In an interview, Dohyung Kim with Chemical Today Magazine speaks about his research - studying the mechanisms of carbon dioxide transformation, with the goal to build systems capable of providing valuable products at efficient rates for various needs, using atmospheric carbon dioxide as the source to overcome the intermittency of renewable energy sources.
Research insight.
My research focuses on developing nanoparticle-based electrocatalysts for converting carbon dioxide to various carbon-based products, ranging from simple products like carbon monoxide to more complex products such as ethylene and ethanol. With a detailed understanding of the underlying mechanisms of carbon dioxide transformation, the ultimate goal is to build systems capable of providing valuable products at efficient rates for various needs, using atmospheric carbon dioxide as the source. By combining with electricity generated from renewable sources, such as solar electricity, this technology can be an effective way to overcome the intermittency of renewable energy sources and mitigate the impacts of high carbon dioxide concentration in the atmosphere by closing up the carbon cycle.
Use of copper nanoparticles in the research.
Copper nanoparticles are the catalytic materials used for transforming carbon dioxide to carbon-based products. Electrical bias is applied to the substrate supported copper nanoparticles in aqueous media and dissolved carbon dioxide is catalytically converted on their surfaces. Copper has been known so far as the only element capable of generating various types of C1 to C3products. Therefore, investigating the effect of nanoscale morphology of copper on its product selectivity and catalytic turnover has led to identifying certain structural motifs that tend to favour specific products, such as methane.
More recently, my research focus has shifted away from using these Cu nanoparticles directly as electrocatalysts. Instead, Cu nanoparticles are used as precursors to a catalytic material that has unique activity for facilitating carbon-carbon bonds from CO2. Given the right conditions, such as the nanoparticle density/proximity and electrochemical environment, large numbers of copper nanoparticles structurally transform to a nanostructured copper-based catalyst active for multicarbon product formation.
Impact of overpotential on the catalysts.
As overpotential is a measure of additional energy cost to drive a certain reaction, we typically want catalysts that have the least amount of overpotentials at sufficient production rates. This would apply to various electrocatalytic reactions, such as hydrogen and oxygen evolution from water splitting. While there has been some progress of bringing the overpotentials to reasonable levels in these reactions, electrochemical CO2 reduction still suffers from large overpotentials that are needed. Not only the production rates are sluggish without additional application of overpotentials, but multicarbon (C2-C3) products don`t even form below certain overpotential levels. These levels have been typically around 1 volt, which makes the CO2 conversion process energetically inefficient. In order to achieve a viable method for electrolytic CO2 to multicarbon transformation, the overpotential has to be lowered significantly. My latest research on the discovery of an active catalyst from copper nanoparticle ensembles has shown that we can reduce the overpotentials by around 300mV, which has been quite difficult.
Read more: A new direction towards carbon management
In an interview, Dohyung Kim with Chemical Today Magazine speaks about his research - studying the mechanisms of carbon dioxide transformation, with the goal to build systems capable of providing valuable products at efficient rates for various needs, using atmospheric carbon dioxide as the source to overcome the intermittency of renewable energy sources.
Research insight.
My research focuses on developing nanoparticle-based electrocatalysts for converting carbon dioxide to various carbon-based products, ranging from simple products like carbon monoxide to more complex products such as ethylene and ethanol. With a detailed understanding of the underlying mechanisms of carbon dioxide transformation, the ultimate goal is to build systems capable of providing valuable products at efficient rates for various needs, using atmospheric carbon dioxide as the source. By combining with electricity generated from renewable sources, such as solar electricity, this technology can be an effective way to overcome the intermittency of renewable energy sources and mitigate the impacts of high carbon dioxide concentration in the atmosphere by closing up the carbon cycle.
Use of copper nanoparticles in the research.
Copper nanoparticles are the catalytic materials used for transforming carbon dioxide to carbon-based products. Electrical bias is applied to the substrate supported copper nanoparticles in aqueous media and dissolved carbon dioxide is catalytically converted on their surfaces. Copper has been known so far as the only element capable of generating various types of C1 to C3products. Therefore, investigating the effect of nanoscale morphology of copper on its product selectivity and catalytic turnover has led to identifying certain structural motifs that tend to favour specific products, such as methane.
More recently, my research focus has shifted away from using these Cu nanoparticles directly as electrocatalysts. Instead, Cu nanoparticles are used as precursors to a catalytic material that has unique activity for facilitating carbon-carbon bonds from CO2. Given the right conditions, such as the nanoparticle density/proximity and electrochemical environment, large numbers of copper nanoparticles structurally transform to a nanostructured copper-based catalyst active for multicarbon product formation.
Impact of overpotential on the catalysts.
As overpotential is a measure of additional energy cost to drive a certain reaction, we typically want catalysts that have the least amount of overpotentials at sufficient production rates. This would apply to various electrocatalytic reactions, such as hydrogen and oxygen evolution from water splitting. While there has been some progress of bringing the overpotentials to reasonable levels in these reactions, electrochemical CO2 reduction still suffers from large overpotentials that are needed. Not only the production rates are sluggish without additional application of overpotentials, but multicarbon (C2-C3) products don`t even form below certain overpotential levels. These levels have been typically around 1 volt, which makes the CO2 conversion process energetically inefficient. In order to achieve a viable method for electrolytic CO2 to multicarbon transformation, the overpotential has to be lowered significantly. My latest research on the discovery of an active catalyst from copper nanoparticle ensembles has shown that we can reduce the overpotentials by around 300mV, which has been quite difficult.
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