Electrical engineering

Nanotechnology

Electrode

Organic chemistry

Electrochemical reduction of carbon dioxide

Electrocatalyst

Composite number

Engineering

Catalysis

Carbon fibers

Physical chemistry

Composite material

Biochemical engineering

Chemistry

Renewable energy

Materials science

Mass transport

Carbon monoxide

Electrochemistry

Nature Energy

The electrocatalytic reduction of carbon dioxide is a promising approach for storing (excess) renewable electricity as chemical energy in fuels. Here, we review recent advances and challenges in the understanding of electrochemical CO2 reduction. We discuss existing models for the initial activation of CO2 on the electrocatalyst and their importance for understanding selectivity. Carbon–carbon bond formation is also a key mechanistic step in CO2 electroreduction to high-density and high-value fuels. We show that both the initial CO2 activation and C–C bond formation are influenced by an intricate interplay between surface structure (both on the nano- and on the mesoscale), electrolyte effects (pH, buffer strength, ion effects) and mass transport conditions. This complex interplay is currently still far from being completely understood. In addition, we discuss recent progress in in situ spectroscopic techniques and computational techniques for mechanistic work. Finally, we identify some challenges in furthering our understanding of these themes. Electrocatalytic reduction of CO2 to fuels could be used as an approach to store renewable energy in the form of chemical energy. Here, Birdja et al. review current understanding of electrocatalytic systems and reaction pathways for these conversions.

Advances and challenges in understanding the electrocatalytic conversion of carbon dioxide to fuels