Confinement of Cu2O by in-situ derived NH2-MIL-125@TiO2 for synergetic photothermal-driven hydrogen evolution from aqueous-phase methanol reforming

Abstract

Photothermal synergism can effectively activate methanol at low operating temperature and significantly reduce the activation energy of the reaction, achieving more efficiently H2 release from methanol reforming. Here, a novel hierarchical heterojunction that integrating photo- and thermal-active Cu2O catalytic species with in-situ derived NH2-MIL-125@TiO2 framework was specifically designed for photothermal-driven aqueous phase reforming of methanol into H2. The afforded Cu2O/NH2-MIL-125@TiO2 realized an outstanding photothermal H2 production activity (apparent quantum efficiency of 22.3 % at 365 nm), ca. 13-times higher than that of thermocatalytic condition. Interestingly, the photothermal effect did confer the Cu2O/NH2-MIL-125@TiO2 with unexpected activity at low temperature subsided to 100 °C and accelerated the activation of MeOH/H2O with an obvious reduction of activation energy from 82.62 kJ·mol−1 to 52.40 kJ·mol−1.The improvement of catalyst stability and the promotion of charge separation also contributed to a long-term photothermal H2 evolution activity with average rate of 1.49x106 μmolgCu-1h−1 and a total turnover number (TON) up to 5971 in 63 h, almost 125-fold promotion compared with Cu2O.