Plasma-catalytic synthesis of ammonia over Ru-based catalysts: Insights into the support effect

In this work, we have investigated the effect of different supports (activated carbon (AC), alpha-Al2O3, ZSM-5 and SiO2) on the plasma-catalytic synthesis of ammonia (NH3) from N2 and H2 over Ru-based catalysts in a dielectric barrier discharge (DBD) plasma reactor. Compared with the NH3 synthesis using plasma alone, the presence of the Ru-based catalysts in the DBD reactor significantly enhanced the NH3 production and energy yield by 163%- 387.6% with a sequence of Ru/AC > Ru/ZSM-5 > Ru/alpha-Al2O3 > Ru/SiO2. The effect of different operating parameters on the plasma-catalytic NH3 synthesis over Ru/AC was also examined. N2 adsorption-desorption experiment, X-ray diffraction analysis and temperature-programmed desorption of CO2 were performed to get insights into the structure-performance relationships between the plasma-catalytic NH3 synthesis and Ru-based catalysts with different supports. Both textural properties and the basicity of the Ru/AC catalyst contributed to the enhanced NH3 production in the hybrid plasma-catalytic system.