Facile ball-milling synthesis of TiO2 modified ZnO for efficient photocatalytic removal of atmospheric nitric oxide gas under solar light irradiation

Highlights: • ZnO/TiO₂ is successfully fabricated by a facile ball-milling process. • Photocatalytic performance of ZnO/TiO₂ is 1.4 times higher than that of commercial TiO₂. • ZnO/TiO₂ decreased drastically NO₂ conversion yield from 12.78% to 7.18%. • Photogenerated holes play an essential role in the NO photocatalytic reaction of ZnO/TiO₂. In this study, ZnO/TiO₂ composite is synthesized by a facile ball-milling process. The X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) results of the composite sample indicate all properties of the two-component original materials including ZnO and TiO₂. The as-prepared ZnO/TiO₂ composite shows the highest photocatalytic nitric oxide (NO) oxidation efficiency under solar light irradiation which is higher than 2.8 times compared to pure ZnO nanoparticles (NPs). Especially, the NO₂ conversion yield is decreased drastically from 12.78% to 7.18% when ZnO/TiO₂ composites are used as a photocatalyst for the atmospheric NO gas removal under solar light. In addition, the photocatalytic NO removal performance of the ZnO/TiO₂ composite is still high 33.17% and all the characteristic peaks and bonds remain in the material after many recycles.