Progress in Mo/W-based electrocatalysts for nitrogen reduction to ammonia under ambient conditions

Abstract

Ammonia (NH₃), possessing high hydrogen content and energy density, has been widely employed for fertilizers and value-added chemicals in green energy carriers and fuels. However, the current NH₃ synthesis largely depends on the traditional Haber–Bosch process, which needs tremendous energy consumption and generates greenhouse gas, resulting in severe energy and environmental issues. The electrochemical strategy of converting N₂ to NH₃ under mild conditions is a potentially promising route to realize an environmentally friendly concept. Among various catalysts, molybdenum/tungsten-based electrocatalysts have been widely used in electrochemical catalytic and energy conversion. This review describes the latest progress of molybdenum/tungsten-based electrocatalysts for the electrochemical nitrogen reduction reaction. The fundamental roles of morphology, doping, defects, heterojunction, and coupling regulation in improving electrocatalytic performance are mainly discussed. Besides, some tailoring strategies for enhancing the conversion efficiency of N₂ to NH₃ over Mo/W-based electrocatalysts are also summarized. Finally, the existing challenges and limitations of N₂ fixation are proposed, as well as possible future perspectives, which will provide a platform for further development of advanced Mo/W-based N₂ reduction systems.