial effluents, and organic and inorganic pollutants

as they cause a major threat to the environment. How-

ever, various sophisticated methods are opted to treat

pollutants such as chemical treatment, wastewater treat-

ment, microbial degradation and photocatalytic degrada-

tion. Out of all the reported methods, the photocatalysis

is gaining much interest because of cost effectiveness. In

recent years, there has been extensive research in the

direction for the development of visible light-active

photocatalysts, as the UV light comprises only 4% of

solar energy, whereas visible light constitutes about 50%.

Till date, there are various visible light dynamic inor-

ganic semiconductor photocatalysts like WO3 [13], CdS

[14], BiVO4 [15], AgI [16], Ag3PO4 [17], CdSe [18],

CuS [19], etc.

Bull. Mater. Sci. (2021) 44:268 � Indian Academy of Scienceshttps://doi.org/10.1007/s12034-021-02558-4Sadhana(0123456789().,-volV)FT3](0123456789().,-volV)

Further, various morphologies of CuS such as nanorods

[20], nanoribbons [21], spheres [22], nanoparticles [23],

nanoplates [24], quantum dots [25], nanoflower-like struc-

tures [26] have been reported. These are prepared via

numerous synthesis routes like co-precipitation method

[27], sol–gel method, solvothermal technique [9], sono-

chemical method [28], dealloying [11], chemical vapour

deposition [29], polyol method [30], template-assisted

growth, microemulsion [31], wet chemical method [32],

microwave-assisted method [33], hydrothermal method

[34], etc. Out of all these techniques, hydrothermal method

is gaining interest because of high efficiency and could be

scaled up [35]. Studies have also shown that morphology of

the NSs can be tailored by various factors, such as precur-

sors concentration [36], reaction time [37], temperature

[38], capping agent [39], etc.

In the present investigation, a hydrothermal method has

been opted for the synthesis of various morphologies of CuS

NSs using Cu(ET)2, Cu(M4DTC)2 and Cu(Pi1DTC)2(where ET, M4DTC and Pi1DTC are ethylxanthate, mor-

pholine-4-dithiocarbamate and piperazine-1-dithiocarba-

mate, respectively) as single source precursors. The

synthesized nanoparticles were characterized by X-ray

diffraction (XRD), transmission electron microscope

(TEM), field emission scanning electron microscope (FE-

SEM), energy X-ray dispersive spectroscope (EDS) and

UV–visible (UV–vis) spectroscope. Furthermore, photo-

catalytic potential properties of synthesized NSs were

checked by degrading organic pollutant under visible light

irradiation.

2. Experimental

2.1 Materials

All the analytical reagent grade chemicals; potassium

hydroxide (KOH), diethyl ether (C2H6O), morpholine

(C4H8ON), carbon disulphide (CS2), sodium hydroxide

(NaOH), piperazine (C4H8N2), diethylenetriamine (DETA;

N3C4H12), ethanol (C2H5OH) and methylene blue dye

(C16H18N3SCl) were procured from S.D. Fine Chemical

Limited. All the reagents were used without further

purification.

2.2 Preparation of potassium ethylxanthate, morpholine-4-dithiocarbamate and piperazine-1-dithiocarbamate

Potassium ethylxanthate, piperazine-1-dithiocarbamate and

morpholine-4-dithiocarbamate were synthesized by the

procedure as already described by Kaur et al [40]. Sche-matic synthesis route of potassium ethylxanthate is repre-

sented in figure 1, while that of M4DTC and Pi1DTC are

represented in figure 2.

2.3 Preparation of copper complexes

Cu(ET)2 was prepared by dissolving 25 ml aqueous solution

of 5 mmol copper acetate to 25 ml aqueous solution of 0.01

mol potassium ethylxanthate. The mixture was stirred at

800 rpm at room temperature for 30 min, solid precipitates

formed were washed five times with 10 ml distilled water

each time followed by filtration through 110 mmWhatmann

filter paper. Similar procedure was applied for the prepa-

ration of Cu(M4DTC)2 and Cu(Pi1DTC)2. The schematic

route for the synthesis of Cu(ET)2 is represented in figure 1,

while for Cu(M4DTC)2 and Cu(Pi1DTC)2 are represented

in figure 2.

