Fe(iii) cluster-grafted (BiO)2CO3 superstructures: in situ DRIFTS investigation on IFCT-enhanced visible light photocatalytic NO oxidation

Abstract

Fe(III) clusters were facilely grafted on the surface of (BiO)₂CO₃ (BC) hierarchical superstructures by soaking the BC in Fe(NO₃)₃ aqueous solution. The presence of Fe (III) clusters was confirmed with HRTEM, XPS and UV-vis DRS. The ESR trapping result revealed that the ˙OH radicals are the dominant reactive species responsible for photocatalytic NO oxidation. The production of ˙OH radicals was significantly promoted by the Fe(III) clusters due to the enhanced charge separation. The Fe(III) cluster-grafted BC displayed a highly enhanced visible light photocatalytic performance due to the direct interfacial charge transfer (IFCT) from BC to the Fe clusters. The Fe(III) cluster-grafted BC also demonstrated high photochemical and structural stability during multiple runs. A new visible light induced photocatalysis mechanism over Fe(III) cluster-grafted BC involving an IFCT process was firstly proposed. The in situ DRIFTS investigation revealed that the adsorbed NO could react with the dominant ˙OH radicals and generate the final products NO₂⁻ and NO₃⁻via the production of the intermediate NO₂, NO₂⁺ and NO⁺ species. The perspective of enhancing photocatalysis via IFCT could provide a new avenue for the modification of other efficient photocatalysts for enhanced performance.