Type-II heterojunction In2O3/TiO2 with highly efficient charge separation for boosted photocatalytic NO abatement

Photocatalytic NO degradation often suffers from sluggish charge carrier separation and low selectivity. Herein, a series of In 2 O 3 /TiO 2 (P25) composites were synthesized to enhance NO abatement. Benefiting from the conspicuous synergistic effect between In 2 O 3 and P25, the In 2 O 3 /P25 catalysts demonstrated more than double the NO elimination performance compared to pure P25 and In 2 O 3 . The In 2 O 3 /P25 sample with 75 wt% In 2 O 3 (In-P25-75) achieved a NO removal efficiency of 51.7 %, higher than reported catalysts (30.0–49.0 %). It was the successful formation of type-II heterostructure that enabled intimate interfacial contact and provided ample electron transfer channels. Moreover, photoluminescence spectra and photoelectrochemical measurement confirmed the improved separation and inhibited recombination of photogenerated charge carriers in In-P25-75, thereby boosting the NO photocatalytic efficiency. ·O 2 − and ·OH radicals generated by photoinduced electron transfer to the conduction band of P25, along with the induced holes confined to the valence band of In 2 O 3 , facilitated the targeted deep oxidation of trace NO into NO 3 − rather than harmful NO 2 . This work discloses a promising strategy for the efficient removal of NO from the atmosphere by reducing the emission of hazardous intermediate NO 2 .