Currently, more than 80% of the world’s energy needs are met by burning fossil fuels. Supplies of these fuels are intrinsically limited and will eventually run out. Combustion of fossil fuels also generates carbon dioxide, whose rapidly increasing atmospheric concentration is suspected to be an accelerant of global warming. One solution for reducing atmospheric CO₂ levels is carbon capture and sequestration. Another is to electrochemically reduce the CO₂ into chemical feedstocks and fuels. If the energy used for these processes is generated from renewable sources such as solar and wind, we can envisage a chemical production cycle that is closed-loop with net zero carbon emission.

In this talk, we shall share our recent works related to the development of copper-based catalysts (including Cu single crystal surfaces, doped Cu, etc.) for the selective electroreduction of CO₂ to compounds such as formic acid, ethylene, ethanol and propanol. We shall discuss factors that gave Cu₂O-derived Cu catalysts the ability to selectively reduce CO₂ to ethylene. We shall show that this ability can be correlated to the crystallite sizes of the Cu₂O-derived Cu particles. We shall also present a new class of CO₂ reduction catalysts made from Cu and Zn, which is highly selective towards the formation of ethanol. A two-site mechanism to rationalize the selectively is proposed. Finally, we present an overview of our recent efforts to couple photovoltaics to an electrocatalytic cell for the solar-driven reduction of carbon dioxide.

References:

1. Yun Huang, Albertus Denny Handoko, Pussana Hirunsit and Boon Siang Yeo. Electrochemical Reduction of CO₂ Using Copper Single-Crystal Surfaces: Effects of CO* Coverage on the Selective Formation of Ethylene. ACS Catal., 2017, 7, 1749-1756.
2. Dan Ren, Bridget Su-Hui Ang and Boon Siang Yeo. Tuning the Selectivity of Carbon Dioxide Electroreduction towards Ethanol on Oxide-Derived Cu_xZn Catalysts. ACS Catal. 2016, 6, 8239-8247. 
3. Albertus D. Handoko, Cheng Wai Ong, Yun Huang, Zheng Guang Lee, Liyi Lin, Grace B. Panetti, and Boon Siang Yeo. Mechanistic Insights into the Selective Electroreduction of Carbon Dioxide to Ethylene on Cu₂O-Derived Copper Catalysts. J. Phy. Chem. C 2016, 120, 20058-20067.
4. Dan Ren, Nian Tee Wong, Albertus Denny Handoko, Yun Huang and Boon Siang Yeo. Mechanistic Insights into the Enhanced Activity and Stability of Agglomerated Cu Nanocrysals for the Electrochemical Reduction of Carbon Dioxide to n-Propanol. J. Phy. Chem. Lett. 2016, 7, 20.