The role of copper crystallization and segregation toward enhanced methanol synthesis via CO2 hydrogenation over CuZrO2 catalysts: A combined experimental and computational study

Abstract

The role of copper crystallization in the enhanced methanol production via CO2 hydrogenation over CuZrO2 catalysts was explored along with a combination of experimental and computational studies. The catalysts were synthesized by a surfactant-assisted route followed by reflux in a one-pot method. Catalyst structure, bulk properties, surface reactivity, and reaction pathways were evaluated by XRD, BET, FRX, TPR, N2O-TPD, CO2-TPD, in situ DRIFTS, AP-XPS, and XRD. Calculations based on density functional theory (DFT) were performed to explore the formation of possible intermediates in a copper-driven conversion with surface models of the CuZrO2 catalyst. The combination of experiments and DFT results revealed that the intermediate steps of the catalyzed reaction of CO2 hydrogenation into methanol might depend on the incorporation of Cu in the zirconia sample. The catalyst containing only amorphous interfacial sites showed higher performance on CO2-to-methanol hydrogenation compared to the catalysts containing high crystallinity of copper. The superior activity of the 10CuZrO2 catalyst is mainly ascribed to the cooperative effect between the highly dispersed copper nanoparticles and the basic sites.