Electrochemical carbon dioxide reduction reaction (CO2RR) offers a promising way of effectively converting CO2 to value‐added chemicals and fuels by utilizing renewable electricity. To date, the electrochemical reduction of CO2 to single‐carbon products, especially carbon monoxide and formate, has been well achieved. However, the efficient conversion of CO2 to more valuable multicarbon products (e.g., ethylene, ethanol, n‐propanol, and n‐butanol) is difficult and still under intense investigation. Here, recent progresses in the electrochemical CO2 reduction to multicarbon products using copper‐based catalysts are reviewed. First, the mechanism of CO2RR is briefly described. Then, representative approaches of catalyst engineering are introduced toward the formation of multicarbon products in CO2RR, such as composition, morphology, crystal phase, facet, defect, strain, and surface and interface. Subsequently, key aspects of cell engineering for CO2RR, including electrode, electrolyte, and cell design, are also discussed. Finally, recent advances are summarized and some personal perspectives in this research direction are provided.

Electrocatalytic carbon dioxide reduction reaction (CO2RR) holds significant potential to promote carbon neutrality. However, the selectivity toward multicarbon products in CO2RR is still too low to meet practical applications. Here the authors report the delicate synthesis of three kinds of Ag–Cu Janus nanostructures with {100} facets (JNS‐100) for highly selective tandem electrocatalytic reduction of CO2 to multicarbon products. By controlling the surfactant and reduction kinetics of Cu precursor, the confined growth of Cu with {100} facets on one of the six equal faces of Ag nanocubes is realized. Compared with Cu nanocubes, Ag65–Cu35 JNS‐100 demonstrates much superior selectivity for both ethylene and multicarbon products in CO2RR at less negative potentials. Density functional theory calculations reveal that the compensating electronic structure and carbon monoxide spillover in Ag65–Cu35 JNS‐100 contribute to the enhanced CO2RR performance. This study provides an effective strategy to design advanced tandem catalysts toward the extensive application of CO2RR.

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The aprotic Li-CO 2 battery is emerging as a promising energy storage technology with the capability of CO 2 fixation and conversion. However, its practical applications are still impeded by the large overpotential. Herein, the general synthesis of a series of ultrathin 2D Ru-M (M = Co, Ni, and Cu) nanosheets by a facile one-pot solvothermal method is reported. As a proofof-concept application, the representative RuCo nanosheets are used as the cathode catalysts for Li-CO 2 batteries, which demonstrate a low charge voltage of 3.74 V, a small overpotential of 0.94 V, and hence a high energy efficiency of 75%. Ex/in situ studies and density functional theory calculations reveal that the excellent catalytic performance of RuCo nanosheets originates from the enhanced adsorption toward Li and CO 2 during discharge as well as the elevated electron interaction with Li 2 CO 3 during charge by the in-plane RuCo alloy structure. This work indicates the feasibility of boosting the electrochemical performance of Li-CO 2 batteries by in-plane metal alloy sites of ultrathin 2D alloy nanomaterials.

An effective, nondestructive, and universal strategy to homogeneously modify freestanding carbon nanotube (CNT) films with various active species is essential to achieve functional electrodes for flexible electrochemical energy storage, which is challenging and has attracted considerable research interest. In this work, a generalizable concept, to utilize silicon oxide as the intermediate to uniformly decorate various metal sulfide nanostructures throughout CNT films is reported. Taking nickel sulfide nanosheet/CNT (NS/CNT) films, in which the NS nanosheets are homogeneously attached on the intact few‐walled CNTs, as an example, the sheet‐like NS provides sufficient active sites for redox reactions and the CNT network acts as an efficient electron highway, maintaining the structural integrity of the composite and also buffering volume changes. These merits enable NS/CNT films to meet the requirements of versatile energy storage applications. When used for supercapacitors, a high specific capacitance (2699.7 F g−1/10 A g−1), outstanding rate performance at extremely high rates (1527 F g−1/250 A g−1), remarkable cycling stability, and excellent flexibility can be achieved, among the best performance so far. Moreover, it also delivers excellent performance in the storage of Li and Na ions, meaning it is also potentially suitable for Li/Na ion batteries.