Construction of robust Cu-N4-Pt bond connecting Cu single atoms support and Pt for augmented electrocatalytic process

Abstract

Transition metal single atoms are widely applied in hydrogen fuel cells, either as primary active sites or as support to load catalysts. However, the bonding interactions existing between them and catalysts have been poorly studied. In this work, we first involved a theoretical analysis to validate the augmentation of electrocatalytic activity in platinum (Pt) by introducing copper (Cu) single atoms as support. As Pt size decreases, a distinctive Cu-N4-Pt bond emerges between the Cu single atoms and Pt. This bond serves to diminish the formation energy leading to enhance stability, and redistribute charge within the Pt structure contributing to a significant improvement in its electrocatalytic activity. Based on the principles of theoretical analysis, and in pursuit of prospective hydrogen fuel cell catalysts, we prepared Fenton-inert, low-density Cu single atoms to support around 2-nm Pt, named Pt@Cu/NC. Our findings show that the Cu single atoms effectively interact with Pt, leading to exceptional catalytic activities for both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), even with a merely 4.7 wt% Pt content. Particularly within the fuel cell applications, Pt@Cu/NC catalyst exhibits a notable peak power density of 860 mW cm−2 and an impressively stability that exceed commercial Pt/C.