Outstanding Oxygen Reduction Reaction Catalytic Performance of In–PtNi Octahedral Nanoparticles Designed via Computational Dopant Screening

Abstract

PtNi octahedral nanoparticles are considered as one of the best-performing catalysts for the oxygen reduction reaction (ORR). However, Ni dissolution deteriorates their catalytic activity and stability during the ORR. Here, we report a strategy that improves the ORR activity and stability of the PtNi octahedral nanoparticle catalyst through the incorporation of a novel dopant. Computational screening with seven different elements (Bi, In, Ru, Sn, Te, Zn, and Zr) suggests In as the most promising candidate based on the metal doping energy and the OH* adsorption energy. Consideration of the OH* coverage and Ni diffusion energy demonstrates the superior ORR activity and stability of the In-doped PtNi(111) structure. The calculation results were validated by synthesizing In-doped PtNi octahedral nanoparticles on a carbon support (In–PtNi/C). In–PtNi/C demonstrated excellent ORR performance outcomes (1.36 A mgPt–1 and 2.64 mA cm–2@0.9 VRHE), which were 2.1 and 7.9 times higher in terms of the mass activity and 2.4 and 13.4 times higher in terms of the specific activity compared to PtNi/C and Pt/C, respectively. After 12k potential cycles, In–PtNi/C showed excellent stability with high Ni retention; 2.4 and 43% of Ni were lost from In–PtNi/C and PtNi/C, respectively. Computational and experimental investigation demonstrates that surface-doped In creates a new active site toward the ORR and blocks Ni diffusion to the surface by making Pt less oxophilic.