Recent Advances in Nonprecious Metal Oxide Electrocatalysts and Photocatalysts for N₂ Reduction Reaction under Ambient Condition

NH₃ plays an indispensable role in agriculture, fertilizer production as well as in the chemical industry. However, its large-scale production still relies deeply on the century-old Haber-Bosch process under high temperature and pressure along with greenhouse gas emission and fossil fuel consumption. The electrocatalytic and photocatalytic N₂ reduction reactions (NRRs) for NH₃ production are favorable approaches to avoid these issues because they are carbon-neutral and energy-saving. Recently, the nonprecious metal oxides (NPMO) have gathered the most attention due to their ease of synthesis, controllable stability, lower cost, and environmental friendliness. Herein, the recent advances in NPMO electrocatalysts and photocatalysts for the NRR are narrated and the strategies to improve the poor NRR activity of pristine NPMOs by heteroatom doping to engineer their surface-active sites and introduction of oxygen vacancies are highlighted. A brief summary of and the future perspective on this research field are also presented.