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The synthesis of multi‐carbon products through electrochemical CO2 reduction reactions has attracted great interest from researchers. Herein, nitrogen‐ and carbon‐doped copper nanocatalyst (NC−Cu) containing abundant Cu−N−C active sites was prepared by thermal decomposition of the complexes containing copper and melamine. The NC−Cu catalyst exhibited an ideal current density of 22 mA cm−2 at −0.93 V versus reversible hydrogen electrode (vs. RHE) in CO2‐saturated 0.5 M KHCO3 medium, with ethanol as the predominant product at −0.93 V (vs. RHE) and a maximum Faraday efficiency of 31 %. The current density of the catalyst remained almost unchanged after 20 h of electrolysis, indicating its excellent stability. The excellent catalytic ability is attributed to the abundant Cu−N−C active sites of NC−Cu with 3D porous microstructure. [ABSTRACT FROM AUTHOR]

Long-cycle stability and high-energy density are big challenges for developing high-performance hybrid supercapacitor (HSC) electrode materials. In this work, molybdenum-doped Co3O4 nanosheets arrays on nickel foam (noted as MoxCo1.5−xO/NF) are successfully prepared via facile one-step electrodeposition followed by annealing for hybrid supercapacitors. The experimental and calculated results indicate that the band gap modification and conductivity enhancement of MoxCo1.5−xO lead to excellent capacitive performance due to the doping of Mo into Co3O4. The as-prepared Mo0.25Co1.25/NF electrode demonstrates a high specific capacity of 128.2 mAh g−1 (923 F g−1) at 1 A g−1 (60% higher than the undoped Co3O4) and superior cycle stability with 95.2% capacity retention after 10,000 cycles at 10 A g−1. The assembled HSC delivers high-energy density of 64.3 Wh kg−1 at the power density of 794.1 W kg−1 and with 87.7% capacity retention after 10,000 cycles. This work can present a new strategy to fabricate the three-dimensional high-performance integrated electrode materials by a facile electrodeposition for heteroatom-doped transition metal oxide for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Ammonia borane (NH3BH3, AB), a carbon-free-energy material, has attracted enormous attention not only as the hydrogen storage source but also as the anodic fuel for direct AB fuel cells (DABFCs). The rational design of electrocatalysts for AB oxidation reaction (ABOR) is the key to improve the electrochemical performance of DABFCs. Herein, copper-doped nickel metaphosphates (Cu–Ni(PO3)2) with modulated electronic structure and abundant lattice defects through tuning dopant ratios are synthesized and applied towards ABOR for the first time. The optimal Cu–Ni(PO3)2 catalyst shows excellent electrocatalytic performance with an onset potential of −0.282 V versus the reversible hydrogen electrode (vs. RHE) which is superior to the published noble-metal and other transition metal electrocatalysts. And the density functional theory (DFT) computations verified that the active sites in the Cu–Ni(PO3)2 towards ABOR are the dopant Cu ions, the optimized Ni ions, and the induced lattice distortions, which indicates that the doping of Cu ions can indeed improve the electrocatalytic activity of the host catalyst Ni(PO3)2. This work provides a new candidate for the electrocatalyst of ABOR. [ABSTRACT FROM AUTHOR]

Nb2O5@carbon/reduced graphene oxide (M-Nb2O5@C/rGO) composites are fabricated by annealing the precursor of graphene oxide supported Nb-based metal organic frameworks for the first time. The lithium ion capacitor using M-Nb2O5@C/rGO as the anode and activated carbon as the cathode delivers a high energy density of 71.5 W h kg−1 and excellent cycling stability. [ABSTRACT FROM AUTHOR]

