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Exploring inexpensive and earth-abundant electrocatalysts for hydrogen evolution reactions is crucial in electrochemical sustainable chemistry field. In this work, a high-efficiency and inexpensive non-noble metal catalysts as alternatives to hydrogen evolution reaction (HER) was designed by one-step hydrothermal and two-step electrodeposition method. The as-prepared catalyst is composed of the synergistic MoS2–Co3S4 layer decorated by ZnCo layered double hydroxides (ZnCo-LDH), which forms a multi-layer heterostructure (ZnCo/MoS2–Co3S4/NF). The synthesized ZnCo/MoS2–Co3S4/NF exhibits a small overpotential of 31 mV and a low Tafel plot of 53.13 mV dec−1 at a current density of 10 mA cm−2, which is close to the HER performance of the overpotential (26 mV) of Pt/C/NF. The synthesized ZnCo/MoS2–Co3S4/NF also has good stability in alkaline solution. The excellent electrochemical performance of ZnCo/MoS2–Co3S4/NF electrode originates from its abundant active sites and good electronic conductivity brought by the multilayer heterostructure. This work provides a simple and feasible way to design alkaline HER electrocatalysts by growing heterostructures on macroscopic substrates.

Rational design of composite materials with unique core-shell nanoflower structures is an important strategy for improving the electrochemical properties of supercapacitors such as capacitance and cycle stability. Herein, a two-step electrodeposition technique is used to orderly synthesize CuCo2O4 and CoS on Ni foam coated with Cu/Co bimetal metal organic framework (Cu/Co-MOF) to fabricate a hierarchical core-shell nanoflower material (CuCo2O4@CoS-Cu/Co-MOF). This unique structure can increase the electrochemically active site of the composite, promoting the Faradaic redox reaction and enhancing its electrochemical properties. CuCo2O4@CoS-Cu/Co-MOF shows a prominent specific capacitance of 3150 F g−1 at 1 A g−1, marvelous rate performance of 81.82% (2577.3 F g−1 at 30 A g−1) and long cycle life (maintaining 96.74% after 10,000 cycles). What is more, the assembled CuCo2O4@CoS-Cu/Co-MOF//CNTs device has an energy density of 73.19 Wh kg−1 when the power density is 849.94 W kg−1. It has unexpected application prospects.

Platinum group compounds are currently the best performance hydrogen evolution catalysts, but their high price and low abundance limit their large-scale applications. Therefore, noble-metal-free catalysts have become a focus in the research of hydrogen evolution reactions (HER). In this work, we developed a noble-metal-free HER catalyst consisting of Co3O4 supported on N-doped carbon nanotubes (Co3O4-NCTs). The Co3O4-NCT catalyst synthesized by stirring, heating, and high-temperature calcination was studied, showing a very low Tafel plot (32.3 mV dec−1) in an alkaline solution and good stability for hydrogen evolution reactions. In addition, the material synthesis method is simple, the experimental raw materials are cheap and easy to obtain, and it is expected to be suitable for large-scale industrial production.

The design and development of composite materials with novel structures is one of the effective ways to enhance the electrochemical properties of supercapacitors. In this paper, a one-step electrodeposition method is used to adjust the morphology and structure of CoMnS nanomaterials by changing the amount of CS2. CoMnS nanomaterials with unique flower-like structures are reasonably prepared, which promotes the flow of electron transfer and improves the electrochemical behavior. It is worth noting that when the amount of CS2 is 4 mmol, the specific capacitance of CoMnS-4 reaches 3469.5 F g−1 at 1 A g−1, and the specific capacitance is still 2830.5 F g−1 (maintaining 81.56%) until the high current density reaches 20 A g−1. After 10 000 cycles, it shows excellent cycle stability (maintaining 95.78% at 20 A g−1). The CoMnS-4//AC asymmetric supercapacitor device has an excellent energy density of 85.91 W h kg−1 when the power density is 800 W kg−1, which shows it's great application value.

