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.

Prussian blue analogs (PBAs) are especially investigated as superior cathodes for sodium‐ion batteries (SIBs) due to high theoretical capacity (≈170 mA h g−1) with 2‐Na storage and low cost. However, PBAs suffer poor cyclability due to irreversible phase transition in deep charge/discharge states. PBAs also suffer low crystallinity, with considerable [Fe(CN)6] vacancies, and coordinated water in crystal frameworks. Presently, a new chelating agent/surfactant coassisted crystallization method is developed to prepare high‐quality (HQ) ternary‐metal NixCo1−x[Fe(CN)6] PBAs. By introducing inactive metal Ni to suppress capacity fading caused by excessive lattice distortion, these PBAs have tunable limits on depth of charge/discharge. HQ‐NixCo1−x[Fe(CN)6] (x = 0.3) demonstrates the best reversible Na‐storage behavior with a specific capacity of ≈145 mA h g−1 and a remarkably improved cycle performance, with ≈90% capacity retention over 600 cycles at 5 C. Furthermore, a dual‐insertion full cell on the cathode and NaTi2(PO4)3 anode delivers reversible capacity of ≈110 mA h g−1 at a current rate of 1.0 C without capacity fading over 300 cycles, showing promise as a high‐performance SIB for large‐scale energy‐storage systems. The ultrastable cyclability achieved in the lab and explained herein is far beyond that of any previously reported PBA‐based full cells.

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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Metal–organic frameworks (MOFs), such as Prussian blue and its analogues (PB and PBAs) with open frameworks have attracted tremendous attentions as cathode materials for sodium‐ion batteries, owing to their simple method of synthesis and high theoretical specific capacity. In this study, core–shell‐structured PBAs are prepared by an in situ self‐assembly method. Owing to the advantages of both constituents, the as‐prepared core–shell PBAs show excellent rate and cycling electrochemical properties through a dual‐level‐controlled charge–discharge depth mechanism. It delivers a specific capacity of 104.3 mAh g−1 at 0.1 C, as well as a remarkably enhanced cycle performance, giving 88.3 % of its initial capacity over 1000 cycles at 300 mA g−1. In particular, the coating strategy described herein could be extended to other MOF materials, leading to wider application in energy storage.