The predicted type-II band alignment and the interfacial polarized field in g-C₃N₄/MoS₂ nanocomposite are responsible for its enhanced photocatalysis.

We report combined first-principle and tight-binding (TB) calculations to simulate the effects of chemical edge modifications on structural and electronic properties. The C-C bond lengths and bond angles near the graphene nanoribbon (GNR) edge have considerable changes when edge carbon atoms are bounded to different atoms. By introducing a phenomenological hopping parameter $t_1$ for nearest-neighbor hopping to represent various chemical edge modifications, we investigated the electronic structural changes of nanoribbons with different widths based on the tight-binding scheme. Theoretical results show that addends can change the band structures of armchair GNRs and even result in observable metal-to-insulator transition.

Metal oxide semiconductors with surface homojunctions characteristic of continuous band bending and well-defined epitaxial interfaces show amazing potential for photocatalytic applications. Herein, a new concept of facet junctions is proposed and validated according to the synergy between the co-exposed crystal facets of shape-tailored anatase TiO₂ single crystals. By considering the atomic and electronic interactions between the co-exposed facets, our density functional theory calculations reveal the existence of type-II band alignment between the co-exposed {001} and {101} facets. This band alignment results in in situ construction of a facet junction to allow built-in facet-mediated carrier transfer. The self-constructed {101}/{001} facet junction, due to the effective carrier separation between different exposed facets, exhibits a significantly enhanced quantum efficiency and catalytic performance in photochemical hydrogen generation compared to TiO₂ poly-crystals. These findings open a new horizon of facet junction-engineered nano-catalysts for more robust and efficient energy and environmental applications.

We revealed an interesting facet-dependent electrochemical behavior toward heavy metal ions (HMIs) based on their adsorption behaviors. The (111) facet of Co₃O₄ nanoplates has better electrochemical sensing performance than that of the (001) facet of Co₃O₄ nanocubes. Adsorption measurements and density-functional theory (DFT) calculations reveals that adsorption of HMIs is responsible for the difference of electrochemical properties. Our combined experimental and theoretical studies provide a solid hint to explain the mechanism of electrochemical detection of HMIs using nanoscale metal oxides. Furthermore, this study not only suggests a promising new strategy for designing high performance electrochemical sensing interface through the selective synthesis of nanoscale materials exposed with different well-defined facets, but also provides a deep understanding for a more sensitive and selective electroanalysis at nanomaterials modified electrodes.