Lawrence Berkeley National Laboratory

On Cu/ZrO2 catalysts, variation of the Cu loading from 0.2 wt% to 80 wt% allows assessing the influence of the Cu-ZrO2 interface on the methanol steam reforming (MSR) performance by steering Cu particle size and morphology, revealing the contribution of potential active sites at the interface and the intrinsic relative contributions of the support and Cu surface fraction. As ZrO2 influences both CO2-selective and selectivity-spoiling MSR reaction channels, disentangling support-specific effects from the special phase-boundary reactivity and the intrinsic Cu° reactivity is possible by our approach. By choosing a broad range of Cu loadings, a comparison of the most extreme cases of strong predominance of bulk-like Cu sites (80 wt% Cu) vs. highly dispersed Cu (0.2 wt%), dominated by interfacial and support reactivity, becomes accessible. Cu (80 wt%)/ZrO2 evolves as the best MSR catalyst by avoiding adverse support effects and providing a high number of support-wetting bulk-like Cu sites.