Light‐Induced Dynamic Stability of Oxygen Vacancies in BiSbO₄ for Efficient Photocatalytic Formaldehyde Degradation

Abstract

Defect engineering has been regarded as a versatile strategy to maneuver the photocatalytic activity. However, there are a few studies concerning how to maintain the stability of defects, which is important to ensure sustainable photocatalytic performance. Here, a novel strategy to modulate the structural properties of BiSbO4 using light‐induced dynamic oxygen vacancies is reported by us for efficient and stable photocatalytic oxidation of formaldehyde. Interestingly, the continuous consumption and replenishment of vacancies (namely dynamic vacancies) ensure the dynamic stability of oxygen vacancies, thus guaranteeing the excellent photocatalytic stability. The oxygen vacancies could also accelerate the electron migration, inhibit the photogenerated electron/hole recombination, widen the light absorption spectra, and thus improve the photocatalytic formaldehyde removal performance. Combined with the results of in situ DRIFTS, the reaction mechanism for each step of formaldehyde oxidation is revealed. As supported by DFT calculation of Gibbs free energy, the introduction of oxygen vacancies into BiSbO4 can promote spontaneous process of formaldehyde oxidation. Our work highlights a promising approach for stabilizing the defects and proposes the photocatalytic reaction mechanism in combination with the thermodynamic functions.

Shining light on ZnIn2S4 photocatalysts: Promotional effects of surface and heterostructure engineering toward artificial photosynthesis

“…), with point defects such as vacancy and doping frequently found in the recent studies of ZnIn 2 S 4 ‐based semiconductor photocatalyst. In general, defect engineering manifests its potential in light absorption modifications, charge separation promotion, as well as stable surface reaction facilitation 82,83 . Moreover, modifying semiconductor photocatalysts by introducing defects can reconstruct a new energy level with narrower bandgap, leading to enhanced visible light activity 84 .…”

“…In general, defect engineering manifests its potential in light absorption modifications, charge separation promotion, as well as stable surface reaction facilitation. 82,83 Moreover, modifying semiconductor photocatalysts by introducing defects can reconstruct a new energy level with narrower bandgap, leading to enhanced visible light activity. 84 Defects can also function as a reactant adsorption site, in addition to the acceleration of charge carriers transportation from photocatalyst to the adsorbed reactants to prohibit charge recombination, given if the amount of defects is well controlled.…”

Optimizing the Gas–Solid Photocatalytic Reactions for Air Purification

“…Meanwhile, enhancing the stability of vacancies is the key to ensure the sustainability of photocatalytic performance since vacancies are easy to be occupied by reactants, giving rise to the deactivation of photocatalyst. Ran et al revealed that OVs tended to be filled by oxygen molecules in the air during photocatalytic oxidation, leading to the decrease of OVs concentration and the deactivation of photocatalyst. , Correspondingly, light-induced dynamic OVs was proposed, and the continuous consumption and replenishment of vacancies ensured the dynamic stability of OVs, thus guaranteeing the accelerated activation of reactants and charge separation-transformation for excellent photocatalytic stability. Furthermore, although insulators display a large band gap and inert photocatalytic efficiency, photoexcited electron transitions were also realized after the introduction of a middle energy level via specific vacancies.…”

Photocatalytic nitrogen reduction to ammonia: Insights into the role of defect engineering in photocatalysts

“…A variety of techniques have been attempted to determine the amount of NH3 produced during nitrogen photoreduction reaction and can be mainly divided into six types, including (1) spectrophotometry (or colorimetry), (2) ion chromatography (IC), (3) ion-selective electrode (ISE), (4) fluorescence, (5) 1 H NMR spectroscopy, and (6) ultrahigh performance liquid chromatography-mass spectrometry (UPLC-MS) [108,109]. Currently, photocatalytic nitrogen reduction studies are heavily reliant on the spectrophotometric/colorimetric methods using indophenol blue [110] and Nessler's reagents [111].…”

“…Light irradiation enables one to create defects in some semiconductors during a photocatalytic process [108,178,179]. Creation of OVs on the surface of Bi5O7Br nanotubes was observed upon visible-light photoirradiation [180,181].…”