A Combined DFT and Experimental Investigation of Pt-Wrapped CoNi Nanoparticles for the Oxygen Reduction Reaction

CoNi bimetallic nanoparticles wrapped with Pt were the subject of a theoretical study and experimental validation for the oxygen reduction reaction (ORR). The computational study was carried to evaluate the effect of the core composition of the Pt-wrapped CoNi nanoparticles toward the ORR. For this purpose, Pt₄₄ and Co_nNi_6−n-Pt₃₈ (0≤n≤6) octahedral nanoparticles were employed as models and the O and OH binding energies were taken into account to describe the ORR electrocatalytic activity. The experimental validation of these type of nanoparticles was performed considering two compositions (Co₃₀Ni₇₀-20Pt/C and Co₇₀Ni₃₀-20Pt/C). The Co_nNi_6−n-Pt₃₈ (0≤n≤6) nanoparticles exhibit O and OH adsorption energies weaker than the pure Pt₄₄ nanoparticles, suggesting, therefore, a higher electrocatalytic activity for the CoNi-Pt with respect to one of elemental Pt nanoparticles. The electrochemical results confirm the theoretical prediction, showing that the Co₃₀Ni₇₀-20Pt/C and Co₇₀Ni₃₀-20Pt/C electrocatalysts present higher specific activities, 400% and 300%, above that of Pt/C, respectively, as well as mass activities 50% higher than the commercial Pt/C, taken as reference. [Figure not available: see fulltext.].