Cu supported on thin carbon layer-coated porous SiO2 for efficient ethanol dehydrogenation

Abstract

We report a designed Cu/C/SiO₂ composite catalyst, which shows a high acetaldehyde selectivity (up to ∼98%) and good stability for a 60 h test at 260 °C in ethanol dehydrogenation. Various characterization techniques demonstrate that the carbon covers the Si–OH groups on silica and promotes the reduction of Cu⁺ to Cu⁰. This reduces the concentration of active sites for secondary reactions of CH₃CHO, which leads to a high initial selectivity (∼93%) as compared to that of Cu/SiO₂ (∼76%). Moreover, the chemical interaction between Cu and SiO₂ of the C/SiO₂ support, verified by X-ray photoelectron spectroscopy, enhances the interaction between the metal and the support and thus contributes to prevention of the agglomeration of Cu particles, which is the reason for the good catalytic stability of Cu/C/SiO₂. Thus, this study is an example of how careful design of the catalyst can strongly improve the catalytic performance.