Two-dimensional materials for NOx reduction to ammonia: From electrocatalyst to system

Abstract

Ammonia is a globally produced commodity chemical that is essential in supporting the needs of an expanding population. The traditional Haber-Bosch process for the production of ammonia, although effective, encounters obstacles stemming from its reliance on fossil fuels and substantial energy expenditure. The electrocatalytic NO_x reduction reaction (NO_xRR) for ammonia synthesis has recently captured interest as a compelling alternative due to its high efficiency and environmentally friendly characteristics. Two-dimensional (2D) materials, with their numerous exposed active sites, substantial specific surface area, excellent conductivity, and readily adjustable electronic properties, offer significant potential for activating NO_x species in sustainable NO_xRR applications. This review highlights the latest research advancements in the use of 2D materials for electrochemical NO_x reduction. We began by providing an overview of the fundamental principles of electrochemical NO_x reduction. Next, we introduced recent progress in this field using 2D materials such as graphene, MXene, metal alloys/sulfides, layered double hydroxides, and carbon nitride. We then summarized the state-of-the-art electrochemical systems employed in NO_xRR processes. Finally, we discussed the challenges and prospects of NO_xRR based on 2D materials, aiming for large-scale industrial implementation in the near future.