Surface Adsorbed Hydroxyl: A Double-Edged Sword in Electrochemical CO2 Reduction over Oxide-Derived Copper |
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| Authors: | Daixing Wei Yiqing Wang Prof Chung-Li Dong Ta Thi Thuy Nga Yuchuan Shi Jialin Wang Xiaoli Zhao Prof Fan Dong Prof Shaohua Shen |
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| Institution: | 1. International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, 710049 China;2. Department of Physics, Tamkang University, New Taipei City, 25137 Taiwan;3. Research Center for Environmental and Energy Catalysis, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 611731 China |
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| Abstract: | Oxide-derived Cu (OD?Cu) featured with surface located sub-20 nm nanoparticles (NPs) created via surface structure reconstruction was developed for electrochemical CO2 reduction (ECO2RR). With surface adsorbed hydroxyls (OHad) identified during ECO2RR, it is realized that OHad, sterically confined and adsorbed at OD?Cu by surface located sub-20 nm NPs, should be determinative to the multi-carbon (C2) product selectivity. In situ spectral investigations and theoretical calculations reveal that OHad favors the adsorption of low-frequency *CO with weak C≡O bonds and strengthens the *CO binding at OD?Cu surface, promoting *CO dimerization and then selective C2 production. However, excessive OHad would inhibit selective C2 production by occupying active sites and facilitating competitive H2 evolution. In a flow cell, stable C2 production with high selectivity of ～60 % at ?200 mA cm?2 could be achieved over OD?Cu, with adsorption of OHad well steered in the fast flowing electrolyte. |
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| Keywords: | CO2 Reduction Electrochemistry Oxide-Derived Copper Reaction Mechanisms Surface Adsorbed Hydroxyls |
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