Recent progress in advanced catalysts for electrochemical nitrogen reduction reaction to ammonia

Due to its use of renewable energy and environmental friendliness, the electrochemical nitrogen reduction process (eNRR) has become a promising substitute for the manufacturing of ammonia. Despite extensive exploration of eNRR catalysts, an optimal catalyst has not been reported to date. Therefore, it is imperative to develop rational catalysts to enhance NH3 synthesis efficiency. In order to offer suggestions for catalyst design, recent developments in electrocatalysts for eNRR are summarized in this paper. Firstly, the eNRR mechanism is briefly introduced. Secondly, the design strategies of eNRR catalysts were summarized in terms of morphology, structure, vacancies, doping, synergistic effect, heterojunction and single atom. Subsequently, the application of in situ mass spectrometry, in situ infrared, in situ XAS and in situ Raman to the NRR reaction is discussed. The importance of the density-functional theory (DFT) method for the study of reaction energy barriers and catalyst electron-orbital distributions during eNRR catalysis is discussed. Finally, this review presents the potential challenges and future perspectives of eNRR.