CO2 reforming in CH4 over Ni/γ-Al2O3 nano catalyst: Effect of cold plasma surface discharge

Abstract

Modernization, deforestation and overwhelmingly growing world population are significantly increasing the atmosphere CO2 level. The conversion of CO2 to other products has attracted much more attention, especially atmospheric pressure cold plasma for CO2 conversion to CH4. In this study the hydrogenation of CO2 to CH4 was carried out using Ni/γ-Al2O3 nanocatalyst coupled non-thermal plasma dielectric barrier discharge reactor (NTP-DBD). The effect of temperature, plasma input power on CO2 conversion rate and CH4 selectivity have been studied. It was evidenced that, compared to conventional thermal catalysis (300 °C), plasma-catalysis has shown temperature shift (T shift) of 50 °C (250 °C). Furthermore, at 250 °C, 10wt.%Ni/γ-Al2O3 nanocatalyst has shown about 40% CO2 conversion and 70% CH4 selectivity with 340 J.L−1 specific input energy (SIE). At low operating temperature, increase in SIE increases the CO2 conversion and CH4 selectivity by about 10%. The SEM and EDX analysis evidenced that NiO is homogeneously dispersed on the alumina beads surface. The TEM analysis before and after catalytic experiments showed that the average “NiO” particle size is 10–12 nm and 12–15 nm, respectively. The plasma discharge slightly increases the Ni particle size, however, it does not affect neither CO2 conversion and nor CH4 selectivity.