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 H x MoO 3−y that drives photocatalytic NO reduction toward NH 3 with 100% selectivity, a high yield rate of 28.2 mmol h −1 , and a total NH 3 yield of 24.3 mmol within 120 h, which shows a prominent advantage in the area of photocatalytic NO reduction to NH 3 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 NH 3 synthesis and facilitate the formation of HNO*; (2) the sufficient delocalized electrons induced by plasmon resonances of H x MoO 3−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. • PdCu single-atom alloys on H x MoO 3−y is used for photocatalytic NORR to NH 3 . • Efficient and robust NH 3 production has been achieved at ambient conditions. • Pd-Cu sites as highly active centers contribute d-orbitals electrons to NO for NH 3 synthesis. • Delocalized electrons from H x MoO 3−y replenish the depleted d-orbitals electrons in SAAs.