Simultaneous introduction of oxygen vacancies and Bi metal onto the {001} facet of Bi3O4Cl woven nanobelts for synergistically enhanced photocatalysis

Abstract

In order to relieve air pollution problems via photocatalytic NO purification, we prepared Bi₃O₄Cl (BOC) woven nanobelts with exposed {001} facets by a one-pot hydrothermal method. The as-prepared catalysts were modified by a simple chemical reduction to introduce oxygen vacancies (OVs) and plasmonic Bi metal on their surfaces. The photocatalytic performance was strongly dependent on the OVs and surface plasmon resonance (SPR) effect induced by Bi metal. DFT calculations and in situ DRIFTS study were closely combined to show that the OVs could not only induce the formation of a middle-gap in BOC which increases the production of the ˙OH species by introducing more holes on the valence band, but also promote the generation of ˙O₂⁻ species by activating the adsorbed O₂ on the surface. Meanwhile, the Bi metal can serve both as an electron donor and a bridge for charge transfer to promote charge separation. As a result, the OVs and Bi metal could synergistically tailor the charge transfer pathway and enhance the photocatalytic performance significantly. Moreover, the reaction intermediates were revealed and the mechanism of photocatalytic NO oxidation was proposed based on in situ DRIFTS spectra. The design concept of modifying the catalyst surface via simultaneous introduction of OVs and Bi metal on the catalyst surface could offer a novel strategy to enhance the photocatalytic performance of other nanomaterials for environmental and energy-related applications.