Redox and Nonredox CO₂Utilization: Dry Reforming of Methane and Catalytic Cyclic Carbonate Formation

CO2 emissions are too large to tackle with a single process, but a combination of avoidance with chemical utilization may be able to slow global warming. In this Focus Review, we identify two large-scale CO2 conversion processes based on their viability and opposite energy requirements. In the high-energy, stationary path, CO2 reforming of methane could provide gigatons of CO2 utilization through synthesis gas. The main problem is the lack of a durable, effective, low-cost dry reforming catalyst. The exothermic cyclic carbonate formation from CO2 and organic epoxides offers a low-energy, mobile, nonredox route. The catalysts, however, must be metal-free and robust, have a high surface area, and be low-cost while being easily scalable. These two processes could potentially address at least a quarter of all current CO2 emissions.