Bimetallic Pt–Pd catalysts supported on TiO2 for enhanced photocatalytic N-alkylation of amines with alcohols: the synergistic effect

Pt–Pd alloy nano-catalysts supported on TiO2 were developed to enable efficient light-induced photocatalytic N-alkylation of amines with alcohols. Various techniques such as BET, XRD, XPS, HRTEM, UV-vis DRS, and PL analysis were utilized to characterize the catalysts. The photocatalytic mechanism was discussed based on observation as well as theoretical calculation. It was found that Pt serves as a hydrogen shuttle, extracting hydrogen from alcohols to Pd for subsequent hydrogenation on the Pd site. By changing the Pd/Pt ratio, it is feasible to tune the reaction rates of methanol dehydrogenation and imine hydrogenation simultaneously, resulting in an efficient N-alkylation reaction. As a result, the optimum catalyst Pd1Pt1/TiO2 exhibits excellent catalytic performance which is superior to the previously reported ones in terms of both the catalytic efficiency and the production capacity.