There is an urgent need to improve the corrosion resistance of WC-based cermet coatings in different corrosive environments. The main objective of this work was to investigate the microstructure and evaluate the corrosion resistance in neutral, acidic, and alkaline electrolytes of the WC-based cermet/Fe-based amorphous alloy composite coating. Thus, a composite coating of WC–CoCr/Fe-based amorphous alloy and a single WC–CoCr coating were fabricated using the high-velocity oxygen fuel (HVOF) process. The phase composition, microstructure of the original powders, and as-sprayed coatings were studied. The detailed interface information between different compositions of the composite coating was observed by high-resolution transmission electron microscopy (HRTEM). The corrosion resistance of the coatings was studied comparatively by electrochemical tests in 3.5 wt % NaCl, 1 M HCl and 1 M NaOH solutions, respectively. Results showed that the composited coating had a dense layered structure with a composition of WC, Fe-based amorphous alloy, and small amount of W₂C. It was revealed that obvious inter-diffusion exists between the interfaces of tungsten carbide/Co, Cr binder and WC–CoCr/Fe-based amorphous alloy. The electrochemical test results showed that the composite coating displayed better corrosion resistance than single WC–CoCr coating both in 3.5 wt % NaCl solution and in 1 M NaOH solution.

The specific surface area, porosity, and mechanical properties of a catalyst are critical factors that significantly influence its performance. However, conventional preparation techniques are incapable of optimizing these properties simultaneously. Here, we present the performance of three kinds of catalysts with different geometric structures. Our findings indicated that the porosity, specific surface area, and mechanical properties of the 3D-printed catalysts achieved an optimal balance, exhibiting enhanced catalytic efficiency and mechanical integrity compared to commercial catalysts. Furthermore, the excellent ductility of the metal catalyst supports effectively prevented catalyst pulverization caused by carbon deposition and the thermal expansion of the supports. These results demonstrate that 3D printing technology can open up novel avenues for catalyst preparation, especially for metal-supported catalysts. The potential of metal additive manufacturing in chemical engineering is substantial, promising transformative advancements in the design and fabrication of catalytic converters and reactors.

Hydrogen is an ideal feedstock fuel for solid oxide fuel cells (SOFCs). The steam reforming of methane (SRM) is the predominant method of producing hydrogen. However, the process of SRM relies on the involvement of a catalyst, and the reforming efficiency is constrained by the limited surface area in the traditional catalyst system. In this study, a mixer structure is applied to improve the mixing of the methane. Nano-sized pores are introduced to the struts of the mixer structure, forming a hierarchical structure, to effectively reduce the weight and increase the surface area of the self-catalytic reactors, hence increasing the catalytic efficiency. The hierarchical structure increases the reforming efficiency at all temperatures, and the level of improvement reaches its peak when the conversion rate of methane increases by 192% at 800 °C and by 40% at 900 °C compared to the self-catalyst without a hierarchical structure.