Influence of Microwave Irradiation on the Structural Properties of Carbon-Supported Hollow Copper Nanoparticles and Their Effect on the Synthesis of Dimethyl Carbonate

摘要

Novel activated carbon (AC)-supported highly dispersed hollow Cu nanoparticles (NPs) (Cu/AC) with exposed {111} facets have been prepared by microwave irradiation for the synthesis of dimethyl carbonate (DMC). In particular, Cu NPs with a large cavity diameter of 35nm are formed after irradiation from room temperature to 360 degrees C within a mere 8min without additional irradiation, thus benefiting from the rapid heating of the microwave procedure. In this study, an Ostwald ripening mechanism is proposed. DFT calculations are consistent with the analysis of CO temperature-programmed desorption, which found that Cu(111) facets are more favorable for the weak adsorption of CO, which supports the formation of DMC. The as-prepared catalysts exhibit the highest DMC formation rate in terms of turnover frequency and 100% selectivity for DMC can be achieved. The large surface area of the hollow Cu NPs and the exposed {111} crystal planes are highlighted as being responsible for the excellent catalytic rate and superior selectivity, respectively.