Figure 1. Schematic synthesis route of potassium ethylxanthate

and Cu(ET)2.

Figure 2. Schematic synthesis route of M4DTC, Pi1DTC,

Cu(M4DTC)2 and Cu(Pi1DTC)2.

268 Page 2 of 10 Bull. Mater. Sci. (2021) 44:268

2.4 Preparation of CuS NSs

Copper sulphide NSs were prepared from single source

copper precursors: [Cu(ET)2], [Cu(M4DTC)2] and

[Cu(Pi1DTC)2] via hydrothermal method. CuS NSs were

prepared by transferring 0.5 g of copper precursors and 15

ml of DETA in Teflon-lined autoclave maintained at 170�Cfor 5 h. DETA acts as stabilizing and reducing agent. The

black product was separated by centrifugation, washed five

times by 10 ml deionized water and 10 ml ethanol each

time, then dried in hot air oven for 3 h. The schematic

synthesis route of CuS NSs by using Cu(ET)2 as precursor

is represented in figure 3, and using Cu(M4DTC)2 and

Cu(Pi1DTC)2 as precursors are represented in figure 4.

2.5 Instrument

For the detailed crystallographic characterization of

synthesized NSs and powder XRD patterns were recorded

using Rigaku Miniflex-600 Powder X-ray diffractometer, in

2h range of 20�–80� at scan speed of 4 min–1 keeping

step size 0.02�. For morphological analyses, electron

micrographs were recorded on Hitachi (H-7650) electron

microscope at accelerating voltage of 80 kV. For TEM

studies, the samples were prepared by dispersing 1 mg syn-

thesized NSs in 5 ml ethanol followed by 15 min of ultra-

sonication at room temperature. A drop of well-dispersed

ethanolic solution was placed on carbon-coated copper grid.

Then the dried sample was placed on the electron microscope

for further studies. The UV–vis absorption spectra

(k = 300–700 nm) of synthesized CuS NSs were recorded

using Hitachi (2J1-0004) UV–visible absorption spec-

trophotometer by dissolving 2 mg of nanopowder in 20 ml

ethanol at room temperature. The topographical and chemical

composition analyses were done using FE-SEM with EDS

attachment (NOVA NANOSEM-450).

2.6 Measurement of photocatalytic activity

The photocatalytic activity of the synthesized nano-photo-

catalysts was investigated using methylene blue (MB) dye

as a test contaminant in aqueous media under visible light

irradiation. First, dye stock solution was prepared in aque-

ous media by dissolving 6 mg dye in 1000 ml of water.

Then 14 mg of CuS NSs was suspended in 100 ml of

aqueous dye solution followed by vigorous stirring in dark

for 60 min for equilibration of solution to ensure maximum

adsorption of dye on the surface of nano-photocatalyst.

Then the solution illuminated in visible light for total 90

min along with collection of 5 ml sample after every 10 min

of irradiation, the collected aliquots were analysed using

UV–vis absorption spectrophotometer to check the photo-

degradation of MB dye. The characteristic absorption peak

of MB dye at 663 nm was used to assess the extent of

degradation. The degradation efficiency of photocatalyst is

defined by equation 1

g% ¼ Ao � At

Ao

� 100; ð1Þ

where g = degradation efficiency, Ao and At are the absor-

bance of MB at 663 nm in dark and under light irradiation

(at t min), respectively.Figure 3. Schematic synthesis route of CuS NSs prepared from

Cu(ET)2.

Figure 4. Schematic synthesis route of CuS NSs prepared from

Cu(M4DTC)2 and Cu(Pi1DTC)2.

Bull. Mater. Sci. (2021) 44:268 Page 3 of 10 268

3. Results and discussions

The growth of CuS NSs by using different ligands was done

to know the effect of the same on the morphology of the

products. In this regard, ET, M4DTC and Pi1DTC were

used as ligands. A detailed morphological difference and its

importance to photocatalysis are discussed below.

