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/CPNIPAM, 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/CPNIPAM 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/CPNIPAM 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.