NiCr/hBN self-lubricating composites with hBN solid-lubricant contents of 8%, 9%, 10%, 11%, and 12% (mass fractions) were prepared by powder-metallurgy method. Their tribological properties at room temperature and 600, 700, and 800 °C were studied. SEM and XRD were performed to analyze their wear-surface morphology and abrasive-dust composition. Results indicate that the NiCr/hBN self-lubricating composites have favorable tribological properties at room temperature and 600 °C. The optimum comprehensive friction and wear performance are achieved at 10% hBN, and the main wear mechanism is abrasive wear. At 700 and 800 °C, the friction and wear properties of NiCr/hBN self-lubricating composites obviously decline. The wear surface experiences oxidation and the spinel oxides Cr2O3, NiCr2O4, and CrBO3 are formed. The main wear mechanism becomes combined scratching and glue form of adhesive wear, leading to greatly increased wear rate for the NiCr/hBN sel-lubricating composites.

Tungsten carbide (WC) is an alternative to the costly and resource-constrained Pt-based catalysts for hydrogen evolution reaction (HER). In this work, a one-step facile and easily scalable approach is reported, to synthesize ultrafine WC by molten salt. Benefiting from the ideal synergistic catalytic effect between the highly active WC nanoparticles and the conductive graphitic carbon, and strong charge transfer ability, the unique WC/C hybrids demonstrated excellent HER performance in both acid and alkaline medias with overpotentials of 112 and 122 mV, at a current density of 10 mA cm⁻² and Tafel slopes of 54.4 and 68.8 mV dec⁻¹, in acid and alkaline media, and remarkable stability. With the simplicity and low-cost of the synthetic approach, the strategy presented here can be extendable to the preparation of other transition metal-based/carbon hybrids for versatile applications.

Plating bath composition, temperature, current density, and pH have a great influence on the properties of a Co-Mo alloy coating. However, these conclusions are obtained from the perspective of test results. Most of the factors that affect the properties of the coating operate by interfering with the electrodeposition process. Therefore, it is of great significance to study the kinetics of the electrodeposition process. To further study the influence of process parameters on the deposition process of Co-Mo alloy coatings, cyclic voltammetry (CV), scanning linear voltammetry (LSV), and electrochemical impedance testing (EIS) were used to study the deposition kinetics of Co-Mo alloy coatings. The results show that with the increase in sodium molybdate content in the plating solution, more Mo elements are involved in the deposition process. At the same time, a higher Mo element content can reduce the dissolution of the coating as the anode and improve the service life of the coating, but too high a Mo element content will lead to cracks on the surface of the coating. The deposition temperature will affect the processes of reduction deposition and oxidation dissolution of the coating. The pH of the plating bath will directly affect the reduction reaction process of MoO₄²⁻ ions in the plating bath. With the increase in the pH value, the reduction reaction rate of MoO₄²⁻ ions decreases, and the cathodic reduction reaction current density decreases. At the same time, the peak current density of anodizing decreases with the decrease in the pH value of the plating solution, indicating that the alkaline plating solution has an inhibitory effect on the plating dissolution process.

In the “dual carbon” objective, the preparation of non-precious metal catalysts with low cost and high activity is essential for the study of hydrogen evolution reactions (HERs). This study employed biomass pomelo peel powder as the carbon source and ammonium metatungstate (AMT) as the tungsten source and, through a facile one-step method in molten salt, fabricated a biomass carbon-based nanocatalyst featuring carbon flakes adorned with tungsten carbide (WC) nanoparticles. Dicyandiamide and cysteine were introduced as nitrogen and sulfur sources, respectively, to explore the impacts of N-S elemental doping on the structure, composition, and HER performance of the WC/C catalyst. The experimental results showed that N-S doping changed the electronic structure of WC and increased the electrochemically active surface area, resulting in a significant increase in the HER activity of WC/C@N-S catalysts. The WC/C@N-S catalyst was evaluated with hydrogen evolution performance in a 0.5 mol/L H₂SO₄ solution. When the cathodic current density reached 10 mA/cm², the overpotential was 158 mV, and the Tafel slope was 68 mV/dec, underscoring its excellent HER performance. The outcomes offer novel insights into the high-value utilization of agricultural biomass resources, and pave the way for the development of cost-effective, innovative hydrogen evolution catalysts.