Sequential catalysis enables enhanced C-C coupling towards multi-carbon alkenes and alcohols in carbon dioxide reduction: a study on bifunctional Cu/Au electrocatalysts.

Electrochemical reduction of carbon dioxide (CO2) to multi-carbon products such as ethylene, ethanol and n-propanol offers a promising path for utilization of excessive CO2 and energy storage. Oxide-derived Cu electrodes are among the best electrocatalysts for the selective formation of ethylene and ethanol. However, a large fraction of the faradaic current still goes to hydrogen evolution, even at optimal conditions (electrolyte, potential, etc.). Here we employ the concept of sequential catalysis using judiciously designed CuAu bimetallic catalysts through galvanic exchange between Au3+ and Cu2O nanowires. By controlling the concentration of the Au3+ precursor and the exchange time, Au nanoparticles were evenly dispersed onto the Cu2O nanowires. The optimized oxide-derived CuAu catalyst showed remarkable improvement towards the formation of ethylene, ethanol and n-propanol, in terms of faradaic efficiency and current density. Our analysis of the electrochemical formation of carbon monoxide, ethylene and hydrogen suggests that the presence of Au, an electrocatalyst for CO2-to-CO conversion, helps enhance *CO-coverage on Cu, thus promoting the production of multi-carbon products and suppressing hydrogen formation on the CuAu catalyst. We propose promising strategies for designing electrochemical systems, which would enable the selective and scalable reduction of CO2 to ethylene and ethanol.

[1]  Yi-sheng Liu,et al.  Copper adparticle enabled selective electrosynthesis of n-propanol , 2018, Nature Communications.

[2]  Jeremy T. Feaster,et al.  Improved CO2 reduction activity towards C2+ alcohols on a tandem gold on copper electrocatalyst , 2018, Nature Catalysis.

[3]  J. Nørskov,et al.  Electrochemical Carbon Monoxide Reduction on Polycrystalline Copper: Effects of Potential, Pressure, and pH on Selectivity toward Multicarbon and Oxygenated Products , 2018, ACS Catalysis.

[4]  R. Quintero‐Bermudez,et al.  Steering post-C–C coupling selectivity enables high efficiency electroreduction of carbon dioxide to multi-carbon alcohols , 2018, Nature Catalysis.

[5]  Christine M. Gabardo,et al.  CO2 electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface , 2018, Science.

[6]  I. Sharp,et al.  The Technical and Energetic Challenges of Separating (Photo)Electrochemical Carbon Dioxide Reduction Products , 2018 .

[7]  The effects of currents and potentials on the selectivities of copper toward carbon dioxide electroreduction , 2018, Nature Communications.

[8]  Haotian Wang,et al.  Metal ion cycling of Cu foil for selective C–C coupling in electrochemical CO2 reduction , 2018, Nature Catalysis.

[9]  James E. Pander,et al.  Understanding the Heterogeneous Electrocatalytic Reduction of Carbon Dioxide on Oxide‐Derived Catalysts , 2018 .

[10]  Dan Ren,et al.  Practices for the collection and reporting of electrocatalytic performance and mechanistic information for the CO2 reduction reaction , 2017 .

[11]  Seunghwan Lee,et al.  Importance of Ag–Cu Biphasic Boundaries for Selective Electrochemical Reduction of CO2 to Ethanol , 2017 .

[12]  T. Jaramillo,et al.  Electrochemical CO2 Reduction over Compressively Strained CuAg Surface Alloys with Enhanced Multi-Carbon Oxygenate Selectivity. , 2017, Journal of the American Chemical Society.

[13]  Luo Gong,et al.  Continuous Production of Ethylene from Carbon Dioxide and Water Using Intermittent Sunlight , 2017 .

[14]  A. Bell,et al.  Optimizing C–C Coupling on Oxide-Derived Copper Catalysts for Electrochemical CO2 Reduction , 2017 .

[15]  Michael Grätzel,et al.  Solar conversion of CO2 to CO using Earth-abundant electrocatalysts prepared by atomic layer modification of CuO , 2017, Nature Energy.

[16]  F. Calle‐Vallejo,et al.  Spectroscopic Observation of a Hydrogenated CO Dimer Intermediate During CO Reduction on Cu(100) Electrodes. , 2017, Angewandte Chemie.

[17]  Yun Huang,et al.  Electrochemical Reduction of CO2 Using Copper Single-Crystal Surfaces: Effects of CO* Coverage on the Selective Formation of Ethylene , 2017 .

[18]  B. Yeo,et al.  Tuning the Selectivity of Carbon Dioxide Electroreduction toward Ethanol on Oxide-Derived CuxZn Catalysts , 2016 .

[19]  Yun Huang,et al.  Mechanistic Insights into the Selective Electroreduction of Carbon Dioxide to Ethylene on Cu2O-Derived Copper Catalysts , 2016 .

[20]  G. Mul,et al.  Palladium-gold catalyst for the electrochemical reduction of CO2 to C1-C5 hydrocarbons. , 2016, Chemical communications.

[21]  E. Stach,et al.  Highly selective plasma-activated copper catalysts for carbon dioxide reduction to ethylene , 2016, Nature Communications.

[22]  J. Ager,et al.  Tailoring Copper Nanocrystals towards C2 Products in Electrochemical CO2 Reduction. , 2016, Angewandte Chemie.

