Directing the Outcome of CO<sub>2</sub> Reduction at Bismuth Cathodes Using Varied Ionic Liquid Promoters

Atifi, Abderrahman; Boyce, David W.; DiMeglio, John L.; Rosenthal, Joel

doi:10.1021/acscatal.7b03433

Cited by 109 publications

(92 citation statements)

References 62 publications

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“…By employing Cs + -based electrolytes, the authors enhance CO 2 reduction kinetics while promoting C-C bond-forming electroreduction processes. These efforts are in line with previous studies demonstrating how the size and electronic properties of electrolyte additives can impact the selectivity and kinetics of CO 2 RR processes (14,15). Moreover, by tailoring the electrolyte concentration and pH of the catholyte (pH 6.8) and anolyte (pH 11), Huan et al could achieve rapid reduction of CO 2 to hydrocarbons.…”

Section: Co Co 2 Rr To C Rr To C 1 Products Products Co Co 2 Rr To C supporting

confidence: 80%

Solar-powered synthesis of hydrocarbons from carbon dioxide and water

Kunene

Xiong

Rosenthal

2019

Proc. Natl. Acad. Sci. U.S.A.

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The synthesis of hydrocarbons via electroreduction of CO 2 is an attractive approach to store energy generated from intermittent renewable sources of electricity (e.g., solar) through formation of the high-energy C-C and C-H bonds of reduced carbon compounds (1, 2). Establishment of such processes also represents a critical step toward the sustainable production of carbonbased commodity chemicals and energy-rich liquid fuels from nonpetroleum resources (3). Despite the promise that such strategies hold, facilitating the rapid, selective, and efficient electrosynthesis of multicarbon products from CO 2 is an inherently difficult proposition. Part of the challenge stems from the fact that CO 2 reduction half-reactions that generate value-added C 1 and multicarbon products take place within a narrow potential window that is less than 0.5 V wide ( Fig. 1).As a result of the reaction landscape illustrated in Fig. 1, it is virtually impossible to target a given CO 2 reduction product based purely on thermodynamic considerations. For instance, electrochemical reduction of CO 2 to ethylene occurs at 0.08 V vs. reversible hydrogen electrode (RHE). Accordingly, any electrochemical process that targets this product must be run at a potential at which production of other species such as ethane (E°= 0.14 V) and methane (E°= 0.17 V) is also thermodynamically feasible. Moreover, kinetics associated with CO 2 reduction reactions (CO 2 RRs) can often be sluggish. This is particularly true for CO 2 RR processes that generate reduced products with C-C bonds, which require application of modest overpotentials of at least 400 to 500 mV. In practice, electrochemical hydrocarbon evolution ultimately requires cathodic potentials that are more negative than -0.5 V vs. RHE, which ultimately brings all of the CO 2 couples of Fig. 1 into play. Matters are further complicated by the fact that each CO 2 reduction couple requires both eand H + equivalents. As a result, the kinetically facile reduction of protons to hydrogen gas (E°= 0.0 V) represents a competitive cathodic process that must be suppressed for efficient and selective hydrocarbon evolution to be realized.Each CO 2 reduction half-reaction requires multiple eand H + equivalents that are most logically provided by the oxidation of water (E°= 1.23 V). Accordingly, electrochemical cells (ECs) for sustainable hydrocarbon synthesis must juxtapose cathode and anode catalysts that can manage the demanding multielectron proton-coupled electron transfer reactions attendant to CO 2 reduction and H 2 O oxidation, respectively. Moreover, since production of hydrocarbons from Potential versus RHE (V) Fig. 1. Equilibrium potentials for reductive and oxidative half-reactions relevant to the synthesis of hydrocarbons from carbon dioxide, water, and sunlight. Electron and proton equivalents generated via water oxidation at the anode of an EC can be utilized for fuel-forming cathodic processes to generate hydrogen gas or a broad array of reduced carbon products. Promoting the efficient and selective...

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Section: Co Co 2 Rr To C Rr To C 1 Products Products Co Co 2 Rr To C supporting

confidence: 80%

Solar-powered synthesis of hydrocarbons from carbon dioxide and water

Kunene

Xiong

Rosenthal

2019

Proc. Natl. Acad. Sci. U.S.A.

