Silicon carbide (SiC) has emerged as a robust and tunable semiconductor for advanced photocatalytic applications. This review provides a comprehensive overview of recent progress in the development of SiC-based materials for environmental remediation and solar-driven hydrogen production. Key aspects discussed include morphological engineering, heterostructure design, doping strategies, and plasmonic enhancement. Emphasis is placed on structure–activity relationships, insights from density functional theory (DFT) and machine learning (ML) models, and synergistic effects in composite systems. This review concludes with a critical analysis of current challenges and future research directions, highlighting the potential of SiC implementation as a sustainable platform for next-generation photocatalytic technologies.

Silicon carbide (SiC) has attracted increasing attention as a robust photoelectrode material for solar water splitting due to its exceptional chemical stability, mechanical strength, and resistance to photocorrosion. Recent advances in nanostructuring—particularly the development of nanoporous SiC architectures—have dramatically improved light absorption, charge separation, and charge transport in this material. This review summarizes current strategies to enhance the PEC performance of SiC, including hierarchical nanostructuring, defect engineering (e.g., doping to tailor band structure), heterojunction formation with co-catalysts, and incorporation of plasmonic nanoparticles. Remaining challenges are discussed, notably the wide band gap of common SiC polytypes (limiting visible-light utilization) and rapid charge-carrier recombination. In addition, we examine the techno-economic prospects for SiC-based PEC systems, outlining the efficiency and durability benchmarks required for commercial hydrogen production. Finally, we propose future research directions to achieve efficient, durable SiC photoelectrodes and to guide the development of scalable PEC water-splitting devices. This review uniquely integrates material design strategies with techno-economic evaluation, providing a roadmap for SiC-based PEC systems.

A combined CALPHAD-guided thermodynamic and experimental approach was employed to investigate the influence of boron on phase evolution and microstructural development in the Fe–Ni–Cr–Cu–Si–B–C alloy system. Thermodynamic calculations were performed using Thermo-Calc (FE13-2025b) and the TTFe thermodynamic database. Vertical phase-diagram sections and response surface analysis were used to evaluate phase stability over the temperature range of 400–1500 °C and to identify temperature–composition domains favorable for the formation of strengthening phases. The calculations predicted complex multiphase equilibrium behavior involving boride-, carbide-, and silicide-containing phases. Within the investigated composition range, approximately 4 wt.% B provided a favorable balance between the metallic matrix and strengthening phases, while 638 °C corresponded to a thermodynamically favorable equilibrium phase constitution. Response surface analysis further demonstrated that temperature governs phase evolution, whereas boron primarily controls phase redistribution. The optimized alloy composition was characterized experimentally using scanning electron microscopy (SEM), wavelength dispersion spectroscopy (WDS), elemental mapping, and X-ray diffraction (XRD). The experimentally observed heterogeneous multiphase microstructure showed good agreement with the CALPHAD-predicted phase evolution at a qualitative level, demonstrating the usefulness of thermodynamic modeling for guiding alloy design. The proposed CALPHAD-guided workflow integrates thermodynamic modeling with targeted experimental characterization and provides a transferable framework for the accelerated design and optimization of complex Fe-based multicomponent alloys.

This study applies a depth-based description of indentation response to AISI 321 stainless steel and a detonation-sprayed FeNiCoMoW coating. Martens hardness H_M was evaluated from the maximum indentation depth, while a residual-depth-based quantity H_pl was calculated using the retained depth. The corresponding hardness ratio H_pl/H_M was examined in relation to the retained-depth fraction. Instrumented Vickers indentation was performed on untreated AISI 321 stainless steel and the FeNiCoMoW coating. Maximum and residual indentation depths were obtained from load–displacement curves. Coating morphology was examined by optical microscopy and phase composition by X-ray diffraction. The FeNiCoMoW coating formed a continuous layer with a 145 ± 8 μm thickness. Compared with the substrate, the coating reduced the retained-depth fraction from 0.906 to 0.788 and increased the hardness ratio from 1.22 to 1.61. Indentation hardness increased from 2.3 ± 0.17 GPa for the substrate to 8.65 ± 1 GPa for the coating. X-ray diffraction identified the (Mo,W)₂C carbide crystalline phase together with an fcc (Co,Ni,Fe) solid solution and σ- and μ-type intermetallic compounds. The proposed descriptors provide a compact characterization of indentation response and distinguish retained-depth behavior from conventional contact-depth-based hardness measurements. For the investigated coating, the lower retained-depth fraction and higher hardness indicate a greater recovered-depth contribution during unloading.