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

Abstract

Electrochemically converting CO2 to valuable chemicals holds great promise for closing the anthropogenic carbon cycle. Owing to complex reaction pathways and shared rate‐determining steps, directing the selectivity of CO2/CO electrolysis to a specific multi‐carbon product is very challenging. We report here a strategy for highly selective production of acetate from CO electrolysis by constructing metal‐organic interfaces. We demonstrate that the Cu‐organic interfaces constructed by in situ reconstruction of Cu complexes show very impressive acetate selectivity, with a high Faradaic efficiency of 84.2% and a carbon selectivity of 92.1% for acetate production, in an alkaline membrane electrode assembly electrolyzer. The maximum acetate partial current density and acetate yield reach as high as 605 mA cm−2 and 63.4%, respectively. Thorough structural characterizations, control experiments, operando Raman spectroscopy measurements, and density functional theory calculation results indicate that the Cu‐organic interface creates a favorable reaction microenvironment that enhances *CO adsorption, lowers the energy barrier for C−C coupling, and facilitates the formation of CH3COOH over other multicarbon products, thus rationalizing the selective acetate production.

Highly selective hydrogen peroxide electrosynthesis on copper phthalocyanine: interface engineering with an azo-polymer

“…As shown in Fig. 2d and S8a,† the binding energy at 397.9 eV is assigned to the carbazole unit and triphenylamine unit (C–N), 51 and the binding energy at 398.6 eV is assigned to Cu–N species in the CuPc unit. 52 The binding energies at 399.5 eV and 400.1 eV can be assigned to the nitrogen species in the bridge position (CN) and azo functionalities (NN), respectively.…”

Continuously Producing Highly Concentrated and Pure Acetic Acid Aqueous Solution via Direct Electroreduction of CO2

“…According to previous reports, the further reduction of the *HOCCOH intermediate during CO reduction could lead to two possible intermediates: further reduction of the *CCO intermediate yielding acetic acid or acetate products and that of the *CCOH intermediate yielding ethylene or ethanol products. 9,26,44 Obviously, for MAF-2, the energy barrier for generating the *CCO intermediate with a high CO coverage (−0.49 eV) is lower than that for generating the *CCOH intermediate (0.11 eV), which is conducive to the generation of acetate as the main product (Figure 5e). Moreover, the energy barrier for generating the *CCOH intermediate with low CO coverage is lower than that in high CO coverage, making the generation of ethylene and ethanol easier.…”

“…In this scenario, directly collecting acetic acid in a neutral environment without other solutes during an efficient eCO 2 RR process in the MEA presents a significant challenge and has not been realized so far. Instead, electrochemical CO reduction reactions (eCORR) have proven to be more effective for efficient acetate production due to the lower acidity of CO compared to CO 2 . ,− However, compared with using inexpensive CO 2 as a feedstock, the adoption of the high-purity CO gas as a reactant can substantially escalate the cost of acetate production. In light of these challenges and considerations, it is imperative to advance the development of novel electrocatalytic systems that can enhance the performance of the eCO 2 RR to yield acetic acid.…”

Molecular Enhancement of Direct Electrolysis of Dilute CO2

“…18−27 The production of CO, a two-electron reduction product, has gained great attention due to its excellent techno-economic feasibility 1,6 and good suitability as a reactant for improved C− C coupling in tandem electrolysis routes. 28,29 However, previous studies on the direct electrolysis of dilute CO 2 to CO are mostly performed at low current densities and use catalysts prepared by complicated synthesis protocols (Table S1). 7−10,24−27 There is an urgent need to develop efficient catalyst systems for high-rate direct electrolysis of dilute CO 2 streams toward practical application.…”

“…Despite these difficulties, researchers have developed a group of strategies to increase local CO 2 concentrations in reaction microenvironments around catalytically active sites by enriching CO 2 from dilute streams, namely, the integration of carbon capture and conversion into a single system. , In nature, such an enrichment effect performed by enzymes enables efficient photosynthesis of complex carbohydrates directly from atmospheric CO 2 . This bioinspired strategy has recently been applied to the rational design of molecular catalysts and heterogeneous catalysts with specific structures and functional groups for direct electrolysis of dilute CO 2 . − The production of CO, a two-electron reduction product, has gained great attention due to its excellent techno-economic feasibility , and good suitability as a reactant for improved C–C coupling in tandem electrolysis routes. , However, previous studies on the direct electrolysis of dilute CO 2 to CO are mostly performed at low current densities and use catalysts prepared by complicated synthesis protocols (Table S1). −, − There is an urgent need to develop efficient catalyst systems for high-rate direct electrolysis of dilute CO 2 streams toward practical application.…”