Preparation, characterization, and catalytic activity of H5PMo10V2O40 immobilized on nitrogen-containing mesoporous carbon (PMo10V2/N-MC) for selective conversion of methanol to dimethoxymethane

Nitrogen-containing mesoporous carbon (N-MC) 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 a site for the immobilization of [PMo₁₀V₂O₄₀]⁵⁻. By taking advantage of the overall negative charge of [PMo₁₀V₂O₄₀]⁵⁻, H₅PMo₁₀V₂O₄₀ (PMo₁₀V₂) catalyst was chemically immobilized on the N-MC support as a charge-matching component. Characterization results showed that nitrogen in the N-MC played an important role in forming a nitrogen-derived functional group (amine group), and PMo₁₀V₂ catalyst was finely and chemically immobilized on the nitrogen-derived functional group of N-MC support. In the vapor-phase selective conversion of methanol, the PMo₁₀V₂/N-MC catalyst showed a higher conversion of methanol than the bulk PMo₁₀V₂ catalyst. Furthermore, the PMo₁₀V₂/N-MC catalyst showed a higher selectivity for dimethoxymethane (a product formed by bifunctional oxidation-acid-acid catalysis) and a higher selectivity for methylformate (a product formed by bifunctional oxidation-acid-oxidation catalysis) than the PMo₁₀V₂ catalyst. Reaction pathway for selective conversion of methanol to dimethoxymethane over PMo₁₀V₂/N-MC catalyst could be controlled by changing the methanol feed rate.