The synergistic effect of Ce[Formula: see text] and SiO2 nanoparticles (NPs) composite silane film on the corrosion resistance of carbon steel was researched. The preparation method of silane film is mainly hydrolysis of bis-1,2-(triethoxysilyl)ethane (BTSE) and 3-glycidoxypropyltrimethoxysilane (KH-560) under acidic conditions and condensation reaction. EDX and SEM were employed to analyze the element distribution and morphological characteristics of the coating, which confirmed the coatings were crack-free and even distribution of surface elements. The chemical bond structure characteristics of the silane film on carbon steel were analyzed by XPS, and compared with the silane film after ultrasound. It proved the bonding force of the silane film. The best corrosion current density of the silane film containing cerium is 4.65 [Formula: see text]Acm[Formula: see text]. The [Formula: see text] obtained by simulating the corrosion circuit through Zsimpwin software is 22.02[Formula: see text]k[Formula: see text]cm[Formula: see text]. On this basis, by adding different concentrations of SiO2 NPs, the corrosion current density can reach a minimum of 0.70 [Formula: see text]Acm[Formula: see text]. The simulated polarization curve [Formula: see text] was 65.13[Formula: see text]k[Formula: see text]cm[Formula: see text]. In the long-term open-circuit potential test, the potential of the silane film containing rare earth cerium increased to 38[Formula: see text]mV at a certain stage, which proves the self-healing performance of the film.

Hydrogen energy has become one of the most potential sources for replacing fossil fuels due to its environmental friendliness and high energy conversion rate. Electrolyzed water is a hydrogen evolution process with high efficiency, no by-products, and high hydrogen purity. Here, we propose to use ZIF-67 as the precursor to prepare three-dimensional multilayer rGO supported CoS2 quantum dots (CoS2QDs@rGO) through a two-step hydrothermal method and one-step calcinations method. The as-prepared electrocatalyst with maximum exposure of edge active sites is highly efficient for hydrogen evolution reaction (HER), delivering an extremely small Tafel slope of 78 mV dec-1, and prominent durability. Density functional theory (DFT) calculations reveal that decoration of CoS2QDs not only obviously changes Gibbs free energy of hydrogen adsorption (ΔGH*), but also offers more active sites for HER, conspicuous promoting the catalytic activity of as-obtained electrode materials. It can be expected that our CoS2 quantum dots mounted on three-dimensional multilayer rGO with ZIF-67 as the precursor, will provide a novel, high-yield and effective catalytic material for energy conversion applications.

Reasonable assembly and heterogeneous growth using new energy storage materials is a popular and promising method to ameliorate the electrochemical performance of hybrid supercapacitors. Herein, a unique intercalation pseudocapacitance characteristics and battery-type electrode materials layered double hydroxides (LDHs) nanosheet arrays are obtained by a simple and environmentally pollution-free two-step electrodeposition technology. The electrode materials are composed of MoO3 and NiCo-layered double hydroxides (NiCo-LDH), which was directly grown on the three-dimensional (3D) conductive nickel foam (NF) substrate, forming a binder free two-dimensional (2D) ultra-thin cross-multilayer heterostructure (NiCo-LDH@MoO3/NF). The heterogeneous NiCo-LDH@MoO3/NF nanomaterial manifests a prominent specific capacity of 952.2 C g−1 at the current density of 1 A g−1, and also delivers good cycling performance of 86.42% capacity retention at current density of 20 A g−1 after 10,000 cycles. Remarkably, the fabricated NiCo-LDH@MoO3/NF//AC HSC equipment shows an excellent energy density, whose value is 58.06 Wh kg−1 with the power density of 800 W kg−1, and the capacity retention rate and coulombic efficiency can reach 73% and 96.7% at 15 A g−1, respectively, suggesting that it has application prospects in supercapacitor electrode materials.

The development of asymmetric supercapacitors with good cycle stability and high energy density is becoming increasingly a research focus of energy storage systems. Herein, this work has reported a novel method to prepare CuCo2S4/Co-MOF (metal-organic framework) electrode materials. The electrochemical properties of materials are studied by changing the electrodeposition temperature. CuCo2S4-45, CuCo2S4/Co-MOF obtained at an electrodeposition temperature of 45 °C, has a microstructure of a multi-layer sheet-like two-dimensional ultra-thin honeycomb, which can shorten the diffusion path between ions/electrons. In addition, the specific capacitance of CuCo2S4-45 can reach 2879 F g−1 at 1 A g−1 as well as the capacity retention rate is 80.3% (2312 F g−1 at 20 A g−1). Asymmetric supercapacitor CuCo2S4-45//AC using activated carbon (AC) has excellent cycle stability (maintains 82.02% after 10,000 cycles), the energy density of 63.6 W h kg−1 at power density of 700 W kg−1. The results show that the material has great practical value.