Evaluating the Potential of Thermal Catalysis for Environmental Methane Mitigation

Methane (CH4), is a potent greenhouse gas released from a wide range of natural and anthropogenic sources. This study explores the performance of thermal catalysis for CH4 abatement under dilute conditions (10–500 ppm), representative of real-world environments. A matrix of catalysts comprising of 1 wt% Pd, Ni, and Ag metals supported on CeO2, TiO2, and Al2O3 was synthesized and screened for CH4 oxidation activity. Pd/CeO2 exhibited the highest activity across all concentrations, achieving complete conversion (>95%) below 500°C at 500 ppm down to 10 ppm of CH4. However, Ag- and Ni-based catalysts, particularly when supported on Al2O3, demonstrated promising activity at higher temperatures, over 80% conversion at 800°C for all CH4 concentrations examined, offering potential cheaper alternatives to Pd. A life-cycle climate-impact assessment further contextualised the catalysts potential for CH4 abatement, accounting for CO2 production, CH4 removal, heating and material emissions. While Pd catalysts showed the highest CH4 conversion, some Ag and Ni catalysts delivered similar net CO2e emission rates when life- cycle costs were included. The results highlight the balance between catalyst cost, activity, and net climate benefit, emphasizing the importance of material selection for scalable, low-concentration CH4 mitigation.