Tailoring atomically dispersed Fe-induced oxygen vacancies for highly efficient gas-phase photocatalytic CO2 reduction and NO removal with diminished noxious byproducts

Single-atom-supported metal oxides have attracted extensive interest in energy catalysis, offering a promising avenue for mitigating greenhouse gas emissions and environmental pollution. This study presents a facile synthesis of single-atom Fe-modified Bi2WO6 photocatalysts. By carefully tuning the Fe ratios, the 1.5Fe-Bi2WO6 sample demonstrates exceptional photocatalytic efficiency in CO2 to CO reduction (36.78 μmol g−1). Additionally, an outstanding NO removal performance is also achieved through this photocatalyst with an impressively low conversion of toxic NO2 at just 0.37%. The reaction intermediates and mechanisms governing the photocatalytic reduction of CO2 into CO are elucidated using in situ DRIFTS and in situ XAS techniques. Regarding NO removal, the introduction of Fe single-atoms, along with induced oxygen vacancies, plays a pivotal role in facilitating the transformation of NO and NO2 into nitrate by stabilizing NO and NO2 species. Mechanistic insights into photocatalytic NO oxidation are garnered through scavenger trapping and EPR experiments employing DMPO. This study emphasizes single-atom-supported metal oxide's potential in sustainable chemistry and air purification, providing a promising solution for urgent environmental challenges.