A Bi/BiOI/(BiO)2CO3 heterostructure for enhanced photocatalytic NO removal under visible light

Abstract Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, oxygen vacancies, Bi particles, and Bi 2 O 2 CO 3 were co-induced in BiOI via a facile in situ assembly method at room temperature using NaBH 4 as the reducing agent. In the synthesized ternary Bi/BiOI/(BiO) 2 CO 3 , the oxygen vacancies, dual heterojunctions (i.e., Bi/BiOI and BiOI/(BiO) 2 CO 3 ), and surface plasmon resonance effect of the Bi particles contributed to efficient electron-hole separation and an increase in charge carrier concentration, thus boosting the overall visible light photocatalysis efficiency. The as-prepared catalysts were applied for the removal of NO in concentrations of parts per billion from air in continuous air flow under visible light illumination. Bi/BiOI/(BiO) 2 CO 3 exhibited a highly enhanced NO removal ratio of 50.7%, much higher than that of the pristine BiOI (1.2%). Density functional theory calculations and experimental results revealed that the Bi/BiOI/(BiO) 2 CO 3 composites promoted the production of reactive oxygen species for photocatalytic NO oxidation. Thus, this work provides a new strategy to modify narrow-band semiconductors and explore other bismuth-containing heterostructured visible-light-driven photocatalysts.