Efficient Visible Light Photocatalytic Oxidation of NO on Aerosol Flow-Synthesized Nanocrystalline InVO4 Hollow Microspheres

In this study, aerosol flow-synthesized (AFS) nanocrystalline InVO4 hollow microspheres (AFS-InVO4) were used to oxidize gaseous NO at indoor air level under visible light and compared with hydrothermally synthesized InVO4 counterpart powder. Results revealed that the AFS-InVO4 hollow spheres exhibited higher photocatalytic activity than the hydrothermally synthesized counterpart. The photocatalytic activity enhancement could be attributed to the large surface area and special hollow structures, which were favorable for the diffusion of intermediates and the deactivation inhibition of photocatalyst during the photocatalytic reaction. Fourier transform infrared spectroscopy results confirmed the generation of nitric acid on the AFS-InVO4 surface during the photocatalysis of NO in the gas phase, suggesting that the oxidation of NO molecules was the major process in this photocatalytic reaction. Multiple runs of the photocatalytic NO removal revealed that the AFS-In VO4 hollow spheres were very stable during photocatalysis. This study presents a promising approach for scaling up industrial production of InVO4 hollow spheres with improved photocatalytic activity for indoor air purification.