The use of single metal atoms-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. A prospective alternative to the Haber-Bosch process is the photocatalytic reduction nitrogen (pNRR), allowing NH3 production under room conditions. The optimization of photocatalysts, particularly through the use of single metal atom catalysts, plays a significant role in enhancing the performance of pNRR. Single metal atom catalysts offer adjustable catalytic performance and improved selectivity, making them a viable strategy for pNRR. Research has demonstrated that carbon-based and metal-based matrices effectively disperse highly active single atoms, enhancing pNRR efficiency. This review delves into utilizing atomically dispersed single atoms in pNRR on various supporters, examining theoretical frameworks and experimental findings. The review is structured into 4 sections: elucidating the mechanism and pathway of pNRR, highlighting the use of single metal atom catalysts (SMACs) where metal atoms are dispersed on carbon substrates for pNRR, showcasing SMACs with metal atoms dispersed on non-carbon substrates for pNRR, and concluding with an overview of the existing challenges and prospects of pNRR for sustainable ammonia production.