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

Abstract

<jats:p>Ammonia (NH<jats:sub>3</jats:sub>) 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<jats:sub>3</jats:sub> synthesis method under ambient conditions. Nitrate (NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup>) emerges as a compelling nitrogen source due to its numerous advantages over inert nitrogen (N<jats:sub>2</jats:sub>) gas, such as its relatively low dissociation energy and high aqueous solubility. Moreover, NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup> is a common contaminant found in wastewater, posing a threat to aquatic ecosystems. The photocatalytic NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup> reduction to NH<jats:sub>3</jats:sub>, 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<jats:sub>3</jats:sub><jats:sup>−</jats:sup> to NH<jats:sub>3</jats:sub> conversion. The mechanism behind the conversion of NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup> to NH<jats:sub>3</jats:sub> is briefly explained, and photocatalysts exhibiting high selectivity and activity in NH<jats:sub>3</jats:sub> 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<jats:sub>3</jats:sub> production via NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup> reduction.</jats:p>