Understanding of tri-reforming of methane over Ni/Mg/Al hydrotalcite-derived catalyst for CO2 utilization from flue gases from natural gas-fired power plants

Tri-reforming of methane was examined over Ni/Mg/Al hydrotalcite-derived catalyst for CO2 utilization directly from simulated flue gas mixtures from natural gas-fired power plants. This catalyst showed promising results for the studied experimental conditions, revealing the following order of CH4 conversion: TRM3 (75.9 %) < TRM2 (91.9 %) < TRM1 (98.2 %). The activity trend was related to the Ni crystallite size, with smaller particles leading to increased conversion. The highest TOF value was found for gas feed with elevated CH4 concentration (TRM3), possibly due to a significant contribution of side reactions parallelly occurring during tri-reforming of methane. The HTNi catalyst after TRM3 showed bigger Ni-0 particles, which are prone to participate in the formation of graphitic-like carbon. The presence of encapsulated Ni particles and carbon nanotubes was confirmed by XRD, TGA, HRTEM, and ToF-SIMS for HTNi used in TRM3.