Active Site Synergy of Rh and Co Derived from ZrO2-Supported LaRhXCo1-XO3 Perovskite Nanostructures for the Direct Synthesis of Ethanol from Syngas

The catalytic synthesis of ethanol directly from syngas is one of the most attractive routes due to its cost-effectiveness and the high demand for ethanol. However, progress is critically stagnant due to the limited activity and ethanol selectivity of the catalysts. Here, La-Rh-Co/ZrO2 nanoscaled catalysts derived from ZrO2-supported LaRhxCo1-xO3 perovskite nanostructures were prepared by citric acid complexing followed by calcination and reduction. Rh and Co species derived from the precursors can increase the amount of interfacial species and construct the active sites for the direct synthesis of ethanol from syngas. Co species were proven to be confined in the ZrO2 matrix, with high-valent Co delta+ derived from LaCoOx. These Co species can decorate Rh species by forming an interface, Rh0-Rh+-O-Co delta+, as confirmed by extended X-ray absorption fine structure, resulting in a higher molar fraction of Rh+. The formed intimate Rh0-Rh+- O-Co delta+ active sites originating from the interfaces are conducive to CO dissociation and CO insertion, leading to an impressive ethanol selectivity of 55.7% and a high CO conversion of 33.5% with good stability over the La-Rh-Co/ZrO2 nanoscaled catalysts. The results show that the strategy of interfacial construction enables the design of robust catalysts to break the scale relationship between conversion and selectivity.