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.

Polytetrafluoroethylene/Polyetheretherketone (PTFE/PEEK) corrosion-resistant coatings were prepared on the surface of 7075 aluminum alloy by the electrostatic powder spraying technique (EPST). To achieve a denser microstructure and improved hydrophobic properties, we introduced nano-CeO₂ to fill the coatings and analyzed the mechanism of its effect on the different coating structures. The corrosion resistance of the coatings was evaluated using NaCl immersion. The results indicate that nano-CeO₂ enhances the coatings by filling local defects and forming a denser microstructural barrier, thereby improving the hydrophobicity and corrosion resistance of the composite coatings. Additionally, the addition of nano-CeO₂ to the 20 µm PTFE/PEEK composite coating increases structural heterogeneity and pore defects, reduces coating densification, and facilitates the penetration of corrosive media, thereby weakening the barrier capability of the coating. However, in the 50 µm PTFE/PEEK/CeO₂ composite coating, nano-CeO₂ particles fill part of the pre-existing defects and improve coating densification, thereby increasing the resistance to the penetration of corrosive media through the coating. This enhanced barrier effect delays the contact of corrosive media with the substrate and improves the corrosion resistance of the coating. In this study, the 50 μm PTFE/PEEK/CeO₂ composite coating with a nano-CeO₂ content of 0.5 wt.% exhibited the best corrosion resistance, with a corrosion current density of 8.02 × 10⁻⁴ μA·cm⁻², while |Z|_0.01Hz remained above 10⁶ Ω·cm² after 720 h of immersion in NaCl solution.