The use of single-metal atom-based photocatalysts for the production of ammonia through photocatalytic nitrogen fixation

The conventional synthetic ammonia industry is characterized by its high energy consumption, necessitating the exploration of a new environmentally sustainable method for NH₃ synthesis. The photocatalytic nitrogen reduction reaction (pNRR) allows NH₃ production under room conditions. The optimization of photocatalysts, particularly through the use of single-metal atom catalysts (SMACs), plays a significant role in enhancing the performance of pNRR. SMACs have garnered growing attention in photocatalysis for their exceptional catalytic activity, selectivity, stability, and complete atom utilization. These catalysts involve isolated atoms supported on substrates without aggregating into nanoparticles. In this review, we elucidate the mechanisms and pathways of pNRR, focusing on the latest advances in carbon-based and non-carbon-based SMACs, and conclude with an overview of the existing challenges and prospects of pNRR for sustainable ammonia production.