Hubei University of Science & Technology

Photocatalytic water splitting (PWS) for hydrogen production is a crucial strategy to address the energy crisis and environmental pollution. In this study, we investigated the stability, electronic structure, and PWS performance of three 2D materials, SiAs, GeAs, and SnAs, using first-principles calculations. Our results reveal that all three monolayers exhibit high stability, with heat resistance up to 1000 K. They are indirect bandgap semiconductors, with band gaps ranging from 1.64 eV to 2.59 eV, and electron mobilities between 142.18 and 366.18 cm²/Vs. Besides, these monolayers also possess suitable band edges, with valence band maximum below -5.67 eV and conduction band minimum above -4.44 eV, making them as candidates for PWS applications. Furthermore, they release strong light absorption, reaching ∼10⁵ cm^-1, with GeAs and SnAs covering the range from visible to ultraviolet regions. Additionally, they have low exciton binding energies (210-410 meV) and high solar-to‑hydrogen efficiencies (6-17 %). In conclusion, the three monolayers demonstrate significant potential for applications in nanoelectronics and PWS technologies.

The development of cost-effective, high-efficiency oxygen evolution reaction (OER) catalysts through precise compositional and structural design via guest doping engineering represents a significant research challenge. While cobalt silicate (CoSi) has emerged as a promising OER catalyst, its practical application has been limited by relatively high overpotential (η). In this study, we presented a strategic Fe-doping approach to engineer the electronic structure of CoSi, significantly enhancing its OER performance. Through hydrothermal synthesis, we successfully incorporated Fe atoms into the CoSi framework, creating hollow spherical iron-doped cobalt silicate (CoSi-Fe) catalysts. Comprehensive characterization revealed that the geometric and synergistic effects of Fe-doping facilitate: (1) increased exposure of active sites, (2) enhanced activity of Co/Fe dual sites, and (3) improved structural stability of Co species. Density functional theory (DFT) calculations further demonstrated that Fe incorporation optimizes reaction kinetics and improves electrical conductivity, collectively boosting OER activity. The optimized CoSi-Fe-3 catalyst (Co/Fe = 15:5) exhibits exceptional performance, achieving an overpotential of only 289 mV at 10 mA cm^-2 (a 118 mV reduction compared to pristine CoSi of 407 mV) and superior to most reported metal silicate catalysts. We systematically analyzed the structure-activity relationship underlying this performance enhancement. This work establishes an effective doping strategy for developing high-performance silicate-based electrocatalysts, providing valuable insights for advancing renewable energy conversion technologies.

Considering the large-scale production of lithium-ion battery anode materials, the advantages of silicon-based anodes would be overshadowed if both performance and cost were not properly optimized. However, current preparation methods for silicon‑carbon anodes face challenges such as low efficiency and high energy consumption, limiting the sustainable commercialization. This work proposes a novel, cost-effective method for fabricating silicon‑carbon anodes by utilizing a hydrogen bond network in combination with multiple chemical bonds. Through a one-step hydrothermal method, silicon nanoparticles, nickel foam, and a Ni-doped hydrochar-based amorphous carbon network are assembled into the integrated NF-Si@GC electrode. The calculation demonstrates that multiple chemical bonds between each component in composite structure introduces a built-in electric field across the three materials, which generates a driving force for electron transfer on the surface of Si. As expected, the NF-Si@GC electrode exhibits a high reversible charge capacity of 1454 mAh g^-1 at 0.1 A g^-1, maintains 970 mAh g^-1 at a high areal loading of 1.41 mg cm^-2, and achieves one of the lowest preparation costs for common silicon anodes reported to date. The study of this reaction mechanism provides inspiration for the large-scale production of other battery materials and the scalable manufacturing of high-performance electrodes.