CO ₂ electrolysis to multicarbon products in strong acid

Abstract

Carbon dioxide electroreduction (CO2R) is being actively studied as a promising route to convert carbon emissions to valuable chemicals and fuels. However, the fraction of input CO2 that is productively reduced has typically been very low, <2% for multicarbon products; the balance reacts with hydroxide to form carbonate in both alkaline and neutral reactors. Acidic electrolytes would overcome this limitation, but hydrogen evolution has hitherto dominated under those conditions. We report that concentrating potassium cations in the vicinity of electrochemically active sites accelerates CO2 activation to enable efficient CO2R in acid. We achieve CO2R on copper at pH <1 with a single-pass CO2 utilization of 77%, including a conversion efficiency of 50% toward multicarbon products (ethylene, ethanol, and 1-propanol) at a current density of 1.2 amperes per square centimeter and a full-cell voltage of 4.2 volts.

Cation-Driven Increases of CO2 Utilization in a Bipolar Membrane Electrode Assembly for CO2 Electrolysis

“…For example, recently, Huang et al reported ECO2R on Cu in an acid environment, which increased single-pass CO 2 utilization to 77% in a GDE flow cell. 14 Here, the protons required for CO 2 electrolysis are still envisioned to come from water-splitting, resulting in OH – formation similar to neutral and alkaline electrolytes. However, the excess protons in the surrounding electrolyte both neutralize excess OH – and reclaim CO 2 that was lost to (bi)carbonate.…”

“… 34 The improved selectivity has been explained by the better kinetics of ECO2R than HER in such environment, where the proton donor in both cases is from water and cations play less of a role in selectivity as compared to acidic media. 14 , 35 …”

Quasi-square-shaped cadmium hydroxide nanocatalysts for electrochemical CO2 reduction with high efficiency

“…In addition, the alkaline electrolyte was used, which can result in the CO 2 loss, imposing a limit of carbon utilization efficiency. 37 According to the previous reports, 38 the low concentrations of CO 2 can be directly converted to CO, however, the concentration of the CO was very low. Recently, high content of CO has been obtained via the electroreduction of the captured solution of CO 2 .…”

Technologies and perspectives for achieving carbon neutrality

“… 13 , 311 , 312 Since the pioneering works by Hori et al., 313 , 314 massive efforts have been devoted to boost the catalytic performance of electrochemical CO 2 RR, especially within the past decade. 315 , 316 , 317 , 318 , 319 , 320 , 321 There has been increasing mechanistic understanding as well as many encouraging signs of experimental progress on this complicated multi-electron and multi-proton transfer reaction system. 192 , 315 , 322 , 323 , 324 , 325 , 326 …”

“… 315 , 316 , 317 , 318 , 319 , 320 , 321 There has been increasing mechanistic understanding as well as many encouraging signs of experimental progress on this complicated multi-electron and multi-proton transfer reaction system. 192 , 315 , 322 , 323 , 324 , 325 , 326 …”