Synergetic photocatalytic and thermocatalytic reforming of methanol for hydrogen production based on Pt@TiO2 catalyst

In order to efficiently produce H2, conventional methanol-water thermocatalytic (TC) reforming requires a very high temperature due to high Gibbs free energy, while the energy conversion efficiency of methanol-water photocatalytic (PC) reforming is far from satisfaction because of the kinetic limitation. To address these issues, herein, we incorporate PC and TC processes together in a specially designed reactor and realize simultaneous photocatalytic/thermocatalytic (PC-TC) reforming of methanol in an aqueous phase. Such a design facilitates the synergetic effect of the PC and TC process for H2 production due to a lower energy barrier and faster reaction kinetics. The methanol-water reforming based on the optimized 0.05%[email protected]2 catalyst delivers an outstanding H2 production rate in the PC-TC process (5.66 μmol H2·g–1 catalyst·s–1), which is about 3 and 7 times than those of the TC process (1.89 μmol H2·g–1 catalyst·s–1) and the PC process (0.80 μmol H2·g–1 catalyst·s–1), respectively. Isotope tracer experiments, active intermediate trapping experiments, and theoretical calculations demonstrate that the photo-generated holes and hydroxyl radicals could enhance the methanol dehydrogenation, water molecule splitting, and water-gas shift reaction, while high temperature accelerates reaction kinetics. The proposed PC-TC reforming of methanol for hydrogen production can be a promising technology to solve the energy and environmental issue in the closed-loop hydrogen economy in the near future.