3.1 Crystallographic analyses

Figure 5 shows the powder XRD patterns of the synthesized

CuS NSs prepared from different copper complexes at

170�C for 5 h. The diffraction peaks were indexed with

standard hexagonal CuS phase with JCPDS card no. 06-

0464 and the cell parameters a = 3.792 and c = 16.344 [41].

From XRD patterns, it can be clearly seen that the products

are in pure phase. The XRD patterns show the peaks situ-

ated at 2h-values 26.58�, 28.03�, 29.35�, 32.5�, 34.66�,41.91�, 46.5�, 51.68�, 55.19�, 57.72�, 67.85� and 72.08�corresponding to (100), (101), (102), (103), (006), (106),

(110), (108), (202), (203), (207) and (212) planes for CuS

prepared from [Cu(ET)2]. Whereas for CuS prepared from

[Cu(M4DTC)2] and [Cu(Pi1DTC)2], there is no shift in

peak positions. Peak broadening observed in recorded

diffractograms revealed the formation of CuS nanocrystal-

lites. Using Debye Scherrer formula equation (2),

D ¼ 0:89kbcosh

; ð2Þ

where D is average crystalline size, b the full-width at half-

maxima of the peak at diffraction angle h and k the

wavelength of X-rays. Average crystallite size values of

synthesized CuS NSs from precursors [Cu(ET)2],

[Cu(M4DTC)2] and [Cu(Pi1DTC)2] calculated are 28.95,

32.85 and 33.30 nm, respectively.

3.2 Morphological analyses

3.2a TEM analyses: The recorded TEM micrographs,

figure 6, suggest that NSs have agglomerated and

multiphase structures but definitely have different

morphologies, which suggest strong dependence on the

type of ligand. The size range for the CuS synthesized from

precursors [Cu(ET)2], [Cu(M4DTC)2] and [Cu(Pi1DTC)2]

is 25–50, 40–90 and 68–114 nm, respectively.

3.2b FE-SEM analyses: For further clarification on the

morphology of the synthesized NSs, FE-SEM images

(figure 7) were taken. CuS NSs prepared from different

ligands show various shapes along with layered structures

having smallest NSs of CuS prepared from Cu(ET)2precursor.

3.3 Optical analyses

In order to determine the optical properties of synthe-

sized NSs, their UV–vis absorption spectra from 300

to 700 nm are recorded (figure 8). To evaluate the

energy bandgap values, Tauc’s relation was applied as

in equation (3),

ahmð Þn¼ A hm� Eg

� �; ð3Þ

where a is absorption coefficient, n is either 2 for direct

transition or 12for indirect transition, hm is photon energy,

A is a constant and Eg the energy bandgap. Thus, energy

bandgap was calculated by extrapolating straight line at

the linear part of the curve. Inset of figure 8 shows the

graphs between (ahm)2 and hm for the CuS prepared from

precursors [Cu(ET)2], [Cu(M4DTC)2] and [Cu(Pi1DTC)2].

The obtained bandgap values came out to be 2.57, 3.05

and 2.89 eV, respectively. The above results implicate

that the electronic structure of CuS NSs can be easily

tuned with type of ligand and the synthesized NSs

have suitable bandgap values for the photocatalytic

degradation of organic pollutants under visible/solar light

irradiation.

3.4 Elemental composition

To determine the elemental composition of synthesized

NPs, EDS spectra were recorded. Figure 9a–c reveals

the formation of CuS by the presence of Cu and S

elements.Figure 5. XRD patterns of CuS NSs prepared from (a) Cu(ET)2,(b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2.

268 Page 4 of 10 Bull. Mater. Sci. (2021) 44:268

Along with Cu and S, the presence of other constituent

elements carbon and oxygen were also recorded and their

corresponding weight% and atomic% values are given in

table, inset in figure 9a–c for CuS prepared from precursors

[Cu(ET)2], [Cu(M4DTC)2] and [Cu(Pi1DTC)2], respec-

tively. Source of carbon is the double-sided adhesive carbon

tape, which was used to mount the NPs on the aluminium

stubs for EDS studies and the oxygen may be from the

adsorbent air.

