Combining Atomic Layer Deposition with Surface Organometallic Chemistry to Enhance Atomic-Scale Interactions and Improve the Activity and Selectivity of Cu–Zn/SiO(2) Catalysts for the Hydrogenation of CO(2) to Methanol

[Image: see text] The direct synthesis of methanol via the hydrogenation of CO(2), if performed efficiently and selectively, is potentially a powerful technology for CO(2) mitigation. Here, we develop an active and selective Cu–Zn/SiO(2) catalyst for the hydrogenation of CO(2) by introducing copper and zinc onto dehydroxylated silica via surface organometallic chemistry and atomic layer deposition, respectively. At 230 °C and 25 bar, the optimized catalyst shows an intrinsic methanol formation rate of 4.3 g h(–1) g(Cu)(–1) and selectivity to methanol of 83%, with a space-time yield of 0.073 g h(–1) g(cat)(–1) at a contact time of 0.06 s g mL(–1). X-ray absorption spectroscopy at the Cu and Zn K-edges and X-ray photoelectron spectroscopy studies reveal that the CuZn alloy displays reactive metal support interactions; that is, it is stable under H(2) atmosphere and unstable under conditions of CO(2) hydrogenation, indicating that the dealloyed structure contains the sites promoting methanol synthesis. While solid-state nuclear magnetic resonance studies identify methoxy species as the main stable surface adsorbate, transient operando diffuse reflectance infrared Fourier transform spectroscopy indicates that μ-HCOO*(ZnO(x)) species that form on the Cu–Zn/SiO(2) catalyst are hydrogenated to methanol faster than the μ-HCOO*(Cu) species that are found in the Zn-free Cu/SiO(2) catalyst, supporting the role of Zn in providing a higher activity in the Cu–Zn system.