Present State and Future Outlook of Ammonia Production through Photocatalytic Nitrate Reduction

Ammonia (NH 3 ) production has gained increasing attention owing to its versatility in both industrial and agricultural applications, as well as its potential as a next‐generation energy carrier with a high hydrogen density. Given the energy‐intensive and environmentally impactful nature of the Haber–Bosch process, there is a pressing need for a sustainable NH 3 synthesis method under ambient conditions. Nitrate (NO 3 − ) emerges as a compelling nitrogen source due to its numerous advantages over inert nitrogen (N 2 ) gas, such as its relatively low dissociation energy and high aqueous solubility. Moreover, NO 3 − is a common contaminant found in wastewater, posing a threat to aquatic ecosystems. The photocatalytic NO 3 − reduction to NH 3 , which utilizes sunlight to convert contaminants into value‐added chemicals, aligns perfectly with the need for sustainable solutions. This perspective reviews the latest advancements in the field of photocatalytic NO 3 − to NH 3 conversion. The mechanism behind the conversion of NO 3 − to NH 3 is briefly explained, and photocatalysts exhibiting high selectivity and activity in NH 3 production, along with other influential factors, are summarized. Additionally, current challenges and future prospects within this field are discussed.This perspective will provide a valuable guidance for future research in the realm of photocatalytic NH 3 production via NO 3 − reduction.