New opportunities for efficient N₂ fixation by nanosheet photocatalysts

Abstract

Catalytic ammonia synthesis from dinitrogen (N2) under mild conditions has been considered to be the "holy grail" of N2 fixation, which is one of the most important chemical processes in the agriculture, biological and industrial fields. Given that current artificial N2 fixation is still dominated by the energy-intensive Haber-Bosch process, solar N2 fixation represents an encouraging and fascinating route for carbon-free and energy-saving N2 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 N2 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 N2 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 N2 fixation.

Tuning Oxygen Vacancies in Ultrathin TiO2 Nanosheets to Boost Photocatalytic Nitrogen Fixation up to 700 nm

“…Recently, defect engineering in semiconductor photocatalysts has attracted attention as a means of providing abundant active sites for optimizing reactant (e.g., N 2 and H 2 O) adsorption and lowering activation energy barriers for challenging chemical transformations . Recently, it was demonstrated that ultrathin CuCr‐layered double hydroxides (LDHs) nanosheets containing abundant oxygen vacancies (V O ) exhibited outstanding N 2 reduction activities at wavelengths up to 500 nm.…”

Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

“…In Table 2 , we summarize the performance of recently published photoelectrocatalysts for NRR. Comprehensive discussions of photocatalytic N 2 reduction can be found elsewhere, and are beyond the scope of this article.…”

“…Photochemical systems are considered to be clean and renewable due to the use of light, potentially solar, as the energy source. The detailed discussion of progress in molecular NRR catalysts and photochemical NRR can be found elsewhere . Compared with electrochemical systems, photochemical systems are not as efficient because only a portion of photons with particular wavelengths can participate in the reaction.…”

Ultrathin Two‐Dimensional Semiconductors for Photocatalysis in Energy and Environment Applications

“…Recent reports indicate that 2D semiconductors are potential candidates for photocatalytic nitrogen fixation . Recently, Wang and coworkers adopted Au nanocrystal modified ultrathin 2D TiO 2 nanosheets with abundant oxygen vacancies for nitrogen fixation.…”