Performance and mechanism of CO2 reduction by DBD-coupled mesoporous SiO2

Abstract In the process of CO2 reduction with dielectric barrier discharge (DBD)-coupled catalysis, the existing material presents unsatisfactory synergy, such as high cost, complicated preparation processes, and low conversion rates. An inexpensive and environmentally friendly mesoporous SiO2 with different morphologies by gel–sol method was synthesized and then introduced for synergistic conversion of CO2 with DBD. The physicochemical properties of the synthesized mesoporous SiO2 materials were analyzed using X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and Brunauer-Emmett-Teller method, indicated the prepared mesoporous materials manifested large specific surface areas, ordered pore channels and pore size, and good stability. The CO2 reduction performance, CO selectivity, and energy efficiency of DBD alone and DBD-coupled mesoporous SiO2 were investigated at different input powers. The SiO2 prepared with 1.05 g cetyltrimethylammonium bromide addition had the highest activity, in which the conversion of CO2, CO yield and energy efficiency were increased by 56.73, 68.41, and 122.31%, respectively, compared with DBD alone. The primary CO2 conversion mechanism of the mesoporous SiO2-coupled DBD was analyzed. It is shown that the suitable pore capacity structure, the large specific surface area, and the presence of filament discharge within the pore size of suitable mesoporous material can promote the decomposition of CO2 on its surface.