Plasma‐enhanced NH3 synthesis over activated carbon‐based catalysts: Effect of active metal phase

In this study, plasma‐enhanced NH3 synthesis over a series of M/AC (M = Ru, Co, Ni, and Fe) catalysts was investigated. The combination of the plasma and activated carbon (AC) enhanced the reaction performance compared with the reaction using plasma alone. The doping of active metal on AC further improved the reaction performance by up to 37.3%. The highest NH3 concentration of 3,026.5 ppm was obtained over Ru/AC at a specific input energy (SIE) of 12.5 kJ/L, followed by Co/AC, Fe/AC, and Ni/AC. The highest energy efficiency of 0.72 g/kWh was achieved at an SIE of 8.0 kJ/L when using the Ru/AC catalyst. Catalyst characterizations showed that the basicity of the M/AC catalysts plays an important role in the plasma‐enhanced catalytic synthesis of NH3. The reaction mechanism in the plasma‐enhanced NH3 synthesis was also discussed.