Modulation of electron delocalization and localization induced by single-atom alloys on defective HxMoO3−y for boosting photocatalytic reduction of nitric oxide to ammonia

Photocatalytic technology for the NO reduction has tremendous potential at ambient conditions compared to conventional NO abatement technologies. Modulation of delocalization and localization of photogenerated electrons is crucial in photocatalysis, yet remains a grand challenge. Here we report a strategy involving PdCu single-atom alloys (SAAs) on HxMoO3−y that drives photocatalytic NO reduction toward NH3 with 100% selectivity, a high yield rate of 28.2 mmol gcat−1 h−1, and a total NH3 yield of 24.3 mmol within 120 h, which shows a prominent advantage in the area of photocatalytic NO reduction to NH3 at ambient conditions. Detailed experiments and characterizations combined with theoretical calculations demonstrate that (1) the paired Pd–Cu sites as highly active centers contribute local d-orbitals electrons to NO for NH3 synthesis and facilitate the formation of HNO∗; (2) the sufficient delocalized electrons induced by plasmon resonances of HxMoO3−y can further replenish the depleted d-orbitals electrons in PdCu SAAs. Importantly, the well-retained performance of photocatalyst for NO removal in simulated flue gases demonstrates huge potential for its industrial application.