Operando X-Ray Absorption Spectroscopic Study On The Effect Of Ionic Liquid Coverage Upon The Oxygen Reduction Reaction Activity Of Pd-Core Pt-Shell Catalysts

This study provides evidence of the enhancement of the oxygen reduction reaction (ORR) activity of Pt/C and Pd-core Pt-shell catalysts upon ionic liquid modification. Under high potential at 1.15 V (vs. reversible hydrogen electrode), the lower coverage of the oxide species on the Pt surface modified with [7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD)][bis(trifluoromethylsulfonyl)imide (NTf2)] ionic liquid (IL) was confirmed by electrochemical analysis. Operando X-ray absorption spectra (XAS) of the ionic liquid-modified Pd-core Pt-shell catalyst displayed smaller 5d orbital vacancies than the naked catalyst. Shrinkage of Pt-Pt bond length was also displayed, indicating the suppression of oxidation. Thus, we conclude that the IL-modified systems are effective in avoiding the adsorption of oxide species on the Pt surface and improving the oxygen reduction activity. (c) The Author(s) 2020. Published by ECSJ.