3.5 Photocatalytic activity

The photocatalytic activity of the synthesized CuS NSs was

evaluated by the efficient degradation of MB dye solution

under visible light irradiation and the measurement was

taken using UV–vis absorption spectrophotometer. The

photocatalytic reaction mechanism can be described as

follows:

CuSþ hm ! CuS hþVB þ e�CB� �

The oxidation of water by holes (H2O , Hþ þ OH�Þ

hþVB þ H2O ! �OHþ Hþ

The transient formation of hydroperoxide radicals:

e�CB þ O2 gð Þ ! �O�2

O�2 þ Hþ ! HO2

2HO2 ! H2O2

H2O2 þ e� ! 2OH�

MBþ �OH ! CO2 þ H2Oþ SO2�4 þ NH4

The whole reaction scheme is represented in figure 10.

Before the photocatalytic reaction, the sample suspension

was stirred at 100 rpm at room temperature for 60 min in

dark to attain the absorption–desorption equilibrium.

Figure 11 shows the UV–vis absorption spectra of MB dye

for different durations of visible light irradiation exposure

in the presence of CuS NSs prepared from precursors

Cu(ET)2, Cu(M4DTC)2 and Cu(Pi1DTC)2. Figure 12 indi-

cates that the amount of dye adsorbed on the CuS NSs

prepared from precursor Cu(ET)2 is higher than CuS NSs

prepared from precursors Cu(M4DTC)2 and Cu(Pi1DTC)2,

which could be due to higher specific surface area of the

Figure 6. TEM micrographs of CuS NSs prepared from (a) Cu(ET)2, (b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2.

Figure 7. FE-SEM images of CuS NSs prepared from (a) Cu(ET)2, (b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2.

Bull. Mater. Sci. (2021) 44:268 Page 5 of 10 268

Figure 8. UV–vis absorption spectra of CuS NSs prepared from (a) Cu(ET)2, (b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2; inset: Tauc’srelation curves.

268 Page 6 of 10 Bull. Mater. Sci. (2021) 44:268

Figure 9. EDS images of CuS NSs prepared from (a) Cu(ET)2, (b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2;inset: composition table.

Bull. Mater. Sci. (2021) 44:268 Page 7 of 10 268

nano-photocatalyst. It can be clearly seen from figure 13

that CuS NSs prepared from precursor Cu(ET)2 show

maximum photocatalytic activity. After 90 min of visible

light irradiation, the degradation of dye is 39.8%, whereas

for same duration of time dye degradation values observed

in case of CuS NSs prepared from precursors Cu(M4DTC)2and Cu(Pi1DTC)2 are 25.39 and 22.2%, respectively. The

higher photocatalytic activity of CuS NSs prepared from

precursor Cu(ET)2 could be attributed to small size, which

leads to high surface to volume ratio, hence lesser proba-

bility for volume recombination due to which chances of

surface charge transfer increases. UV–vis absorption spectra

of CuS NSs prepared from precursor Cu(ET)2 show broad

absorption profile, which is well matched with source

emission profile and has a high absorption yield. Hence,

implying more number of photo-excited carriers are gen-

erated, leading to higher photocatalytic activity. In the case

of CuS NSs prepared from precursor Cu(M4DTC)2, the

absorption yield is lower than CuS NSs precursor

Cu(Pi1DTC)2. This has abruptly increased towards the

lower wavelength and the absorption profile is not broad,

leading to the generation of lower number of photo-excited

carriers, which is the reason for lower photocatalytic

activity of CuS NSs prepared from precursor Cu(Pi1DTC)2as compared to others.

Figure 10. Schematic illustration of degradation of MB dye.

Figure 11. Graphical plot of MB dye absorption spectra in the

presence of CuS NSs prepared from (a) Cu(ET)2, (b) Cu(M4DTC)2and (c) Cu(Pi1DTC)2.

268 Page 8 of 10 Bull. Mater. Sci. (2021) 44:268

Rate of photocatalytic degradation is explained by

Langmuir–Heinshelwood equation equation (4).

LnAt

Ao

¼ kt; ð4Þ

where Ao and At are the initial and at time t dye concen-

tration, respectively, and k is the pseudo-first-order rate

constant. The plot between ln(At/Ao) and time (figure 14) for

photocatalysts has been analysed.

