· web viewsupplementary information organic-inorganic hybrid ptco nanoparticle with high...

Supplementary Information

Organic-inorganic hybrid PtCo nanoparticle with

high electrocatalytic activity and durability for

oxygen reduction

Namgee Jung, Satadeep Bhattacharjee, Sanjeev Gautam, Hee-Young Park, Jaeyune Ryu,

Young-Hoon Chung, Sang-Young Lee, Injoon Jang, Jong Hyun Jang, Sae Hum Park, Dong

Young Chung, Yung-Eun Sung, Keun-Hwa Chae, Umesh V. Waghmare, Seung-Cheol Lee

and Sung Jong Yoo

Corresponding Authors

*E-mail (S. J. Yoo): ysj@kist.re.kr

*E-mail (S.-C. Lee): leesc@kist.re.kr

Supplementary Figure S1 The optimized tetragonal L10 structure of 50-50 CoPt alloy.

Supplementary Figure S2 Slab constructed with 4 monolayers of (111) surface of L10 CoPt

alloy. (a) top view (b) side view.

Supplementary Figure S3 TGA curves of bare carbon and C-PNIPAM.

Supplementary Figure S4 UV-Vis absorption spectra of (a) Pt precursors with and without

PNIPAM, and (b) Co precursors with and without PNIPAM in solvents. A red arrow in

Figure S1b indicates the decrease in absorption intensity (hypochromism) of Co-PNIPAM

due to the strong interaction between Co precursor and PNIPAM.

Supplementary Figure S5 N 1s core-level XPS spectra of C-PNIPAM, bare carbon, and

PtCo/C without PNIPAM.

Supplementary Figure S6 N 1s core-level XPS spectra of Co/C-PNIPAM, Co/C, Pt/C-

PNIPAM, and Pt/C. N 1s XPS data for Co/C-PNIPAM and Pt/C-PNIPAM were

deconvoluted, respectively. Blue, red, and green lines indicate the amide N peak, Co-N peak,

and background, respectively.

Supplementary Figure S7 XRD patterns of PtCo/C and PtCo/C-PNIPAM.

Supplementary Figure S8 (a) Pt LIII-edge XANES spectra of Pt/C and Pt/C-PNIPAM and

(b) Co L-edge NEXAFS spectra of Co/C and Co/C-PNIPAM.

Supplementary Figure S9 Deconvoluted Pt 4f core-level XPS spectra of PtCo/C and

PtCo/C-PNIPAM.

Supplementary Figure S10 The ORR polarization curves of pristine carbon and C-PNIPAM

in O2-saturated 0.1 M HClO4 solution. The inset indicated the enlarged graph.

Supplementary Figure S11 The ORR polarization curves of Pt/C, PtCo/C, and PtCo/C-

PNIPAM in O2-saturated 0.1 M HClO4. The potentials were scanned by 5 mV s-1 with the

RDE rotating speed of 1600 rpm.

Supplementary Figure S12 The ORR polarization curves of (a) Co/C and Co/C-PNIPAM in

O2-saturated 0.1 M KOH, and (b) Pt/C and Pt/C-PNIPAM in O2-saturated 0.1 M HClO4. The

potentials were scanned by 5 mV s-1 with the RDE rotating speed of 1600 rpm.

Supplementary Table S1 Deconvoluted XPS data according to the binding energy estimated from N 1s core-level XPS spectra of samples with PNIPAM.

Supplementary Table S2 Deconvoluted XPS data according to the binding energy estimated from Co 2p core-level XPS spectra of PtCo/C and PtCo/C-PNIPAM.

Supplementary Table S3 Deconvoluted XPS data according to the binding energy estimated from Pt 4f core-level XPS spectra of PtCo/C and PtCo/C-PNIPAM.

Supplementary Table S4 Electrochemical surface areas (ESAs) of PtCo/C and PtCo/C-PNIPAM before and after the ADT.

a The ESAs were calculated from the charge density associated with monolayer hydrogen adsorption of 210 µC cm-2 in the Hupd region in CV.b It was assumed that the ESA before the ADT was 100 % for each sample.