Promoting Electrolysis of Carbon Monoxide toward Acetate and 1-Propanol in Flow Electrolyzer

Abstract

Acetic acid/acetate is an important precursor for many chemical manufacturing sectors, as well as a feedstock for the microbial synthesis of value-added biofuel and biomass products. As the downstream reaction in tandem with the carbon dioxide reduction reaction, carbon monoxide electrolysis has a unique advantage over direct carbon dioxide reduction, boosting the selectivity for multicarbon products. However, highly selective and high-current-throughput acetate and 1propanol production from CO electrolysis is yet to be explored. Herein, we present practical approaches for improving acetate and 1-propanol selectivity and yield from CO electrolysis using a commercial copper catalyst. Acetate showed a strong pH dependence with an optimum performance at 90% Faradaic efficiency and 128 mA cm −2 current density. In addition, 1-propanol showed a strong catalyst loading dependence, achieving 20% Faradaic efficiency under high-catalyst-loading conditions. In situ Raman and Multiphysics modeling further demonstrated the mechanism of the improvements.

Directing the Selectivity of CO Electrolysis to Acetate by Constructing Metal‐Organic Interfaces

“…The maximum full‐cell energy efficiencies (EEs) for acetate and C 2+ production are 27.3 % and 33.5 %, respectively (Figures 1c and S4). The presented performance for CO electrolysis to acetate outperforms all previously reported results, in terms of FE and partial current density (Figure 1d and Table S1), [6d–v] as well as those for selective production of other specific C 2+ products like ethylene, ethanol, and propane [6a–c] . The stability test of the CuPc catalyst was further conducted at an applied current density of 300 mA cm −2 under 0.5 MPa CO feed (Figures 1e and S5).…”

Directing the Selectivity of CO Electrolysis to Acetate by Constructing Metal‐Organic Interfaces

“…The maximum full‐cell energy efficiencies (EEs) for acetate and C 2+ production are 27.3 % and 33.5 %, respectively (Figures 1c and S4). The presented performance for CO electrolysis to acetate outperforms all previously reported results, in terms of FE and partial current density (Figure 1d and Table S1), [6d–v] as well as those for selective production of other specific C 2+ products like ethylene, ethanol, and propane [6a–c] . The stability test of the CuPc catalyst was further conducted at an applied current density of 300 mA cm −2 under 0.5 MPa CO feed (Figures 1e and S5).…”

An Organic “Proton Cage” that is Ultra-Resistant to Hydroxide-Promoted Degradation

“…16,25,26 To overcome this key challenge, it is thus imperative to improve the durability of organic cations in highly caustic environments. 18,[21][22][23][24][25] Development of more durable AEMs has already bene ted signi cantly from increasing the alkaline stability of cation-hydroxides. Our group, for example, developed steric protection strategies to substantially enhance the stability of (benz)imidazolium cations, 25,[27][28][29] while other research groups have enhanced the durability of ammonium cations by steric protection with cyclohexane 'chair' con gurations, 16,24,30 and by limiting degradative de-alkylation by controlling alkyl-chain lengths.…”

“…1a). 22,24,25 Although highly stable under caustic conditions when fully hydrated, none are considered stable over extended periods under low RH/elevated temperature applications. 1,4,37 In addition to high stability, cations should possess a low molecular weight, to enable the formation of polymers with high ion exchange capacity (IEC) and thus high hydroxide conductivity.…”