Amorphous materials disrupt the intrinsic linear scalar dependence seen in their crystalline counterparts, typically exhibiting enhanced catalytic characteristics. Nevertheless, substantial obstacles remain in terms of boosting their stability, enhancing their conductivity, and elucidating distinct catalytic mechanisms. Herein, a core-shell catalyst, comprising a crystalline SnO 2 core and an amorphous SnO x shell supported on MXene (denoted as SnO 2 @SnO x /MXene), was prepared utilizing hydrothermal and solution reduction methods. The SnO 2 @SnO x /MXene catalyst excels in the electrocatalytic conversion of CO 2 to formate, yielding a Faradaic efficiency (FE) as high as 93% for formate production at -1.17 V vs RHE and demonstrating exceptional durability. Both density functional theory (DFT) calculations and experimental results indicate that the SnO x shell bolsters formate formation by fine-tuning the adsorption energy of the *OCHO intermediate. In SnO 2 @SnO x /MXene, MXene plays a vital role in enhancing the conductivity and stability of the amorphous shell and especially amplifying Raman signals of catalyst components. The ex/in situ surface-enhanced Raman scattering (SERS) application further confirms the formation of amorphous SnO x and further enables the direct detection of the formation of the intermediate species. This work provides the basis for the application of amorphous materials in practical electrocatalytic reduction of CO 2 reduction.

CuCo 2 O 4 , a type of promising lithium-ion storage material, exhibits high electrochemical properties in lithium-ion batteries and enormous economic benefits. However, its practical application is limited by problems such as structural collapse and electrochemical stability during the charging and discharging process. In this work, the reduced graphene oxide (rGO)-coated CuCo 2 O 4 (CuCo 2 O 4 /rGO) hollow microspheres were successfully prepared by electrostatic self-assembly. The CuCo 2 O 4 /rGO electrode shows an outstanding capability for lithium-ion storage and a remarkable rate capacity, e.g., 445 mA h g -1 at 5 A g -1 . After 150 cycles at 0.1 A g -1 , the reversible capacity of the CuCo 2 O 4 /rGO electrode is as high as 1080 mA h g -1 , and it can still retain about 530 mA h g -1 in the 400th cycle at 1 A g -1 . The hollow microspheres with mesoporous shells can cause electrolyte penetration into the spherical shell to effectively shorten the transfer distance of lithium ions, and the encapsulation of graphene improves the conductivity and stability of CuCo 2 O 4 , which endows CuCo 2 O 4 /rGO with a wonderful Li + storage performance. It is proved that this is an efficient method to improve the electrochemical performance of metal compounds for better applications in energy storage.

CoSnO 3 , as a high theoretical capacity electrode material (1235 mAh g -1 ) for lithium storage, has been limited due to its low rate performance, huge volume expansion, and an unstable solid electrolyte interface (SEI). A rational design of the material structure including carbon coating can effectively solve the problems. To buffer the volume change and achieve a superior rate capability, hollow CoSnO x nanocubes encapsulated in 1D N-doped carbon nanofibers (CNFs) were fabricated by electrospinning, showing a final discharge capacity of 733 mAh g -1 with a 96% capacity retention after 800 cycles at a current rate of 1 A g -1 and a brilliant rate performance (49% capacity maintenance with the current variation from 0.1 to 5 A g -1 ). Absolutely, these outstanding characteristics are ascribed to the unique structure. The N-doped carbon fibers outside not only prevent the volume expansion during Li + intercalation/extraction but also improve the electron transport in the electrode. Most significantly, the hollow structure offers enough vacant space to buffer the internal strain, while the porous structure shortens the Li + diffusion distance. Combined with electrospinning technology, this study shares a novel idea for designing various composites with rational structures and outstanding electrochemical properties.

Nb2O5@carbon/reduced graphene oxide (M-Nb2O5@C/rGO) composites are fabricated by annealing the precursor of graphene oxide supported Nb-based metal organic frameworks for the first time. The lithium ion capacitor using M-Nb2O5@C/rGO as the anode and activated carbon as the cathode delivers a high energy density of 71.5 W h kg-1 and excellent cycling stability.