CO2 electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface
18 May 2018-Science (American Association for the Advancement of Science)-Vol. 360, Iss: 6390, pp 783-787
TL;DR: A copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO2 to ethylene with 70% faradaic efficiency at a potential of −0.55 volts versus a reversible hydrogen electrode (RHE).
Abstract: Carbon dioxide (CO 2 ) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO 2 to ethylene with 70% faradaic efficiency at a potential of −0.55 volts versus a reversible hydrogen electrode (RHE). Hydroxide ions on or near the copper surface lower the CO 2 reduction and carbon monoxide (CO)–CO coupling activation energy barriers; as a result, onset of ethylene evolution at −0.165 volts versus an RHE in 10 molar potassium hydroxide occurs almost simultaneously with CO production. Operational stability was enhanced via the introduction of a polymer-based gas diffusion layer that sandwiches the reaction interface between separate hydrophobic and conductive supports, providing constant ethylene selectivity for an initial 150 operating hours.
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TL;DR: In this article, an overview of the limitations of CO2 reduction in terms of devices, processes, and catalysts is provided, and the economic feasibility of the CO2 conversion technology is described in individual processes such as reactions and separation.
Abstract: The severe increase in the CO2 concentration is a causative factor of global warming, which accelerates the destruction of ecosystems. The massive utilization of CO2 for value-added chemical production is a key to commercialization to guarantee both economic feasibility and negative carbon emission. Although the electrochemical reduction of CO2 is one of the most promising technologies, there are remaining challenges for large-scale production. Herein, an overview of these limitations is provided in terms of devices, processes, and catalysts. Further, the economic feasibility of the technology is described in terms of individual processes such as reactions and separation. Additionally, for the practical implementation of the electrochemical CO2 conversion technology, stable electrocatalytic performances need to be addressed in terms of current density, Faradaic efficiency, and overpotential. Hence, the present review also covers the known degradation behaviors and mechanisms of electrocatalysts and electrodes during electrolysis. Furthermore, strategic approaches for overcoming the stability issues are introduced based on recent reports from various research areas involved in the electrocatalytic conversion.
33 citations
TL;DR: In this article, a review of recent advances in how to design efficient single-atom electrocatalysts for multi-electron reduction of CO2, with emphasis on strategies in regulating the interactions between active sites and key reaction intermediates, is summarized.
Abstract: The multi-electron reduction of CO2 to hydrocarbons or alcohols is highly attractive in a sustainable energy economy, and the rational design of electrocatalysts is vital to achieve these reactions efficiently. Single-atom electrocatalysts are promising candidates due to their well-defined coordination configurations and unique electronic structures, which are critical for delivering high activity and selectivity and may accelerate the explorations of the activity origin at atomic level as well. Although much effort has been devoted to multi-electron reduction of CO2 on single-atom electrocatalysts, there are still no reviews focusing on this emerging field and constructive perspectives are also urgent to be addressed. Herein recent advances in how to design efficient single-atom electrocatalysts for multi-electron reduction of CO2 , with emphasis on strategies in regulating the interactions between active sites and key reaction intermediates, are summarized. Such interactions are crucial in designing active sites for optimizing the multi-electron reduction steps and maximizing the catalytic performance. Different design strategies including regulation of metal centers, single-atom alloys, non-metal single-atom catalysts, and tandem catalysts, are discussed accordingly. Finally, current challenges and future opportunities for deep electroreduction of CO2 are proposed.
32 citations
TL;DR: In this article, high-density nitrogen vacancies formed on cubic copper nitrite (Cu3 Nx ) feature as efficient electrocatalytic centers for CO-CO coupling to form the key OCCO* intermediate toward C2 products.
Abstract: Electrochemical CO2 reduction to produce valuable C2 products is attractive but still suffers with relatively poor selectivity and stability at high current densities, mainly due to the low efficiency in the coupling of two *CO intermediates. Herein, it is demonstrated that high-density nitrogen vacancies formed on cubic copper nitrite (Cu3 Nx ) feature as efficient electrocatalytic centers for CO-CO coupling to form the key OCCO* intermediate toward C2 products. Cu3 Nx with different nitrogen densities are fabricated by an electrochemical lithium tuning strategy, and density functional theory calculations indicate that the adsorption energies of CO* and the energy barriers of forming key C2 intermediates are strongly correlated with nitrogen vacancy density. The Cu3 Nx catalyst with abundant nitrogen vacancies presents one of the highest Faradaic efficiencies toward C2 products of 81.7 ± 2.3% at -1.15 V versus reversible hydrogen electrode (without ohmic correction), corresponding to the partial current density for C2 production as -307 ± 9 mA cm-2 . An outstanding electrochemical stability is also demonstrated at high current densities, substantially exceeding CuOx catalysts with oxygen vacancies. The work suggests an attractive approach to create stable anion vacancies as catalytic centers toward multicarbon products in electrochemical CO2 reduction.
32 citations
DOI•
01 Nov 2021TL;DR: In this article, the authors highlight the areas in which coordinated efforts can support commercialization of such capture and catalytic technologies while deploying the required infrastructure, from R&D to policy.
Abstract: Electrocatalytic conversion of CO2 into useful products can contribute to the Paris goals on the basis of abundant low-carbon power and technological advances. From R&D to policy, areas are highlighted in which coordinated efforts can support commercialization of such capture and catalytic technologies while deploying the required infrastructure.
32 citations
TL;DR: In this article , a cooperative Ni single-atom on nanoparticle catalyst (NiSA/NP) via direct solid-state pyrolysis, where Ni nanoparticles donate electrons to Ni(i)-N-C sites via carbon nanotubes network, achieving a high CO current density of 346 mA cm -2 at -0.5 V vs RHE in an alkaline flow cell.
Abstract: The electronic modulation of atomic dispersed active sites is promising to boost the catalytic activity, which is however remains a challenge. Here we show a cooperative Ni single-atom on nanoparticle catalyst (NiSA/NP) via direct solid-state pyrolysis, where Ni nanoparticles donate electrons to Ni(i)-N-C sites via carbon nanotubes network, achieving a high CO current density of 346 mA cm -2 at -0.5 V vs RHE in an alkaline flow cell. When coupled with a NiFe-based oxygen evolution anode into a zero-gap membrane electrolyzer, it delivers an industrial-relevant CO current density of 310 mA cm -2 at a low cell voltage of -2.3 V, corresponding to an overall energy efficiency of 57%. The superior CO 2 electroreduction performance is attributed to the enhanced adsorption of key intermediate COOH* on electron-rich Ni single atom, together with the dense active sites.
32 citations
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TL;DR: An improved way of estimating the local tangent in the nudged elastic band method for finding minimum energy paths is presented, and examples given where a complementary method, the dimer method, is used to efficiently converge to the saddle point.
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