methods to suppress the release of CO 2 , using photo-or electrocatalysis. [7-10] Particularly, the electrocatalytic reduction can be a promising method for managing the global carbon balance and issues regarding energy generation, as it can convert CO 2 to C1 or C2 chemical products as fuel. [11,12] However, this reduction process faces significant challenges due to the chemical inertness of CO 2 , as there are high thermodynamic and kinetic barriers to obtain a successful electrocatalytic reduction of CO 2. Additionally, the CO 2-to-CO pathway is usually selected, because CO is the raw material of the Fisher-Tropsch process and other added-value hydrocarbons with wide distribution (C1-C3 products). [13-17] On the other hand, the competing hydrogen evolution reaction (HER) and the stable CO bond of CO 2 can optimize the catalytic system through the activity and selectivity during the CO 2-to-CO electrocatalytic process. [18-21] Metal-and nitrogen-coordinated materials dispersed on carbon matrix (M-N x-C), with a high density of active sites, have attracted increased interests in the field of electrocatalytic reduction of CO 2 , due to their low cost and high abundance of raw material. [22-28] Nitrogen coordinated metal as catalytic sites that could be designable to fit the especial functionality. As is already known, the Cu-N x-C sites can have much more interaction with the oxygen of the CO 2 , which can enhance the enthalpy of the CO 2 and inhibit the HER but results in sluggish kinetics of the CO 2 + H + + e − → COOH* process. [29,30] Besides, the Fe-N x-C materials are often applied in CO 2 reduction with low onset potential. Nevertheless, the desorption of *CO into the gas phase can reduce the reactivity, due to the strong binding of CO to the Fe-N x-C sites in the step of COOH* + H + + e − → CO* + H 2 O and CO* → CO+ *. [31-33] Considering the issues mentioned above, to maximize the potential of single-atom catalysts for multistep catalytic reaction, we design and synthesize biatomic active sites of Cu-Fe-N 6-C catalyst by pyrolysis of PcCu-Fe-ZIF-8 under an argon atmosphere at 1000 °C (the detail can be found in the Supporting Information). The configuration and coordination environment of the diatomic catalyst are evidenced by the aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (STEM) (AC HAADF-STEM) and X-ray adsorption spectroscopy. The experimental results show To relieve the green gas emission and involve the carbon neutral cycle, electrochemical reduction of CO 2 attracts more and more attention. Herein, a biatomic site catalyst of Cu-Fe coordinated with the nitrogen, which is doped in the carbon matrix (denoted as Cu-Fe-N 6-C), is designed. The as-obtained Cu-Fe-N 6-C exhibits higher performance than that of Cu-N-C and Fe-N-C, owing to bimetallic sites, proving synergistic functions based on different molecules and their interfaces. Cu-Fe-N 6-C shows high selectivity toward CO, with high Faradaic efficiency (98% at −0.7 V), and maintaining 98% of its in...

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In the area of catalysis, selective reduction of nitro compounds to amino compounds is a colossal challenge due to the existence of competitive reducible functional groups. Herein, an Fe-based catalyst FeSAs/Fe2O3ACs/N-doped polyhedral carbon (NPC) has been designed and synthesized. As we expected, compared with FeSAs and FeNPs, FeSAs/Fe2O3ACs/NPC shows excellent catalytic performance (turnover frequency up to 1923 h–1, calculated with nitrobenzene), chemoselectivity, and tolerance during the hydrogenation reaction of nitro compounds under room temperature because of the synergistic effects between FeSAs and Fe2O3ACs. The theoretical calculations show that FeSAs prefers to undergo hydrazine decomposition to generate hydrogen and the Fe2O3ACs surface is more active toward the nitrobenzene reduction to aniline.

By virtue of the prominent features of low cost, high surface area, wide potential window, high theoretical capacity and rich valence states, manganese (Mn)-based materials and their composites have attracted...

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utilization of environmentally friendly renewable energy sources, such as solar energy, wind energy, and tidal energy. However, these renewable energy sources are intermittent in nature, which makes them unable to provide a stable energy supply. Therefore, energy storage devices play an integral role in setting up renewable energy systems. [1] At present, electrochemical energy storage (EES) technologies are the most commonly used due to high energy conversion efficiency, wide range of energy and power densities, relatively long lifetime, and low maintenance costs, among which lithium-ion batteries (LIBs) and supercapacitors (SCs) are considered to be the promising two. [2,3] LIBs, which have occupied half of the market of EES devices since their successful commercialization more than 30 years ago, have the advantages of high energy density, stable performance, and moderate cost, but their low power density and poor cycle performance are detrimental to fast and longterm energy storage. [4][5][6] By contrast, SCs, another excellent energy storage device, have the ability to store and release energy quickly and has an extremely long cycle life and good safety. The very limited energy density however greatly increases the number of equipment required to store the same energy, thus making SCs undesirable to meet the actual demand for high energy storage. [7][8][9] Consequently, in order to assist in realizing the vision of replacing nonrenewable fossil energy with environmentally friendly renewable energy, EES devices that can concurrently provide good energy density and high power performance are urgently needed.As a new type of EES device emerging after metal-ion batteries (MIBs) and SCs, metal-ion hybrid capacitors (MHCs) blessed with fabulous power performance, decent energy density, and remarkable cycle stability are considered to be one of the most prospective EES devices. [10] In 2001, the first MHC, using activated carbon (AC) as the cathode and nanostructured Li 4 Ti 5 O 12 (LTO) as the anode, was constructed by Amatucci et al., which possessed an energy density as high as 20 Wh kg −1 , about threefold than that of traditional SCs, showing promising rate capability in the meanwhile. [11] ThisThe design and development of advanced energy storage devices with good energy/power densities and remarkable cycle life has long been a research hotspot. Metal-ion hybrid capacitors (MHCs) are considered as emerging and highly prospective candidates deriving from the integrated merits of metal-ion batteries with high energy density and supercapacitors with excellent power output and cycling stability. The realization of high-performance MHCs needs to conquer the inevitable imbalance in reaction kinetics between anode and cathode with different energy storage mechanisms. Featured by large specific surface area, short ion diffusion distance, ameliorated in-plane charge transport kinetics, and tunable surface and/or interlayer structures, 2D nanomaterials provide a promising platform for manufacturing battery-type electrod...