Abstract:

Noble metal nanoclusters have received widespread attention due to their special structure and distinct chemical composition. Bimetallic metal nanoclusters with precise particle size and structure were used in this study to investigate the effect of electronic and geometric structure on the catalytic reaction. The electron coupling between heteroatom and the host atom could regulate the catalytic performance. To create the well-dispersed electrochemical catalysts, carbon nanosheets supported Au₄Pd₂ nanoclusters (NCs) with a high surface area. The X-ray photoelectron spectroscopy (XPS) test revealed that the synergistic effect of AuPd and the support could promote ORR and HER stability. The ORR performance of Au₄Pd₂-CNs-2 with the initial potential of 0.95 V and the half-wave potential of 0.81 V was better than those of commercial Pd/C in the 0.1 mol/L KOH. The catalyst also demonstrated excellent catalytic activity towards HER with the overpotential of 129 mV at 10 mA/cm² in 0.5 mol/L H₂SO₄. The structure and morphology of catalysts are determined using X-ray diffraction (XRD) and transmission electron microscopy (TEM), and electrochemical measurements are used to test the electrocatalytic performances. Ultra-small single-cluster catalysts could improve the utilization and electrocatalytic activity of atoms, and the synergy effects between Au and Pd also enhance the catalytic activity of catalysts. By optimizing the doping ratio of Au₄Pd₂ NC_s, bifunctional catalysts with excellent oxygen reduction and hydrogen evolution performance were obtained, providing a new direction for developing non-platinum-based catalysts with high efficiency and stability.

Key words: noble metal nanoclusters, electrocatalysts, zinc-air batteries, oxygen reduction reaction, hydrogen evolution reaction