The Influence of ZnO−ZrO₂ Interface in Hydrogenation of CO₂ to CH₃OH

The influence of the interface in ZnO−ZrO₂ catalysts for the selective hydrogenation of CO₂ to CH₃OH is investigated. Specifically, we perturbed its structure using two different synthetic methods: surface organometallic chemistry (SOMC) and flame-spray pyrolysis (FSP) and investigated the speciation of the resulting materials by spectroscopic techniques, such as XAS, NMR, IR, UV-Vis, and EPR. The results indicate that oxidic Zn particles that co-exist with ZrO₂, as synthesized by FSP, show a superior selectivity in contrast to Zn(0) nanoparticles or Zn(II) single sites on ZrO₂, formed using SOMC. Further experiments underlined the importance of the ZnO−ZrO₂ interface in the process: only materials with such an interface exhibit highly selective production of CH₃OH, proceeding likely via the formation of the surface CH₃O intermediates.