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In terms of the reaction of CO_2 reduction to CO with hydrogen, CO_2 conversion is very low at low temperature due to the limitation of thermodynamic equilibrium(TE). To overcome this limitation, plasma catalytic reduction of CO_2 to CO in a catalyst-filled dielectric barrier discharge(DBD) reactor is studied. An enhanced effect of plasma on the reaction over Au/CeO_2 catalysts is observed. For both the conventionally catalytic(CC) and plasma catalytic(PC, Pin= 15 W) reactions under conditions of 400 °C, H_2/CO_2= 1,200 SCCM, GHSV = 12,000 mL·g~(-1)cat·h~(-1), CO_2 conversions over Au/CeO_2 reach 15.4% and 25.5% due to the presence of Au, respectively, however, those over CeO_2 are extremely low and negligible. Moreover,CO_2 conversion over Au/CeO_2 in the PC reaction exceeds 22.4% of the TE conversion. Surface intermediate species formed on the catalyst samples during the reactions are determined by in-situ temperatureprogrammed decomposition(TPD) technique. Interestingly, it disclosed that in the PC reaction, the formation of formate intermediate is enhanced by plasma, and the acceleration by plasma in the decomposition of formate species is much greater than that in the formation of formate species on Au/CeO_2. Enhancement factor is introduced to quantify the enhanced effect of plasma. Lower reactor temperature, higher gas hourly space velocity(GHSV), and lower molar ratio of H_2/CO_2 would be associated with larger enhancement factor.
In terms of the reaction of CO_2 reduction to CO with hydrogen, CO_2 conversion is very low at low temperature due to the limitation of thermodynamic equilibrium (TE). To overcome this limitation, plasma catalytic reduction of CO_2 to CO in a catalyst-filled dielectric For both the conventionally catalytic (CC) and plasma catalytic (PC, Pin = 15 W) reactions under conditions of 400 ° C, H 2 / CO 2 = 1,200 SCCM, GHSV = 12,000 mL · g -1 cat · h -1, CO 2 conversions over Au / CeO 2 reach 15.4% and 25.5% due to the presence of Au, respectively, However, those over CeO 2 are extremely low and negligible. Furthermore, CO 2 conversion over Au / CeO 2 in the PC reaction exceeds 22.4% of the TE conversion. Surface intermediate species formed on the catalyst samples during the reactions are determined by in-situ temperature programmed decomposition (TPD) technique. Interestingly, it discl osed that in the PC reaction, the formation of formate intermediate is enhanced by plasma, and the acceleration by plasma in the decomposition of formate species is much more than that in the formation of formate species on Au / CeO 2. Enhancement factor is introduced to quantify the enhanced effect of plasma. Lower reactor temperature, higher gas hourly space velocity (GHSV), and lower molar ratio of H 2 / CO 2 would be associated with larger enhancement factor.