The type-II CdO/CdS heterostructure is a promising visible light water-splitting photocatalyst.

Visible-light-driven photocatalytic overall water splitting is deemed to be an ideal way to generate clean and renewable energy. The direct Z-scheme photocatalytic systems, which can realize the effective separation of photoinduced carriers and possess outstanding redox ability, have attracted a huge amount of interest. In this work, we have studied the photocatalytic performance of the bilayer MoSe₂/HfS₂ van der Waals (vdW) heterojunction following the direct Z-scheme mechanism by employing the hybrid density functional theory. Our calculated results show that the HfS₂ and MoSe₂ single layers in this heterojunction are used for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The charge transfer between the two layers brought about an internal electric field pointing from the MoSe₂ layer to the HfS₂ slab, which can accelerate the separation of the photoinduced electron–hole pairs and support the Z-scheme electron migration near the interface. Excitingly, the optical absorption intensity of the MoSe₂/HfS₂ heterojunction is enhanced in the visible and infrared region. As a result, these results reveal that the MoSe₂/HfS₂ heterojunction is a promising direct Z-scheme photocatalyst for photocatalytic overall water splitting.

The search for 2D ferromagnets with versatile magneto-electronic properties is becoming more active due to their potential applications in spintronic devices. To screen out the optimal compositions, we have explored a series of two-dimensional M₃C₁₂X₁₂ (M = 5d transition metals, and X = S, NH, and O) metal–organic frameworks with Kagome lattice patterns through first-principles calculations. By varying the metal center and ligand functional radicals, both the electronic and spin-related properties can be easily tuned to meet the requirements for multifunctional applications in spintronic devices. Among them, Re₃C₁₂N₁₂H₁₂ is identified to be a ferromagnetic bipolar magnetic semiconductor with the highest Curie temperature (T_C > 330 K). Re₃C₁₂O₁₂ is found to be an ideal half-metal with a spin gap of 0.97 eV, which is beneficial for use as a spin-filter. Meanwhile, both Re₃C₁₂N₁₂H₁₂ and Re₃C₁₂O₁₂ exhibit considerable out-of-plane magnetic anisotropy energies (>26 meV per atom), which benefit the spintronic applications. The theoretical results not only show that the 2D organometallic Kagome lattice is a good platform for designing spintronic materials, but also provides a feasible way to realize robust spin manipulation.

Based on first-principles calculations, we propose for the first time that three different (0D, 1D, and 2D) TEs are simultaneously present in a synthetic compound, HfIr ₃ B ₄ , with a P 6 ₃ / m type structure.