The development of efficient electrocatalysts for the CO 2 reduction reaction (CO 2 RR) remains ac hallenge.D emonstrated here is aN iSn atomic-pair electrocatalyst (NiSn-APC) on ah ierarchical integrated electrode,w hich exhibits as ynergistic effect in simultaneously promoting the activity and selectivity of the CO 2 RR to formate.The NiSn atomic pair consists of adjacent Ni and Sn, eachc oordinated with four nitrogen atoms (N 4-Ni-Sn-N 4). The as-prepared NiSn-APC displays exceptional activity for the CO 2 RR to formate with at urnover frequency of 4752 h À1 ,aformate productivity of 36.7 mol h À1 g Sn À1 and an utilization degree of active sites (57.9 %), which are superior to previously reported singleatomic catalysts.B oth experimental data and density-functional theory calculations verify the electron redistribution of Sn imposed by adjacent Ni, which reduces the energy barrier of the *OCHO intermediate and makes this potential-determining step thermodynamically spontaneous.This synergistic catalysis provides as uccessful paradigm for rational design and preparation of atomic-pair electrocatalysts with enhanced performance.

Electrochemical nitrate reduction to ammonia is a promising alternative strategy to the traditional Haber-Bosch process but suffers from a low Faradaic efficiency and limited ammonia yield due to the sluggish multi-electron/proton-involved steps. Herein, we report a typical hollow cobalt phosphide nanosphere electrocatalyst assembled on a self-supported carbon nanosheet array synthesized with a confinement strategy that exhibits an extremely high ammonia yield rate of 8.47 mmol h−1 cm−2 through nitrate reduction reaction, which is highly superior to previously reported values to our knowledge. In situ experiments and theoretical investigations reveal that the dynamic equilibrium between the generation of active hydrogen on cobalt phosphide and its timely consumption by nitrogen intermediates leads to a superior ammonia yield with a high Faradaic efficiency. This unique insight based on active hydrogen equilibrium provides new opportunities for large-scale ammonia production through electrochemical techniques and can be further used for carbon dioxide capture.

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Single‐atomic electrocatalysts (SACs) have shown great promise in electrocatalysis fields owing to their theoretical maximum atom utilization (100%). Yet still, it is far from expectation in practical applications due to entrapping within supports and blocking by aggregation. Herein, self‐supported carbon nanosheet arrays consisting of single‐atomic Co electrocatalyst (SS‐Co‐SAC) toward oxygen‐involved reaction and zinc–air batteries are reported. Impressively, the as‐synthesized SS‐Co‐SAC gives a markedly enhanced utilization of active sites (≈22.3%@2.3 wt%) as a result of single‐atomic dispersion of Co within a unique nanosheet arrays architecture, which is the largest value among other reported results. Benefiting from the high utilization of active sites, the SS‐Co‐SAC electrode exhibits outstanding electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Notably, the turnover frequency value for ORR is determined to be ≈9.26 s−1, which stands for the highest level among noble metal‐free electrocatalysts reported previously. Moreover, as an air‐cathode for zinc–air batteries with SS‐Co‐SAC, a power density of 195.1 mW cm−2 and a robust durability are achieved. It is believed that this study would guide the future design of highly active and durable single‐atom catalysts for both fundamental research and practical applications.

performance of Li-S batteries is still restricted by poor conductivity of sulfur itself and discharge products (Li 2 S/Li 2 S 2 ), which makes hard conversion of sulfur. Additionally, the common shuttle effect of intermediate polysulfide also leads to an obvious capacity loss during charging and discharging. [10][11][12][13][14][15] Thus, new strategies are urgent in addressing the problems of high-capacity sulfur cathodes for Li-S batteries.To design high-performance cathode, dispersing nanostructured sulfur particles on carbon materials have attracted particular interests, which not only stabilize sulfur and intermediates but also promotes electron transfer during charging/ discharging. [16][17][18][19][20][21] Although carbon materials have been the first choice to disperse sulfur particles, the nonpolar carbon suffers a weak binding force to the intermediate product, which results in serious shuttle effect and making it difficult to reuse the polysulfide (Scheme 1a). To address these issues, plenty of work has begun to focus on the modification of nonpolar carbon by introducing heteroatoms (B, N, O, or S). [22][23][24][25] This is because the lone pair of electrons on the heteroatoms forms an electrostatic attraction (Li bond) with the polysulfide, which can effectively prevent shuttle of polysulfides. [26,27] However, the high loading and the easy aggregation of sulfur are hard to be balanced, since sulfur are getting easier to migrate and aggregate at surface of carbon supports, which lead to the low concentration loading or limited sulfur utilization. Therefore, sulfur confinement and simultaneous highly efficient conversion remains a challenge for the next-generation Li-S batteries.Herein, we develop honeycomb-like mesoporous carbon nanosheets (MC-NS) with abundant defects and Co-N-C catalytic site as efficient host for simultaneously confinement and efficient conversion of polysulfides, which shows significantly enhanced performance for Li-S batteries cathode (Scheme 1b). The as-prepared MC-NS exhibits an excellent 2D conductive network with a high specific surface area of 335.4 m 2 g −1 and abundant mesopores that provide high storage space and expansion space for sulfur. Moreover, the density functional theory (DFT) calculation and experiments manifest that the presence of abundant defects on the carbon skeleton MC-Ns Lithium-sulfur (Li-S) batteries have attracted increasing attention due to their extremely high theoretical specific capacity and a promising power density. However, practical applications of Li-S batteries are still limited by the relatively low performance, owing to poor conductivity of sulfur itself and discharge products (Li 2 S/Li 2 S 2 ) as well as the shuttle effect of the intermediate polysulfide. Herein, honeycomb-like mesoporous Co, N-doped carbon nanosheets (MC-NS) with a high specific surface area and abundant defects are developed which, simultaneously enable polysulfide confinement and highly efficient conversion. Moreover, density functional theory calculations and experime...

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Highly efficient and low‐cost electrodes have a key role in the development of advanced energy devices such as fuel cells and metal–air batteries. However, electrode performance is typically limited by low utilization of active sites, which causes a considerable drop in energy density. To overcome this issue, a single‐atom‐containing integrated electrode is developed through a confinement synthesis strategy by using organic molecule‐intercalated layered double hydroxides (LDHs) as precursors. The as‐prepared integrated electrode has a well‐defined nanosheet array structure with a homogeneous anchored single atomic Co catalyst and many exposed hierarchical pores. Moreover, the coordination environment of single atoms (CoN or CoS) is precisely controlled by regulating the type of interlayer molecules in the LDHs. Consequently, the optimized electrode exhibits high bifunctional activity toward both the oxygen reduction and oxygen evolution reactions. This electrode is directly assembled into an all‐solid‐state zinc–air battery that showed outstanding flexibility and long‐term charge/discharge stability. Because of the versatility of LDH materials, it is expected that the proposed strategy can be extended to the construction of other integrated electrodes for high‐performance energy storage and conversion devices.

Layered double hydroxides (LDHs), as a class of typical two‐dimensional materials, have sparked increasing interest in the field of energy storage and conversion. In the last few years, the research about LDHs as electrode active materials has seen much progress in terms of structure designing, material synthesis, properties tailoring, and applications. In this review, we focus on the integrated nanostructural electrodes (INEs) construction using LDH materials, including pristine LDH‐INEs, hybrid LDH‐INEs, and LDH derivative‐INEs, as well as the performance advantages and applications of LDH‐INEs. Moreover, in the final section, the insights about challenges and prospective in this promising research field were concluded, especially in regulation of intrinsic activity and uncovering of structure–activity relationship, which would push forward the development of this fast‐growing field.