New opportunities for efficient N-2 fixation by nanosheet photocatalysts

Catalytic ammonia synthesis from dinitrogen (N-2) under mild conditions has been considered to be the holy grail of N-2 fixation, which is one of the most important chemical processes in the agriculture, biological and industrial fields. Given that current artificial N-2 fixation is still dominated by the energy-intensive Haber-Bosch process, solar N-2 fixation represents an encouraging and fascinating route for carbon-free and energy-saving N-2 fixation. However, its practical application is seriously hampered by surface sluggish reaction kinetics. In this minireview, we share our perspectives on the use of two-dimensional (2D) nanosheets for the manipulation of photocatalytic N-2 fixation. Nanosheet photocatalysts serve as the perfect platform for the engineering of surface active sites, including defects and iron, all of which can not only bolster photon-exciton interaction toward robust charge carriers generation upon light absorption, but also mimic the function schemes of MoFe-cofactor in nitrogenase toward sufficient N-2 binding and activation. These merits endowed by nanosheets photocatalysts provide instructive information on exploring the rich nitrogen photochemistry on solid surfaces and offer new opportunities for the design of novel photocatalysts towards efficient N-2 fixation.