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

We report a designed Cu/C/SiO2 composite catalyst, which shows a high acetaldehyde selectivity (up to similar to 98%) and good stability for a 60 h test at 260 degrees 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 Cu-0. This reduces the concentration of active sites for secondary reactions of CH3CHO, which leads to a high initial selectivity (similar to 93%) as compared to that of Cu/SiO2 (similar to 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.