[23]  Yun Huang,et al.  Mechanistic Insights into the Enhanced Activity and Stability of Agglomerated Cu Nanocrystals for the Electrochemical Reduction of Carbon Dioxide to n-Propanol. , 2016, The journal of physical chemistry letters.

[24]  Paul J. A. Kenis,et al.  One-step electrosynthesis of ethylene and ethanol from CO2 in an alkaline electrolyzer , 2016 .

[25]  Seunghwan Lee,et al.  Electrocatalytic Production of C3-C4 Compounds by Conversion of CO2 on a Chloride-Induced Bi-Phasic Cu2O-Cu Catalyst. , 2015, Angewandte Chemie.

[26]  Alexis T. Bell,et al.  Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels , 2015, Proceedings of the National Academy of Sciences.

[27]  Matthew W. Kanan,et al.  Probing the Active Surface Sites for CO Reduction on Oxide-Derived Copper Electrocatalysts. , 2015, Journal of the American Chemical Society.

[28]  Antonio Abate,et al.  Efficient photosynthesis of carbon monoxide from CO2 using perovskite photovoltaics , 2015, Nature Communications.

[29]  Anders Nilsson,et al.  High selectivity for ethylene from carbon dioxide reduction over copper nanocube electrocatalysts. , 2015, Angewandte Chemie.

[30]  Chunguang Chen,et al.  Selective Electrochemical Reduction of Carbon Dioxide to Ethylene and Ethanol on Copper(I) Oxide Catalysts , 2015 .

[31]  G. Mul,et al.  Manipulating the Hydrocarbon Selectivity of Copper Nanoparticles in CO2 Electroreduction by Process Conditions , 2015 .

[32]  Jae Kwang Lee,et al.  Insights into an autonomously formed oxygen-evacuated Cu2O electrode for the selective production of C2H4 from CO2. , 2015, Physical chemistry chemical physics : PCCP.

[33]  Chunguang Chen,et al.  Stable and selective electrochemical reduction of carbon dioxide to ethylene on copper mesocrystals , 2015 .

[34]  Thomas F. Jaramillo,et al.  Electrocatalytic conversion of carbon dioxide to methane and methanol on transition metal surfaces. , 2014, Journal of the American Chemical Society.

[35]  G. Mul,et al.  Electrochemical CO2 reduction on Cu2O-derived copper nanoparticles: controlling the catalytic selectivity of hydrocarbons. , 2014, Physical chemistry chemical physics : PCCP.

[36]  Matthew W. Kanan,et al.  Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper , 2014, Nature.

[37]  F. Calle‐Vallejo,et al.  Theoretical considerations on the electroreduction of CO to C2 species on Cu(100) electrodes. , 2013, Angewandte Chemie.

[38]  Marc T. M. Koper,et al.  Theory of multiple proton–electron transfer reactions and its implications for electrocatalysis , 2013 .

[39]  M. Koper,et al.  Structure Sensitivity of the Electrochemical Reduction of Carbon Monoxide on Copper Single Crystals , 2013 .

[40]  Matthew W. Kanan,et al.  Aqueous CO2 reduction at very low overpotential on oxide-derived Au nanoparticles. , 2012, Journal of the American Chemical Society.

[41]  M. Koper,et al.  Two pathways for the formation of ethylene in CO reduction on single-crystal copper electrodes. , 2012, Journal of the American Chemical Society.

[42]  Thomas F. Jaramillo,et al.  New insights into the electrochemical reduction of carbon dioxide on metallic copper surfaces , 2012 .

[43]  Matthew W Kanan,et al.  CO2 reduction at low overpotential on Cu electrodes resulting from the reduction of thick Cu2O films. , 2012, Journal of the American Chemical Society.

[44]  Andrew A. Peterson,et al.  Activity Descriptors for CO2 Electroreduction to Methane on Transition-Metal Catalysts , 2012 .

[45]  M. Koper,et al.  Electrochemical reduction of carbon dioxide on copper electrodes , 2017 .

[46]  Andrew A. Peterson,et al.  How copper catalyzes the electroreduction of carbon dioxide into hydrocarbon fuels , 2010 .

[47]  N. Lewis,et al.  Powering the planet: Chemical challenges in solar energy utilization , 2006, Proceedings of the National Academy of Sciences.

[48]  Y. Hori,et al.  Electrochemical reduction of carbon dioxide at various series of copper single crystal electrodes , 2003 .

[49]  Y. Hori,et al.  Electrochemical reduction of CO2 at copper single crystal Cu(S)-[n(111)×(111)] and Cu(S)-[n(110)×(100)] electrodes , 2002 .

[50]  Akira Murata,et al.  Electrochemical Reduction of CO at a Copper Electrode , 1997 .

[51]  Allen J. Bard,et al.  Artificial Photosynthesis: Solar Splitting of Water to Hydrogen and Oxygen , 1995 .

[52]  Toshio Tsukamoto,et al.  Electrocatalytic process of CO selectivity in electrochemical reduction of CO2 at metal electrodes in aqueous media , 1994 .

[53]  Y. Hori,et al.  Formation of hydrocarbons in the electrochemical reduction of carbon dioxide at a copper electrode in aqueous solution , 1990 .