Preparation of H₅PMo₁₀V₂O₄₀ (PMo₁₀V₂) catalyst immobilized on nitrogen-containing mesoporous carbon (N-MC) and its application to the methacrolein oxidation

Nitrogen-containing mesoporous carbon (N-MC) with high surface area (=938 m²/g) and large pore volume (0.99 cm³/g) was synthesized by a templating method using SBA-15 and polypyrrole as a templating agent and a carbon precursor, respectively. The N-MC was then modified to have a positive charge, and thus, to provide sites for the immobilization of the H₅PMo₁₀V₂O₄₀ (PMo₁₀V₂) catalyst. By taking advantage of the overall negative charge of [PMo₁₀V₂O₄₀]^5-, the PMo₁₀V₂ catalyst was immobilized on the N-MC support as a charge matching component. The prepared PMo₁₀V₂/N-MC catalyst was applied to the vapor-phase oxidation of methacrolein (a model surface-type reaction). It was found that the [PMo₁₀V₂O₄₀]^5- species were finely and chemically immobilized on the N-MC support as charge matching species. In the vapor-phase oxidation of methacrolein, the PMo₁₀V₂/N-MC catalyst showed a higher conversion of methacrolein and a higher yield for methacrylic acid than the unsupported PMo₁₀V₂ catalyst. Furthermore, the PMo₁₀V₂/N-MC catalyst also showed a higher conversion of methacrolein and a higher yield for methacrylic acid than the PMo₁₀V₂/SBA-15 catalyst prepared by an impregnation method. The enhanced catalytic performance of PMo₁₀V₂/N-MC in the model surface-type reaction was due to the fine dispersion of PMo₁₀V₂ species formed via chemical immobilization.