Lattice Oxygen-Induced <i>d</i>-Band Shifting for Enhanced Hydrogen Oxidation Reaction on Nickel
Chang Sun, Pengcheng Zhao, Yongqing Yang, Zhuo Li, Wenchao Sheng
Abstract
The application of anion exchange membrane fuel cells is hampered by the development of highly efficient and earth-abundant anode hydrogen oxidation reaction (HOR) catalysts. Here, a series of nickel catalysts (denoted as Ni-X) with different lattice oxygen (LO) contents were synthesized by H2 reduction of nickel hydroxide at temperatures (X) ranging from 300 to 500 °C. The Ni-400 (LO/Ni = 0.41, NiO0.41) catalyst with an optimum LO content showed excellent HOR activity and stability, comparable to current Ni-based electrocatalysts. An X-ray photoemission spectroscopic study, combined with density functional theory calculations, suggested that introducing LO into Ni modified the metal d-band electronic structure and in turn the hydrogen binding energy, which played a major role in determining the HOR performance.