Defect and Interface Engineering on Two-Dimensional Nanosheets for the Photocatalytic Nitrogen Reduction Reaction

Reducing dinitrogen (N-2) to ammonia (NH3) under mild conditions is a very significant nitrogen cyclic process, which plays a vital role in agricultural, biological and industrial fields. The Haber-Bosch process as a current mainstream way of N-2 fixation has particularly high energy consumption, occupying about 1 % of the world energy production. In contrast, the photocatalytic N-2 reduction reaction provides a green route almost without energy consumption and environmental pollution. However, there are many challenges that needs to be solved urgently, such as, for example, low quantum yield, inefficient N-2 adsorption and activation and an unclear N-2 fixation mechanism. Nowadays, tactics for improving the catalytic performance mainly focus on producing more active sites via defect or interface engineering. Generally, two-dimensional materials with defect or interface engineering can not only accelerate photon-exciton interactions, but also enhance sufficient N-2 binding, activation and hydrogenation. In this Minireview, we will first summarize the principles of photocatalytic N-2 fixation, and then discuss progress in the development two-dimensional (2D) materials with defect and interface engineering for photocatalytic N-2 fixation. Finally, we describe ammonia detection methods and recent important developments and challenges in this field.