Hydrogen Production via Methanol Steam Reforming over CuO/ZnO/Al2O3 Catalysts Prepared via Oxalate-Precursor Synthesis

Abstract

CuO/ZnO/Al2O3 catalysts are commonly used for the methanol steam reforming reaction. The oxalate precursor of CuO/ZnO/Al2O3 catalysts were prepared via the co-precipitation method using oxalic acid as the precipitator, deionized water and ethanol as the solvent, and microwave radiation and water baths as aging heating methods, respectively. This suggests that ethanol selects the crystalline phase composition of oxalate precursors and limits their growth. Microwave irradiation prompted the isomorphous substitution between Cu2+ of CuC2O4 and Zn2+ of ZnC2O4 in the mother liquid; Zn2+ in ZnC2O4·xH2O was substituted with Cu2+ in CuC2O4, forming the master phase (Cu,Zn)C2O4 in the precursor. Moreover, the solid solution Cu-O-Zn formed after calcination, which exhibited nano-fibriform morphology. It has the characteristics of small CuO grains, a large surface area, and strong synergistic effects between CuO and ZnO, which is conducive to improving the catalytic performance of methanol steam reforming. The conversion rate of methanol reached 91.2%, the space time yield of H2 reached 516.7 mL·g−1·h−1, and the selectivity of CO was only 0.29%.