Structure-activity relationships of zirconium-modified copper-based catalysts during methanol steam reforming

Abstract

Acknowledged as an ideal method for in situ hydrogen generation, methanol steam reforming (MSR) requires high-performance catalysts to enhance production efficiency. Herein, we prepared a series of Zr-modified Cu-based catalysts by a coprecipitation method and conducted a systematic analysis of the impacts of structural variations on MSR performance. Extensive characterization reveals a strong dependence of the catalyst’s surface structure on Zr content. Introducing a moderate amount of Zr to the Cu/ZnO catalysts forms ZnZrO_x solid solution and increases Cu dispersion, forming more Cu-ZnZrO_x and Cu-ZnO interfacial sites with higher H₂ production rate. Further increases in Zr content enlarge Cu nanoparticles and multiply Cu-ZrO₂ interfacial sites. The optimal catalyst with a Zn/Zr molar ratio of 5, with the richest Cu-ZnO/Cu-ZnZrO_x interfacial sites, achieves the highest H₂ production rate of 117.4 ${\text{mmol}}_{{\text{H}}_{\text{2}}}{\text{g}}_{\text{cat}}^{\text{-1}}{\text{h}}^{\text{-1}}$ at 200 °C, which is 1.3 times and 6.8 times higher than those of Cu/ZnO and Cu/ZrO₂, respectively.