Revealing the Interaction between Cu and MgO in Cu/MgO Catalysts for CO Hydrogenation to CH₃OH

In this work, the structure–performance relationship of Cu/MgO catalysts was established to unravel the role of MgO and the active sites for CO hydrogenation to CH3OH synthesis, by intrinsic kinetics, chemical titration, and a series of in situ (operando) spectroscopic characterizations. The turnover rates of CH3OH formation on Cu/MgO catalysts, especially when the Mg/(Mg + Cu) atomic ratio is 0.67, were significantly higher than that on monometallic Cu particles. We have demonstrated that the rates were insensitive to the particle size of Cu but depended linearly on the quantity of Cu–MgO interfacial sites. The interaction between Cu and MgO particles improved the dispersion of Cu particles and formed more highly active Cu–MgO interfacial sites as identified by precise characterization. Moreover, this study has also unraveled that both the HCO* and HCOO* species are predominantly reactive intermediates, and their sequential hydrogenation occurs concurrently for CH3OH formation over Cu/MgO catalysts during the CO–H2 reaction

Direct Production of Lower Olefins from CO₂ Conversion via Bifunctional Catalysis

Direct conversion of carbon dioxide (CO₂) into lower olefins (C₂⁼–C₄⁼), generally referring to ethylene, propylene, and butylene, is highly attractive as a sustainable production route for its great significance in greenhouse gas control and fossil fuel substitution, but such a route always tends to be low in selectivity toward olefins. Here we present a bifunctional catalysis process that offers C₂⁼–C₄⁼ selectivity as high as 80% and C₂–C₄ selectivity around 93% at more than 35% CO₂ conversion. This is achieved by a bifunctional catalyst composed of indium–zirconium composite oxide and SAPO-34 zeolite, which is responsible for CO₂ activation and selective C–C coupling, respectively. We demonstrate that both the precise control of oxygen vacancies on the oxide surface and the integration manner of the components are crucial in the direct production of lower olefins from CO₂ hydrogenation. No obvious deactivation is observed over 150 h, indicating a promising potential for industrial application