A review on high-pressure heterogeneous catalytic processes for gas-phase CO₂ valorization

This review discusses the importance of mitigating CO₂ emissions by valorizing CO₂ through high-pressure catalytic processes. It focuses on various key processes, including CO₂ methanation, reverse water-gas shift, methane dry reforming, methanol, and dimethyl ether synthesis, emphasizing pros and cons of high-pressure operation. CO₂ methanation, methanol synthesis, and dimethyl ether synthesis reactions are thermodynamically favored under high-pressure conditions. However, in the case of methane dry reforming and reverse water-gas shift, applying high pressure, results in decreased selectivity toward desired products and an increase in coke production, which can be detrimental to both the catalyst and the reaction system. Nevertheless, high-pressure utilization proves industrially advantageous for cost reduction when these processes are integrated with Fischer-Tropsch or methanol synthesis units. This review also compiles recent advances in heterogeneous catalysts design for high-pressure applications. By examining the impact of pressure on CO₂ valorization and the state of the art, this work contributes to improving scientific understanding and optimizing these processes for sustainable CO₂ management, as well as addressing challenges in high-pressure CO₂ valorization that are crucial for industrial scaling-up. This includes the development of cost-effective and robust reactor materials and the development of low-cost catalysts that yield improved selectivity and long-term stability under realistic working environments.