Cation‐vacancy‐enriched nickel phosphide for efficient electrosynthesis of hydrogen peroxides

Zheng Zhou, Yuan Kong, Hao Tan*, Qianwei Huang, Cheng Wang, Zengxia Pei, Haozhu Wang, Yangyang Liu, Yihan Wang, Sai Li, Xiaozhou Liao, Wensheng Yan, Shenlong Zhao*
Advanced Materials, 34(16), 2106541, (2022)
DOI:https://doi.org/10.1002/adma.202106541

Abstract

Electrocatalytic hydrogen peroxide (H2O2) synthesis via the two-electron oxygen reduction reaction (2e ORR) pathway is becoming increasingly important due to the green production process. Here, cationic vacancies on nickel phosphide, as a proof-of-concept to regulate the catalyst’s physicochemical properties, are introduced for efficient H2O2 electrosynthesis. The as-fabricated Ni cationic vacancies (VNi)-enriched Ni2−xP-VNi electrocatalyst exhibits remarkable 2e ORR performance with H2O2 molar fraction of >95% and Faradaic efficiencies of >90% in all pH conditions under a wide range of applied potentials. Impressively, the as-created VNi possesses superb long-term durability for over 50 h, suppassing all the recently reported catalysts for H2O2 electrosynthesis. Operando X-ray absorption near-edge spectroscopy (XANES) and synchrotron Fourier transform infrared (SR-FTIR) combining theoretical calculations reveal that the excellent catalytic performance originates from the VNi-induced geometric and electronic structural optimization, thus promoting oxygen adsorption to the 2e ORR favored “end-on” configuration. It is believed that the demonstrated cation vacancy engineering is an effective strategy toward creating active heterogeneous catalysts with atomic precision.