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“…Recent research efforts have focused on finding non‐noble earth‐abundant catalysts for formate production. Tin, bismuth, and lead have shown high stability and selectivity . Despite the vast choice of catalysts, their productivity has generally not been sufficiently high .…”

Section: Performance Comparison Of Various Non‐noble Metals For Co2 Ementioning

confidence: 99%

2D Metal Oxyhalide‐Derived Catalysts for Efficient CO₂ Electroreduction

et al. 2018

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Electrochemical reduction of CO is a compelling route to store renewable electricity in the form of carbon-based fuels. Efficient electrochemical reduction of CO requires catalysts that combine high activity, high selectivity, and low overpotential. Extensive surface reconstruction of metal catalysts under high productivity operating conditions (high current densities, reducing potentials, and variable pH) renders the realization of tailored catalysts that maximize the exposure of the most favorable facets, the number of active sites, and the oxidation state all the more challenging. Earth-abundant transition metals such as tin, bismuth, and lead have been proven stable and product-specific, but exhibit limited partial current densities. Here, a strategy that employs bismuth oxyhalides as a template from which 2D bismuth-based catalysts are derived is reported. The BiOBr-templated catalyst exhibits a preferential exposure of highly active Bi ( ) facets. Thereby, the CO reduction reaction selectivity is increased to over 90% Faradaic efficiency and simultaneously stable current densities of up to 200 mA cm are achieved-more than a twofold increase in the production of the energy-storage liquid formic acid compared to previous best Bi catalysts.

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“…understanding is expected to advance various design strategies, such as the decoration of the electrode surface with molecular cocatalysts (59)(60)(61)(62)(63).…”

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confidence: 99%

Hydrogen bonding steers the product selectivity of electrocatalytic CO reduction

Gunathunge

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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The product selectivity of many heterogeneous electrocatalytic processes is profoundly affected by the liquid side of the electrocatalytic interface. The electrocatalytic reduction of CO to hydrocarbons on Cu electrodes is a prototypical example of such a process. However, probing the interactions of surface-bound intermediates with their liquid reaction environment poses a formidable experimental challenge. As a result, the molecular origins of the dependence of the product selectivity on the characteristics of the electrolyte are still poorly understood. Herein, we examined the chemical and electrostatic interactions of surfaceadsorbed CO with its liquid reaction environment. Using a series of quaternary alkyl ammonium cations (methyl 4 N + , ethyl 4 N + , propyl 4 N + , and butyl 4 N + ), we systematically tuned the properties of this environment. With differential electrochemical mass spectrometry (DEMS), we show that ethylene is produced in the presence of methyl 4 N + and ethyl 4 N + cations, whereas this product is not synthesized in propyl 4 N + -and butyl 4 N + -containing electrolytes. Surface-enhanced infrared absorption spectroscopy (SEIRAS) reveals that the cations do not block CO adsorption sites and that the cation-dependent interfacial electric field is too small to account for the observed changes in selectivity. However, SEIRAS shows that an intermolecular interaction between surface-adsorbed CO and interfacial water is disrupted in the presence of the two larger cations. This observation suggests that this interaction promotes the hydrogenation of surface-bound CO to ethylene. Our study provides a critical molecular-level insight into how interactions of surface species with the liquid reaction environment control the selectivity of this complex electrocatalytic process.hydrogen bonding | cation effects | electrocatalysis | carbon dioxide reduction | catalytic selectivity T he reaction environment profoundly impacts the kinetics of many chemical processes. Examples include the influence of the solvating environment on the rates of electron transfer (1), isomerization (2), peptide folding (3), and organic reactions (4), as well as the sensitivity of enzymatic catalysis to changes in the molecular structure of the active site (5). For a chemical process that can lead to multiple reaction products, solvent effects can impact the relative rates of product formation and therefore the product selectivity (6, 7). These effects, which can have complex energetic and/or dynamical origins (1,8,9), are fundamentally rooted in intermolecular interactions between the reactants and their environment. In the context of heterogeneous electrocatalysis, the reaction environment is asymmetric; i.e., reactants at the electrochemical interface are interacting with the solid electrode and the liquid electrolyte. Understanding the interactions of intermediates with their interfacial environment is essential for controlling the reaction paths of electrocatalytic processes that exhibit poor product selectivity.The reduc...

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Directing the Outcome of CO₂ Reduction at Bismuth Cathodes Using Varied Ionic Liquid Promoters

Cited by 109 publications

References 62 publications

Solar-powered synthesis of hydrocarbons from carbon dioxide and water

Solar-powered synthesis of hydrocarbons from carbon dioxide and water

2D Metal Oxyhalide‐Derived Catalysts for Efficient CO₂ Electroreduction

Hydrogen bonding steers the product selectivity of electrocatalytic CO reduction

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Directing the Outcome of CO2 Reduction at Bismuth Cathodes Using Varied Ionic Liquid Promoters

Cited by 109 publications

References 62 publications

Solar-powered synthesis of hydrocarbons from carbon dioxide and water

Solar-powered synthesis of hydrocarbons from carbon dioxide and water

2D Metal Oxyhalide‐Derived Catalysts for Efficient CO2 Electroreduction

Hydrogen bonding steers the product selectivity of electrocatalytic CO reduction

Contact Info

Product

Resources

About

Directing the Outcome of CO₂ Reduction at Bismuth Cathodes Using Varied Ionic Liquid Promoters

2D Metal Oxyhalide‐Derived Catalysts for Efficient CO₂ Electroreduction