Immobilization of H3PMo12O40 catalyst on the nitrogen-containing mesoporous carbon and its application to the vapor-phase 2-propanol conversion reaction

Abstract

Nitrogen-containing mesoporous carbon (N-MC) with high surface area (=1,115 m2/g) and large pore volume (=1.18 cm3/g) was synthesized by a templating method. The surface of N-MC was then modified to form a positive charge, and thus, to provide sites for the immobilization of [PMo12O40]3−. By taking advantage of the overall negative charge of [PMo12O40]3−, H3PMo12O40 (PMo12) was chemically immobilized on the N-MC support as a charge matching component. It was found that the PMo12/N-MC still retained relatively high surface area (=687 m2/g) and large pore volume (=0.67 cm3/g) even after the immobilization of PMo12. It was also revealed that PMo12 species were finely and molecularly dispersed on the N-MC support via chemical immobilization. In the vapor-phase 2-propanol conversion reaction, the PMo12/N-MC showed a higher conversion than the unsupported PMo12. Furthermore, the PMo12/N-MC showed an enhanced oxidation catalytic activity and a suppressed acid catalytic activity compared to the unsupported PMo12. This catalytic behavior of PMo12/N-MC was due to the molecular dispersion of PMo12 on the N-MC support formed via chemical immobilization by sacrificing the proton.