Synergistically enhanced oxygen reduction reaction through the optimal adsorption of oxygen molecules in a sub-5 nm-sized Pt0.4Zn0.1Ni0.5 ternary ensemble alloy catalyst

This study aimed to develop an oxygen reduction reaction (ORR) catalyst with high O2 adsorption capacity by introducing Zn into a PtNi alloy. The three-way alloy was synthesized by incorporating Ni and Zn, which are compatible with hydrogen and oxygen, and significantly reducing the Pt component to <40 %. The ensemble particles were loaded onto a carbon black (CB) support to obtain the electrocatalyst. The substitution of Ni by Zn (CB–O–ZnNiPt) helped lower the d-band of Pt, and O2 adsorption improved with the addition of Zn. Moreover, existence of ZnO facilitated the adsorption of H+. The Pt0.4Ni0.5Zn0.1/CB ensemble electrode exhibited excellent mass activity (1.40 A mg−1), specific activity (7.15 mA cm−2), and turnover frequency (1.54 e−1 s−1) at 0.9 V, and the electrochemical performance remained unchanged even after 5000 cycles. We believe that Ni and Zn served as redox pairs in the Pt0.4Ni0.5Zn0.1/CB ensemble electrode to enable optimal O2 adsorption and partitioning, synergistically improving the ORR performance.