Flexible NiRu Systems for CO2 Methanation: From Efficient Catalysts to Advanced Dual-Function Materials

CO2 emissions in the atmosphere have been increasing rapidly in recent years, causing global warming. CO2 methanation reaction is deemed to be a way to combat these emissions by converting CO2 into synthetic natural gas, i.e., CH4. NiRu/CeAl and NiRu/CeZr both demonstrated favourable activity for CO2 methanation, with NiRu/CeAl approaching equilibrium conversion at 350 degrees C with 100% CH4 selectivity. Its stability under high space velocity (400 L center dot g(-1)center dot h(-1)) was also commendable. By adding an adsorbent, potassium, the CO2 adsorption capability of NiRu/CeAl was boosted, allowing it to function as a dual-function material (DFM) for integrated CO2 capture and utilisation, producing 0.264 mol of CH4/kg of sample from captured CO2. Furthermore, time-resolved operando DRIFTS-MS measurements were performed to gain insights into the process mechanism. The obtained results demonstrate that CO2 was captured on basic sites and was also dissociated on metallic sites in such a way that during the reduction step, methane was produced by two different pathways. This study reveals that by adding an adsorbent to the formulation of an effective NiRu methanation catalyst, advanced dual-function materials can be designed.

Automated summary

In recent years, CO2 emissions in the atmosphere have been increasing rapidly, leading to global warming. CO2 methanation reaction is seen as a solution for this problem by converting CO2 into synthetic natural gas, or CH4. NiRu/CeAl and NiRu/CeZr have demonstrated promising activity for CO2 methanation, with NiRu/CeAl achieving near-equilibrium conversion at 350 degrees C with 100% CH4 selectivity. By adding potassium as an adsorbent, the CO2 adsorption capability of NiRu/CeAl was enhanced, allowing it to function as a dual-function material for CO2 capture and utilization, producing 0.264 mol of CH4/kg of sample from captured CO2. Time-resolved operando DRIFTS-MS measurements provided insights into the process mechanism, showing that CO2 was captured on basic sites and dissociated on metallic sites, resulting in the production of methane through two different pathways. This study highlights the potential of designing advanced dual-function materials by adding an adsorbent to an effective NiRu methanation catalyst.