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Summary: The production of CO via electrochemical CO2 reduction has been recognised as a promising technology that overcomes the environmental issues caused by global warming. It also facilitates the conversion of CO2 into energy sources. Earth‐abundant Zn is a well‐known alternative to noble metal catalysts such as Au and Ag for the electrochemical CO2 reduction to CO. In particular, Zn‐based materials in the form of nanowires are potentially applicable as electrocatalysts in the electrochemical CO2 reduction. However, the conventional methods for manufacturing the nanowire structure are difficult as they require harsh conditions such as high temperatures and excess energy. In this study, Zn‐based nanowire catalysts are prepared by the facile electrodeposition of Zn nanostructures on a substrate followed by their energy‐free solution‐phase reconstitution. Further, their electrochemical performance in the CO2 reduction is investigated in a CO2‐purged 0.5 M KHCO3 electrolyte. By optimising the deposition conditions, hexagonal Zn (h‐Zn) plates with dominant Zn(101) facets, the favoured crystal structure for CO2 reduction, are fabricated on carbon paper. Furthermore, it is found that, during the solution‐phase reconstruction over 16 hours, the h‐Zn plate transforms to a nanowire owing to the differences between the oxidation rates of different crystal facets and the formation of a hydroxide complex. The activity of the reconstructed Zn‐based nanowire catalyst is enhanced further by forming an oxide layer via thermal treatment in a H2 atmosphere. This treatment boosted the reaction kinetics, thereby enhancing the catalyst performance in the CO2 reduction. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction reaction (CRR) is a promising way to convert carbon dioxide (CO2) into value‐added hydrocarbons to alleviate the ever‐increasing environmental problem and accelerate the realization of carbon cycling. Cost‐effective and stable electrocatalytic materials with low overpotential, superior selectivity, excellent activity and great stability are critically important to achieve such a target. Cu‐based electrocatalysts are promising candidates for electrochemical CRR due to their versatile abilities of converting CO2 into various products. This review analyzes and summarizes the current progress in utilization of Cu‐based catalytic materials for electrochemical CRR. Monometallic, bimetallic, trimetallic, and multimetallic Cu‐based electrocatalysts with variable elemental compositions and tunable morphologies, including Cu nanowires, Cu nanocubes (NCs), Cu porous structures, Cu‐based alloys, Cu‐oxide/hydrogen oxide, Cu single atoms, and 2D substrate‐supported Cu electrocatalysts for CRR, are surveyed. Substantial advances in overcoming the existing bottlenecks of eletrocatalysts and effectively improving CRR performance of Cu‐based electrocatalysts for future applications are systematically discussed. Challenges and perspectives of Cu‐based electrocatalytic materials for CRR are also offered, which may shed light on further development of Cu‐based electrocatalysts with superior performance. It is anticipated that this review will provide a valuable insight into the rational design and synthesis of highly efficient Cu‐based electrocatalysts for large‐scale CRR utilization. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide (CO2) to CO is regarded as an efficient method to utilize the greenhouse gas CO2, because the CO product can be further converted into high value‐added chemicals via the Fisher–Tropsch process. Among all electrocatalysts used for CO2‐to‐CO reduction, Au‐based catalysts have been demonstrated to possess high selectivity, but their precious price limits their future large‐scale applications. Thus, simultaneously achieving high selectivity and reasonable price is of great importance for the development of Au‐based catalysts. Here, we report Ag@Au core–shell nanowires as electrocatalyst for CO2 reduction, in which a nanometer‐thick Au film is uniformly deposited on the core Ag nanowire. Importantly, the Ag@Au catalyst with a relative low Au content can drive CO generation with nearly 100 % Faraday efficiency in 0.1 m KCl electrolyte at an overpotential of ca. −1.0 V. This high selectivity of CO2 reduction could be attributed to a suitable adsorption strength for the key intermediate on Au film together with the synergistic effects between the Au shell and Ag core and the strong interaction between CO2 and Cl− ions in the electrolyte, which may further pave the way for the development of high‐efficiency electrocatalysts for CO2 reduction. [ABSTRACT FROM AUTHOR]