Bi metal prevents the deactivation of oxygen vacancies in Bi2O2CO3 for stable and efficient photocatalytic NO abatement

Surface oxygen vacancies can normally enhance photocatalytic activity, but also easily suffers from instability and deactivation in continuous photocatalytic purification of air pollutants. Therefore, it is necessary to develop an effective method to improve the photocatalytic stability of oxygen vacancies. In this work, Bi metal nano particle decorated Bi2O2CO3 nanosheets with oxygen vacancy (Bi@OV-BOC) are fabricated and exhibited higher photocatalytic activity and stability than Bi2O2CO3 with oxygen vacancy (OV-BOC). The co-effect of Bi metal nanoparticles and oxygen vacancies could also effectively inhibit the formation of toxic intermediates (NO2) and promote it to form final products (NO3-). First-principles density functional theory (DFT) calculation and experimental results suggested that the co-effects of Bi metal nanoparticles and oxygen vacancies (OVs) can largely promote the separation and transfer of photo-generated electron and hole to generate abundant active radicals. More importantly, the Hi metal nanoparticles could be as the active site to activate O-2 and H2O molecules so that the O-2 and H2O molecules would not fill into oxygen vacancies, resulting in preventing the deactivation of oxygen vacancies. The sufficient active radicals can realize complete oxidation of intermediates into final products and avoid toxic intermediates (e.g. NO2) accumulation. This study reveals the co-effects of Bi and OVs in defective photocatalyst, and also provides fundamental guidance for maintaining the active role of oxygen vacancies.