The correlation coefficient (R2) values (table 1) are above

0.88, which suggests that the first-order kinetic model is

followed well. For synthesized photocatalysts, MB dye

degradation rate constant (k) follows the trend; CuS NSs

prepared from precursors [Cu(M4DTC)2] (k = 0.023 min–1)

[ [Cu(ET)2] (k = 0.0016 min–1) [ [Cu(Pi1DTC)2] (k =

0.0008 min–1).

Therefore, the synthesized CuS NSs can be potential

nano-photocatalysts for the degradation of aqueous pollu-

tants and organic dyes to treat the industrial wastewater.

Figure 12. MB dye adsorption spectra in the presence of CuS

nano-photocatalysts prepared from (a) Cu(ET)2, (b) Cu(M4DTC)2and (c) Cu(Pi1DTC)2.

Figure 13. Photo-degradation of MB dye vs. time in the presence

of CuS nano-photocatalysts prepared from (a) Cu(ET)2,

(b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2.

Figure 14. Kinetic study of CuS nano-photocatalysts prepared

from (a) Cu(ET)2, (b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2.

Table 1. The first-order kinetic equation for MB dye degradation

under visible light irradiation in the presence of CuS NSs prepared

from (a) Cu(ET)2, (b) Cu(M4DTC)2 and (c) Cu(Pi1DTC)2.

Photocatalysts Equations

a y = – 0.0016x – 0.3529, R2 = 0.94849

b y = – 0.0023x – 0.0551, R2 = 0.93664

c y = – 0.0008x – 0.1634, R2 = 0.8831

Bull. Mater. Sci. (2021) 44:268 Page 9 of 10 268

4. Conclusions

Highly crystalline and pristine CuS NSs are successfully

prepared from single source precursors Cu(ET)2,

Cu(M4DTC)2 and Cu(Pi1DTC)2 by efficient solvothermal

route. The calculated average crystallite size values are

*28.95, 32.85 and 33.30 nm for CuS NSs prepared from

precursors Cu(ET)2, Cu(M4DTC)2 and Cu(Pi1DTC)2,

respectively. The crystallite size values are calculated using

XRD diffractograms, which show no extra peaks indicating

the formation of pristine hexagonal CuS NSs. Electron

microscopic and spectroscopic studies infer that morphol-

ogy and electronic structure of the synthesized CuS NSs are

strongly precursor dependent. The CuS NSs prepared from

precursor Cu(ET)2 show better photocatalytic activity due

to smaller size, broad absorption profile and high

absorption yield, indicating generation of higher number

of photo-excited charge carriers. Synthesized CuS NSs

seem to have a scope in the wastewater treatment by

degradation of aqueous pollutants in the presence of solar

light irradiation.

Acknowledgements

We are thankful to Punjab Agriculture University, Ludhi-

ana, for TEM. We are also grateful to the Centre of

Nanoscience and Nanotechnology, Jamia Milia Islamia,

New Delhi, for FE-SEM and EDX.

