Plasma-Catalytic CO2-to-Energy Conversion: Fundamentals, Applications, Challenges, and Perspectives

Efficient utilization of carbon dioxide (CO2) is a critical route toward carbon cycling and low-carbon energy systems. Compared with conventional thermocatalysis, photocatalysis, and electrocatalysis, plasma catalysis can activate CO2 under relatively mild conditions through high-energy electrons, vibrationally excited molecules, radicals, and other reactive species, while catalytic surfaces can redirect reaction pathways and improve selectivity. Rather than only compiling reported performances, this review critically evaluates plasma-catalytic CO2-to-energy conversion from three perspectives: reliable mechanistic knowledge, unresolved uncertainties in plasma–catalyst synergy, and the practical credibility of reactor–catalyst combinations. The fundamentals of non-thermal plasma, CO2 activation, key metrics, plasma–catalyst coupling, and catalyst/reactor/operation factors are first clarified. Representative advances in CO2 splitting, CO2 hydrogenation, dry reforming, and CO2–H2O co-conversion are then compared with attention to energy input, selectivity, power determination, and data comparability. Finally, the key barriers to industrial deployment are discussed, including low energy efficiency, long-term catalyst stability under plasma exposure, uncertain absorbed-power measurement, incomplete carbon/oxygen balances, scale-up of filamentary discharges, and the lack of standardized reporting protocols. This review aims to provide a critical reference for mechanism-guided catalyst design, reactor engineering, and realistic process assessment in plasma-catalytic CO2 utilization.