Two dimensional electrocatalyst engineering via heteroatom doping for electrocatalytic nitrogen reduction.

The electrocatalytic N reduction reaction (eNRR) - which can occur under ambient conditions with renewable energy input - became a promising synthetic pathway for ammonia (NH) and has attracted growing attention in the past few years. Some achievements have been made in the eNRR; however, there remain significant challenges to realize satisfactory NH production. Therefore, the rational design of highly efficient and durable eNRR catalysts with N[triple bond, length as m-dash]N bond activating and breaking ability is highly desirable. Two-dimensional (2D) materials have shown great potential in electrocatalysis for energy conversion and storage. Although most 2D materials are inactive toward the eNRR, they can be activated by various modification methods. Heteroatom doping engineering can impact the charge distribution and spin states on catalytic sites, therefore accelerating the dinitrogen adsorption and protonation process. This review summarises the recent research progress of heteroatom-doped 2D materials, including carbon, molybdenum disulfide (MoS) and metal carbides (MXenes), for the eNRR. In addition, some existing opportunities and future research directions in electrocatalytic nitrogen fixation for ammonia production are discussed.