Plasma-catalytic reforming of biogas over supported Ni catalysts in a dielectric barrier discharge reactor: Effect of catalyst supports

In this study, plasma-catalytic reforming of simulated biogas for the production of value-added fuels and chemicals (e.g., H 2 ) has been carried out in a coaxial dielectric barrier discharge (DBD) plasma reactor. The influence of four Ni catalysts (Ni/γ-Al 2 O 3 , Ni/MgO, Ni/SiO 2 , and Ni/TiO 2 ) on the plasma-catalytic biogas reforming has been investigated in terms of the conversion of reactants, the yield and selectivity of target products, the carbon deposition on the catalysts, and the energy efficiency of the plasma-catalytic process. The use of plasma combined with these Ni catalysts enhanced the performance of the biogas reforming. A maximum CO 2 conversion of 26.2% and CH 4 conversion of 44.1% were achieved when using the Ni/γ-Al 2 O 3 catalyst at a specific energy density (SED) of 72 kJ l −1 . Compared to other Ni catalysts, placing the Ni/γ-Al 2 O 3 catalyst in the DBD produced more syngas and C 3  C 4 hydrocarbons, but less C 2 H 6 . The lowest energy cost (EC) for biogas conversion and syngas production, as well as the highest energy efficiency and fuel production efficiency (FPE), were achieved when using the Ni/γ-Al 2 O 3 catalyst in the plasma process. The Ni/γ-Al 2 O 3 catalyst also showed the lowest surface carbon deposition of 3.8%, after catalysing the plasma biogas reforming process for 150 min at a SED of 60 kJ l −1 . Compared to other Ni catalysts, the enhanced performance of the Ni/γ-Al 2 O 3 catalyst can be attributed to its higher specific surface area, higher reducibility and more, stronger basic sites on the catalyst surface.