Construction of Enriched Metal Vacancies to Enhance Catalytic Behavior for Selective Hydrogenation Over Au–Cu Nanoalloys

Hydrogenation of unsaturated C≡C groups is a promising way to realize ethylene purification in petrochemical processes and produce value-added products. Gold catalysts are known to exhibit satisfactory selectivity toward olefins. However, it still remains a grand challenge to improve the activity and inhibit the heavy coke effect while balancing the selectivity. This article describes the construction of Cu vacancies at an abrupt surface over a Au–Cu alloy catalyst to effectively promote the activation and dissociation of hydrogen, thereby reducing the activation energy barrier. More importantly, the generation of abundant Cu vacancies contributes to the electronic interaction with the adjacent second metal to generate coordination unsaturated and electron-deficient Au species, which facilitates the desorption of product intermediates. Consequently, the activity and selectivity of the acid-etched Au3Cu1/TiO2 are much higher than those of the untreated Au–Cu and monometallic Au catalysts. This report opens up promising possibilities for engineering highly efficient heterogeneous gold catalysts.