Dianion Induced Electron Delocalization of Trifunctional Electrocatalysts for Rechargeable Zn-Air Batteries and Self-Powered Water Splitting

The development of low-cost multifunctional electrocatalysts with high activity for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) is critical for the advancement of sophisticated energy conversion and storage devices. Herein, a trifunctional Ni(S0.51Se0.49)(2)@NC catalyst is designed and fabricated using a dianionic regulation strategy. Synchrotron radiation X-ray absorption spectroscopy and density functional theory calculations reveal that simultaneous sulfidation and selenization can induce the electronic delocalization of Ni(S0.51Se0.49)(2) active sites to enhance the adsorption of *OOH/*OH intermediate for ORR/OER and H* intermediate for HER. The OER and HER mechanisms are revealed by in situ Raman spectroscopy. The Ni(S0.51Se0.49)(2)@NC exhibits trifunctional catalytic activity for the HER (111 mV at 10 mA cm(-2)), OER (320 mV at 10 mA cm(-2)), and ORR (half-wave potential of 0.83 V). The rechargeable zinc-air batteries (ZABs) exhibit an open-circuit voltage of 1.46 V, a specific capacity of 799.1 mAh g(-1), and excellent stability for 1000 cycles. The water electrolytic cell using Ni(S0.51Se0.49)(2)@NC electrodes delivers a current density of 10 mA cm(-2) at a cell voltage of 1.59 V, and it can be powered using the constructed ZABs. These findings contribute to developing low-cost and efficient non-noble metal multifunctional catalysts.