Synergetic photocatalytic and thermocatalytic aqueous phase reforming of methanol for hydrogen production based on noble metal/photosensitive supports catalysts

To overcome high Gibbs free energy and low reaction rate of thermal catalytic and photocatalytic hydrogen production from methanol-H2O mixture, photo-thermal synergistic catalysis (PC-TC) reforming has proved to be an effective strategy owing to the photoassited thermal synergistic effect to accelerate the step controlling kinetic behavior. In order to efficiently produce H-2, proper photosensitive catalysts which absorb light energy and also show efficient thermal catalytic (TC) performance need to be developed. To study the designing principle for catalysts, herein we incorporate Pt/Pd and three different supports which show similar band gaps (ZnO, CeO2, and P25) through the in-situ photodeposition, which act as catalysts for PC-TC methanol aqueous reforming. The resultant 0.1%Pt/P25 catalyst exhibits H-2 evolution activity similar to 3.1 times than that of the TC condition and similar to 5.5 times than that of the photocatalytic reforming (PC) condition in the proposed PC-TC process; meanwhile 0.1%Pt/ZnO and 01%Pt/CeO2 under PC-TC condition show similar to 4.3 times and similar to 2.0 times than that of the catalytic performance under TC condition. The physical characterizations prove that the metal-support interaction and the supports may be key factors for the catalytic performance. The active intermediate trapping experiments demonstrate possible intermediates in the PC-TC process and established reaction mechanisms to explain the synergetic effect for improved efficiency of hydrogen production. These findings may open up a new avenue of designing catalysts based on semi-conductors for the PC-TC reforming of methanol-water to produce hydrogen in a high-efficiency and low-cost way, serving the needs of the future hydrogen economy. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.