Challenges and opportunities of process intensification for the conversion of waste CO[formula omitted] to liquid fuels

Abstract

Electrochemical conversion of waste CO2 has emerged as a solution to integrate carbon capture with the production of high-value chemicals or synthetic fuels, reducing the dependence on fossil fuels while tackling the issue of intermittent availability of electricity from renewables. The main limitations of CO2 conversion are that its electro-reduction to C2+ products is difficult to control and characterized by low selectivies. On the contrary, processes for CO electro-reduction to C2+ products, characterized by high selectivities and reaction rates, have been demonstrated. The interesting opportunity is therefore emerging of developing multi-step processes in which CO2 is converted to value-added C2+ products using CO as intermediate. If the CO2 and subsequent CO electro-reduction processes could be carried out in the same location, issues related to transport and storage of CO could be overcome. In addition, the process could allow flexible production of both CO and C2+ products, depending on consumer demand. This Perspective presents an overview of CO2 capture and its subsequent two-step electro-reduction to C2+ products, with a focus on electrochemical methods and process integration, to increase the environmental and economic benefits of CO2 utilization. Integrating waste CO2 management and energy conversion, while reducing the problem of transport and storage of energy or dangerous compounds is a prime example of process intensification applied to CO2 emissions reduction.