Metal-Free\nSingle Atom Catalyst for N₂ Fixation\nDriven by Visible Light

Abstract

Solar nitrogen (N₂) fixation is the most attractive\nway for the sustainable production of ammonia (NH₃), but\nthe development of a highly active, long-term stable and low-cost\ncatalyst remains a great challenge. Current research efforts for N₂ reduction mainly focus on the metal-based catalysts using\nthe electrochemical approach, while metal-free or solar-driven catalysts\nhave been rarely explored. Herein, on the basis of a concept of electron\n“acceptance-donation”, a metal-free photocatalyst, namely,\nboron (B) atom, decorated on the optically active graphitic-carbon\nnitride (B/g-C₃N₄), for the reduction of N₂ is proposed by using extensive first-principles calculations.\nOur results reveal that gas phase N₂ can be efficiently\nreduced into NH₃ on B/g-C₃N₄ through\nthe enzymatic mechanism with a record low onset potential (0.20 V).\nMoreover, the B-decorated g-C₃N₄ can significantly\nenhance the visible light absorption, rendering them ideal for solar-driven\nreduction of N₂. Importantly, the as-designed catalyst\nis further demonstrated to hold great promise for synthesis due to\nits extremely high stability. Our work is the first report of metal-free\nsingle atom photocatalyst for N₂ reduction, offering cost-effective\nopportunities for advancing sustainable NH₃ production.