Highly Effective Copper-Ceria Catalysts for Co-Free Hydrogen Production in Methanol Steam Reforming

To prepare supported catalysts with distinct structures for identifying active metals is a crucial challenge in heterogeneous catalysis. Here we report the fabrication of copper-ceria catalysts that contains different copper species by adjusting the metal loading content and leaching. Using the methanol steam reforming (MSR) for hydrogen production as probe reaction, it is H2 and CO2 rather than CO can be detected for each catalyst. It means that these catalysts achieve CO-free H2 production from 200 to 350 °C, which is of potential use for proton exchange membrane fuel cells (PEMFC). The H2 production rate of 5CuCe is as high as 53.8 mLH2×gcat-1×min-1 at 250 °C, much higher than that of other reported copper-ceria catalysts whose Cu loading is close to or ahead of 5 wt%. Based on the precise and integrated characterizations, the separated CuO nanoparticles in the 50CuCe catalyst are useless for catalysis on account of the similar activity to the leached one. By contrast, both highly dispersed CuOx clusters and Cu−[Ox]−Ce structures possibly contribute to CO-free H2 production.