A series of catalysts with different contents of P-Mo-V mixed oxide supported on SBA-15 have been prepared by an impregnation method using H₅PMo₁₀V₂O₄₀ (HPA) as a precursor. The effects of P-Mo-V mixed oxide loading, reaction temperature and space velocity (GHSV) on the catalytic performance of selective oxidation of methane were investigated. The results indicate that the catalysts exhibit high selectivity to HCHO. CH₄ conversion increases with increasing the loading of P-Mo-V mixed oxide and reaction temperature. The selectivity to HCHO reaches a maximum at certain loading of P-Mo-V mixed oxide. A space time yield of 295 g•kg_cat^－1•h^－1 was obtained over the catalyst of 2.89PMoV/SBA-15 under the optimum condition of 640 ℃ and GHSV of 48300 L•kg^－1•h^－1. The characterization results of the catalysts suggest that the P-Mo-V mixed oxides with the mass loading ≤2.89% are highly dispersed in the channels of SBA-15. The oxides with weak acidity and low reduction temperature are favorable to the selective oxidation of CH₄ to HCHO.

Key words: H₅PMo₁₀V₂O₄₀, SBA-15, methane, selective oxidation, formaldehyde