Enhancement effect of gallium modified CuMgAl spinel on the production of high‐purity H ₂ by methanol steam reforming

Abstract In the hydrogen production technology from methanol steam reforming (MSR) as a hydrogen source for proton exchange membrane fuel cells (PEMFCs), the toxic effect of CO in the feed gas on the fuel cell is an important issue. In this study, Ga was innovatively introduced into Cu 0.75 Mg 0.25 Al 2 O 4 spinel to modify the hydrogen purity and low CO selectivity of the hydrogen source for hydrogen production. First, the different Ga doping content in B site was synthesized, and the properties of the catalysts were characterized by X‐ray powder diffractometer (XRD), scanning electron, microscope (SEM), energy dispersive spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), and brunner−emmet−teller (BET) techniques, as well as the MSR catalytic performance, was deeply explored. The SEM results indicate that the surface of Cu 0.75 Mg 0.25 Ga 0.2 Al 1.8 O 4 has a unique coagulation and stacking structure. BET analysis shows that it has a larger specific surface area. XPS results show the presence of oxygen vacancies. The reduction of CO production is attributed to the existence of oxygen vacancy, which improves the adsorption capacity of reactive oxygen species and promotes the migration of lattice oxygen. By optimizing of reaction conditions, including temperature, ratio of water and methanol (W/M), and liquid hourly space velocity on the catalytic performance, it was found that Cu 0.75 Mg 0.25 Ga 0.2 Al 1.8 O 4 has the best performance, with a methanol conversion rate as high as 100% and CO selectivity is 0. Furthermore, 50‐h stability test results indicate that Cu 0.75 Mg 0.25 Ga 0.2 Al 1.8 O 4 has good stability, and the CO selectivity was almost 0. This study states that the doping of Ga modifies the catalytic performance of CuMgAl spinel; therefore, the Cu 0.75 Mg 0.25 Ga 0.2 Al 1.8 O 4 synthesized in this article is a promising MSR catalyst that can provide a stable high concentration hydrogen source for PEMFC.