Nickel atoms of nickel foam simultaneously mediated charge redistribution and firm immobilization of zinc oxide for safe and efficient photocatalytic nitrogen oxide removal

Photocatalytic technology has emerged as a promising solution for air purification of ppb-level nitrogen oxides (NO x ), but potential risk of secondary pollution should not be overlooked, which could be triggered by the production of toxic intermediate and the potential release of airborne catalyst particles during reaction processes. Herein, nickel foam (NF) has been introduced as not only carrier material but also performance promoter for zinc oxide (ZnO). The NF supported ZnO sample (Ni-ZnO/NF) demonstrates multifunctional superiority: 66.4 % nitric oxide (NO) removal efficiency, <1.7 % nitrogen dioxide (NO 2 ) byproduct generation, and ultralow photocatalyst loss (<1.2 % mass). Mechanistic investigations combining experimental characterization and theoretical simulations reveal atomic substitution processes where NF-derived Ni atoms replace Zn sites in the ZnO lattice, forming stable Ni-O interfacial bonds, which contributes to enhance interaction between ZnO and NF for firm immobilization and form electron localization zones around Ni-O bond for reactants activation and reactive oxygen species formation. The optimized reaction pathway (NO + e −  → NO − , NO −  +  1 O 2  → NO 3 − ) ensures complete oxidation while suppressing hazardous intermediates. This work blueprints next-generation supported photocatalysts through atomic-level interface engineering, advancing practical application of photocatalytic technology for sustainable air purification.