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, a review of catalysts for the electrochemical CO2 reduction reaction (eCO2RR) is presented, focusing on efforts to improve electrochemical stability of the catalysts.
Abstract: The gradual increase in the atmospheric CO2 concentration is an urgent issue that poses a threat to human beings. Recently, the electrochemical CO2 reduction reaction (eCO2RR) has arisen as a promising and eco-friendly strategy for the storage of electricity from renewable sources as permanent chemical energy, as well as for the conversion of atmospheric CO2 into value-added chemicals. Among various catalysts, transition metals have been employed as heterogeneous electrocatalysts to yield valuable carbon chemicals such as carbon monoxide, formic acid, ethylene, and ethanol. Recent developments in catalysts and electrochemical devices have boosted catalytic activities and product selectivities, bringing the eCO2RR to practically promising levels. However, a lack of study to secure stable catalysts for eCO2RR remains a major obstacle for further progress of this technology. This review focuses on efforts to improve the electrochemical stability of catalysts. First, the catalyst deactivation process, including contaminations by metal impurities or carbon derivatives and changes in catalyst morphology during the eCO2RR, is discussed to understand the origin of insufficient stability. Next, recent progress in strategies for the preparation of highly stable catalyst systems will be presented. The discussion of valuable approaches that effectively prevent deactivation processes, such as the exclusion of metal impurities, periodic electrochemical activation, and the design of stable catalysts through the manipulation of various factors, allows identification of several clues for long-term stability. We hope that this review will inspire future catalyst design and stimulate the development of new ideas for the improvement of electrochemical stability.
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TL;DR: In this article , the concept of carbon energy index and the recent progress in petroleum refining, and the production of liquid fuels, chemicals, and materials using coal, methane, CO2 , biomass, and waste plastics is highlighted in combination with green carbon science.
Abstract: Green carbon science is defined as the "study and optimization of the transformation of carbon-containing compounds and the relevant processes involved in the entire carbon cycle from carbon resource processing, carbon energy utilization, CO2 fixation, and carbon recycling to utilize carbon resources efficiently and minimize the net CO2 emission."[1] Green carbon science is related closely to carbon neutrality, and relevant fields have developed quickly in the last decade. In this Minireview, we propose the concept of carbon energy index, and the recent progress in petroleum refining, and the production of liquid fuels, chemicals, and materials using coal, methane, CO2 , biomass, and waste plastics is highlighted in combination with green carbon science. An outlook for these important fields is provided in the final section.
46 citations
TL;DR: This work illustrates the use of MOF thin films to tune the activity of an underlying CO2RR catalyst to produce further-reduced products.
Abstract: In tandem catalysis, two distinct catalytic materials are interfaced to feed the product of one reaction into the next one. This approach, analogous to enzyme cascades, can potentially be used to upgrade small molecules such as CO2 to more valuable hydrocarbons. Here, we investigate the materials chemistry of metal-organic framework (MOF) thin films grown on gold nanostructured microelectrodes (AuNMEs), focusing on the key materials chemistry challenges necessary to enable the applications of these MOF/AuNME composites in tandem catalysis. We applied two growth methods-layer-by-layer and solvothermal-to grow a variety of MOF thin films on AuNMEs and then characterized them using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The MOF@AuNME materials were then evaluated for electrocatalytic CO2 reduction. The morphology and crystallinity of the MOF thin films were examined, and it was found that MOF thin films were capable of dramatically suppressing CO production on AuNMEs and producing further-reduced carbon products such as CH4 and C2H4. This work illustrates the use of MOF thin films to tune the activity of an underlying CO2RR catalyst to produce further-reduced products.
46 citations
TL;DR: In this paper, the single-pass conversion of the reactants is another crucial system parameter that has received too little attention, and an electrolyzer that achieves high single pass conversion combined with high current density is proposed.
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TL;DR: This work applies a recently developed density functional theory-continuum approach based on the effective screening medium method and reference interaction site model to explore electrolyte effects with an enhanced description of the electrochemical interface and shows that the interdependence of voltage and pH leads to an unexpected change in adsorption site preference on Cu(001) terraces.
Abstract: Engineering the electrolyte microenvironment represents an attractive route to tuning the selectivity of electrocatalytic reactions beyond catalyst composition and morphology. However, harnessing t...
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