Foam metal-enhanced dielectric barrier discharge plasma-catalytic CO₂ conversion: performance and mechanism analysis

The synergistic mechanism of dielectric barrier discharge (DBD) plasma technology combined with polymetallic composite foam catalysts X/Ni (X = Zn, Al, Cr, Mo) for CO₂ conversion was systematically investigated. Experiments were conducted to analyze the effects of foam metal packing on DBD discharge characteristics, CO₂ conversion and energy efficiency under varying packing fractions and discharge powers. It was found that foam metal packing significantly altered the DBD discharge mode, changing it from filamentary to stable surface discharge and increasing the gap capacitance. As the packing fraction increased, the energy efficiency increased to a maximum of 3.58% and CO₂ conversion significantly improved to a maximum of 27.55%. The influence of foam metal packing on CO selectivity and yield, as well as on the CO/O₂ ratio in the product gas, was studied. Mechanistic analysis revealed that the catalytic performance is intrinsically governed by the thermal stability of the surface metal coating under micro-discharge bombardment and its ability to prevent the exposure of the underlying Ni substrate. Furthermore, the superior performance of the Mo/Ni catalyst can be attributed to its robust physical barrier effect and abundant oxygen vacancies, which lower the CO₂ dissociation activation energy. This work presents a novel approach to utilizing low-temperature plasma technology in conjunction with catalysts for CO₂ conversion.