Direct Photocatalytic Methane Oxidation to Formaldehyde by N Doping Co-Decorated Mixed Crystal TiO.

In this paper, N-doped TiO mixed crystals are prepared via direct calcination of TiN for highly selective oxidation of CH to HCHO at room temperature. The structures of the prepared TiO samples are characterized to be N-doped TiO of anatase and rutile mixed crystals. The crystal structures of TiO samples are determined by XRD spectra and Raman spectra, while N doping is demonstrated by TEM mapping, ONH inorganic element analysis, and high-resolution XPS results. Significantly, the production rate of HCHO is as high as 23.5 mmol·g·h with a selectivity over 90%. Mechanism studies reveal that HO is the main oxygen source and acts through the formation of ·OH. DFT calculations indicate that the construction of a mixed crystal structure and N-doping modification mainly act by increasing the adsorption capacity of HO. An efficient photocatalyst was prepared by us to convert CH to HCHO with high yield and selectivity, greatly promoting the development of the photocatalytic CH conversion study.