Photocatalytic NO degradation often suffers from sluggish charge carrier separation and low selectivity. Herein, a series of In2O3/TiO2 (P25) composites were synthesized to enhance NO abatement. Benefiting from the conspicuous synergistic effect between In2O3 and P25, the In2O3/P25 catalysts demonstrated more than double the NO elimination performance compared to pure P25 and In2O3. The In2O3/P25 sample with 75 wt% In2O3 (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. ·O2− 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 In2O3, facilitated the targeted deep oxidation of trace NO into NO3− rather than harmful NO2. This work discloses a promising strategy for the efficient removal of NO from the atmosphere by reducing the emission of hazardous intermediate NO2.
Read full abstract