The importance of surface morphology in controlling the selectivity of polycrystalline copper for CO2 electroreduction
ABSTRACT This communication examines the effect of the surface morphology of polycrystalline copper on electroreduction of CO(2). We find that a copper nanoparticle covered electrode shows better selectivity towards hydrocarbons compared with the two other studied surfaces, an electropolished copper electrode and an argon sputtered copper electrode. Density functional theory calculations provide insight into the surface morphology effect.
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ABSTRACT: Here we review recent developments and technological advances in the field of electrochemical reduction of carbon dioxide to fuels, energy carriers and precursors and other interesting building blocks for industrial applications. Synthetic hydrocarbon fuels derived from CO2/H2O are proposed as alternatives to hydrogen as an energy carrier that enables a carbon-neutral energy cycle, given their inherent advantages of high H/C ratio and convenience of storage and transportation. The electrochemical reduction of CO2 represents a feasible route for the direct generation of hydrocarbon fuels or their precursors (i.e., synthesis gas) using CO2/H2O. Such hydrocarbons fit well within the existing energy infrastructure because of their similarity to existing fossil fuels. Recently significant efforts are being devoted to the development of prototype systems, such as low- or high- temperature electrolyzers that operate as part of environmentally sustainable energy networks.03/2015; 3(3). DOI:10.1002/ente.201402166
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ABSTRACT: Various CuxO catalysts with different special microstructures were synthesized using a simple one-step hydrothermal method by controlling the reaction time and temperature conditions. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) were used to observe the morphologies of the received catalysts. The 3-dimensional (3D) hierarchical nanospheres (500 nm) comprised of secondary structured nanorods (50 nm) are formed at 180 degrees C for 2 hours. However, when increasing the hydrothermal reaction temperature to 220 degrees C, solid microspheres with a large size of 2.5 mu m begin to appear instead of flabby hierarchical nanospheres. To further investigate the effect of morphologies on the activity and production selectivity of CuxO catalysts, cyclic voltammetry (CV) was used to evaluate the onset potential and current density of catalyzed CO2 reduction combining linear sweep voltammetry (LSV) in 0.5 M KHCO3 solution. The effect of catalyst loading was also tested by applying the gas diffusion layer (GDL) to make up a working electrode for CO2 electroreduction. The results indicate that the synthesized temperature of 180 degrees C for 2 h is the optimal condition for CuxO nanospheres and the optimal loading is about 3 mg cm(-2), under which the onset potential for CO2 electroreduction reaches -0.55 V vs. SHE. By ion chromatography measurement, the faradaic efficiency and production rate of produced formate was found to be 59%, which is much higher than most reported Cu-based catalysts at the same electrolysis conditions, indicating the high selectivity of the CuxO nanospheres due to their controlled special surface morphology.RSC Advances 01/2014; 4(84):44583-44591. DOI:10.1039/C4RA09442E · 3.71 Impact Factor
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ABSTRACT: The product distribution of electrochemical reduction of CO2 can be altered by modifying the surface of pure copper by deposition. In this study, chronoamperometric deposition of Cu on Cu (Cu/Cu) was carried out at two different CuSO4 bath concentrations, 0.25 M (high) and 0.025 M (low), termed as Cu/Cu-H and Cu/Cu-L respectively. These deposits were characterized by X-ray diffraction and they vary in their crystal orientation. Pure Cu and Cu/Cu were aligned towards (1 1 1) and (2 2 0) plane with a texture coefficient of 1.2 and 1.7, respectively. Electrodeposited electrodes were tested for the electrochemical reduction of CO2 in KCl electrolyte and the results were compared with that of pure Cu electrode. Electrochemical reduction of CO2 showed methane and ethane, with hydrogen as the byproduct. The product distribution varied with the crystal orientation of Cu electrodes. The maximum Faradaic efficiency of methane was 26% obtained on pure Cu electrode with (1 1 1) and (2 0 0) orientation, whereas Cu/Cu-L with dominating (2 2 0) orientation showed a maximum formation of ethane with Faradaic efficiency of 43%. A possible mechanism of product formation on Cu towards C1 and Cu/Cu towards C2 is also discussed.Catalysis Today 05/2015; 245. DOI:10.1016/j.cattod.2014.08.008 · 3.31 Impact Factor