Trace Ionic Liquid-Assisted Orientational Growth of Cu2 O (110) Facets Promote CO2 Electroreduction to C2 Products.

Cu2 O has great advantages for CO2 electroreduction to C2 products, of which the activity and selectivity are closely related to its crystal facets. In this work, density functional theory calculation indicated that the (110) facets of Cu2 O had a lower energy barrier for the C-C coupling compared to the (100) and (111) facets. Therefore, Cu2 O(110) facets were successfully synthesized with the assistance of trace amounts of the ionic liquid 1-butyl-3-methylimidazolium ([Bmim]BF4 ) by a sample wet-chemical method. A high faradaic efficiency of 71.1 % and a large current density of 265.1 mA cm-2 toward C2 H4 and C2 H5 OH were achieved at -1.1 V (vs. reversible hydrogen electrode) in a flow cell. The in situ and electrochemical analysis indicated that it possessed the synergy effects of strong adsorption of *CO2 and *CO, large active area, and excellent conductivity. This study provided a new way to enhance the C2 selectivity of CO2 electroreduction on Cu2 O by crystal structure engineering.

Bionic Construction of Helical Bi2 O3 Microfibers for Highly Efficient CO2 Electroreduction.

Helical Bi2 O3 microfibers (HBM) were prepared with the assistance of cotton template through a simple heating treatment in air. This twisted structure induced the lattice strains, enriched the oxygen vacancies of Bi2 O3 , and promoted the sufficient exposure of active sites simultaneously, thus performing outstanding activity and selectivity as catalyst for CO2 electroreduction to formate. The faradaic efficiency (FE) of formate reached 100.4±1.9 % at -0.90 V vs. reversible hydrogen electrode (RHE) in an H-cell, and the partial current density was boosted to 226 mA cm-2 with FEformate of 96 % at -1.08 V vs. RHE in a flow cell. This work may open a new era for construction of metal oxide fibers by bionic strategy as high-performance electrocatalysts.

UV-Light-Induced Surface Reconstruction of Cubic Cu2 O Promotes CO2 Electroreduction to C2 Products.

Carbon dioxide electroreduction has been considered as one of the most appealing ways to reducing the CO2 emission but raising the selectivity of high-value added products like C2+ still faces great challenge. Herein, we report a convenient way to modify the cubic Cu2 O particles through UV-light irradiation induced reduction in a solution containing H2 O2 and i-propanol. The plane surface of Cu2 O was reconstructed to roughness shell composed of abandant grain boundaries, in which the ration of Cu+ /Cu0 can be easily regulated by controlling the irradiation time. At the same time, the increasing electrochemical active surface area facilitated the exposure of active sites. Combining of above factors, the Faradaic efficiency of C2 (ethylene and ethanol) from CO2 electroreduction was greatly increased to 62.56% with a high partial current density of 145 mA cm-2 . Our work put forward a facile method for the fine control of the surface structure of cuprous oxide and a novel platform to elucidate the synergistic effects of Cu+ /Cu0 on CO2 electroreduction.