Conversion of CO2 to value added chemicals: Opportunities and challenges

Abstract

The world is likely to emit almost 40 Gt/year of CO2 into the atmosphere. Even if only a small fraction of the globally emitted CO2 is captured, there will be a large quantity of CO2 available to society for use in a variety of ways. Thus, CO2 should not be regarded as a waste product, but as an asset that, with human ingenuity, could be used in a sustainable way. Since sustainability is at the intersection of environmental, economic, and intergenerational stewardship, the selection of a CO2 utilization process must offer net CO2 and waste reductions compared to conventional methods of producing the same end product, must be economical, and must not leave any additional problems for future society to solve. The criteria for selection may involve a variety of local considerations, such as government incentives, the availability of suitable renewable energy source, availability of water and other chemicals, land use, local demand for a specific product, etc. Therefore, CO2 utilization is a locally sustainable solution, rather than a one-size-fits-all approach. Utilization of CO2 may involve mostly physical processes, such as in enhanced oil recovery (EOR), solvent use, and beverage industry, where the CO2 is essentially retained in its original valence state, or chemical processes, where its valence state undergoes a change (Fig. 1). We will focus in this chapter on chemical conversion, which broadly includes thermochemical and electrochemical processes. The critical technology development parameters as well as the barriers for adoption of utilization technologies are also discussed.