References

[1] Kaur B, Singh K and Malik A K 2017 Dyes Pigm. 137 352

[2] Pullabhotla V R and Ngcobo M 2017 Mater. Lett. 198 156

[3] Sangsefidi F S, Zare M E and Niasari M S 2015 J. Ind. Eng.Chem. 28 197

[4] Sood R, Singh G, Bhatti H S, Singh K and Kumar D 2016

J. Nanomater. Mol. Nanotechnol. 5 1

[5] Subramanyam K, Sreelekha N, Reddy D A, Murali G, Varma

K R and Vijyalakshmi R 2017 Solid State Sci. 65 68

[6] Srellekha N, Subramanyam K, Reddy D A, Murali G, Ramu

S, Varma K R and Vijayalakshmi R 2016 Appl. Surf. Sci 378330

[7] Wang L 2016 RSC Adv. 6 82596

[8] Han Y, Wang Y, Gao W, Wang Y, Jiao L, Yuan H and Liu S

2011 Powder Technol. 212 64

[9] Hu X S, Shen Y, Xu L H, Wang L M, Lu L S and Zhang Y T

2016 Appl. Surf. Sci. 385 162

[10] Lai C H, Lu M Y and Chen L J 2012 J. Mater. Sci. Chem. 2219

[11] Xu W, Zhu S, Liang Y, Li Z, Cui Z, Yang X and Inoue A

2015 Sci. Rep. 5 18125

[12] Zhu Y, Cui H, Jia S, Zheng J, Yang P, Wang Z and Zhu Z

2016 Electrochim. Acta 208 288

[13] Cruz A M, Martnez D S and Cullar E L 2010 Solid State Sci.12 88

[14] Yan X, Wu Z, Huang C, Lio L and Shi W 2017 Ceram. Int.43 5388

[15] Li H B, Zhanf J, Huang G Y, Fu S H, Ma C, Wang B Y,

Huang Q R and Liao H W 2017 J. Nonoferr. Metal Soc. 27868

[16] Huang H, Huang N, Wang Z, Xia G, Chen M, He L, Tong Z

and Ren C 2017 J. Colloid Interface Sci. 502 77

[17] Ma P, Yu Y, Xie J and Fu Z 2017 Adv. Powder Tech. 282797

[18] Mansour A S, Gadallah A S, Sherbini A S Al, Youseef T and

Mohamed M 2017 J. Mol. Struct. 1149 626

[19] Saranya M, Santhosh C, Ramachandran R, Kollu P, Sara-

vanan P, Vinoba M, Jeong S K et al 2014 Powder Technol.252 25

[20] Zhao S, Han G and Li M 2010 Mater. Chem. Phys. 120 431

[21] Tang C, Lu R, Xue P, Bao C and Zhao Y 2008 Mater. Chem.Phys. 112 500

[22] Xu S, Wang Q, Cheng J, Meng Q and Jiao Y 2010 PowderTechnol. 199 139

[23] Dutta A and Dolui S 2008 Mater. Chem. Phys. 112 448

[24] Chu L, Zhou B, Mu H, Sun Y and Xu P 2008 J. Cryst.Growth 310 5437

[25] Nelwamondo S, Moloto M, Krause R and Moloto N 2012

Mater. Lett. 75 161

[26] Ding T Y, Wang M S, Guo S P and Huang J S 2008 Mater.Lett. 62 4529

[27] Lewis A E 2010 Hydrometallurgy 104 222

[28] Phuruangrat A, Thongtem T and Thongtem S 2013 PowderTechnol. 233 155

[29] Reijnen L, Meester B, Lange F, Schoonman J and Goossenes

A 2005 Chem. Mater. 17 2724

[30] Ding T Y, Wang M S, Guo S P, Guo G C and Huang J S

2008 Mater. Lett. 62 4529

[31] Chen L, Shang Y, Liu H and Hu Y 2010Mater. Des. 31 1661[32] Roy P, Mondal K and Srivastave S K 2008 Cryst. Growth

Des. 8 1530

[33] Liao X H, Chen N Y, Xu S, Yang S B and Zhu J 2003

J. Cryst. Growth 252 593

[34] Grace A N and Saranya M 2012 J. Nano Res. 18 43

[35] Saranya M, Ramachandran R, Samuel E J J, Jeong S K and

Grace A N 2015 Powder Technol. 279 209

[36] Mondal G, Santra A, Bera P, Acharjya M, Jana S,

Chattopadhyay D et al 2016 J. Nanopart. Res. 18 311

[37] Saranya M, Santhosh C, Augustine S P and Grace A N 2014

J. Exp. Nanosci. 9 329

[38] Barraza F F C, Faras M H, Lpez J H C, Romero M A E, Tello

M P, Urbina R H and Amarillas A P 2011 J. Comput. Theor.Nanosci. 4 596

[39] Nath S and Kalita P 2017 Mater. Today: Proc. 4 3972

[40] Kaur B, Singh K and Malik A K 2017 Dyes Pigm. 142 153

[41] Zhao W, Wang Z, Zhou L, Liu N and Wang H 2016 Mater.Sci. 10 290

268 Page 10 of 10 Bull. Mater. Sci. (2021) 44:268