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Transition bimetallic sulfides show significant promise for energy‐related applications because of their plentiful active sites and synergistic redox activity. However, limited pore size and low‐conductivity issues hinder their application. The structure of NiCo–S with rich sulfur vacancies is first predicted by density functional theory (DFT) calculations. Different sulfur vacancy concentrations are modeled by DFT calculations, and the results confirm that sulfur vacancies enhance the conductivity of the electrode material and are more beneficial for the adsorption of OH* species. It is verified by the differential charge density that the electric field formed on the surface of the electrode can lead to strong interfacial interactions by electron aggregation, which promotes electron/ion transfer kinetics. Furthermore, NiCo–S nanosheets are prepared on carbon cloth enriched with different concentrations of sulfur vacancies (denoted as NiCo‐Sv‐x, with x representing the concentration of sulfur vacancies) by sulfide etching NiCo‐MOF and annealing under H2/Ar atmosphere. The NiCo‐Sv‐x electrodes obtained are applied to the cathode of supercapacitors and the anode of the oxygen evolution reaction. Through combining experimental and theoretical analysis, the effect of vacancy defect engineering on the electrochemical performance of the electrode materials is further confirmed. [ABSTRACT FROM AUTHOR]

Two-dimensional flexible materials with both piezoelectric and ferroelectric properties are regarded as the holy grail for realizing ultrathin functional electronic devices, which can be used in electronic flexible skin, high-performance storage, and medical diagnostic devices. However, the piezoelectric coefficients found in current two-dimensional (2D) piezoelectric-ferroelectric materials are comparatively limited in magnitude. Based on first-principles calculations, we demonstrate that 2D ThOTe monolayers exhibit not only remarkable flexibility in their mechanical properties (K/G > 1.75), but also exceptional piezoelectric and ferroelectric characteristics when subjected to strain engineering. Especially, they display an extraordinarily large piezoelectric constant, e11 = 13 181.19 pC m−1, and an impressively high piezoelectric coefficient of d11 = 354.95 pm V−1 at a tensile strain of 14%. Simultaneously, we discovered that the ThOTe monolayer possesses ferroelectric properties with an intrinsic electrode polarization, primarily aligned along the x-axis. The results introduce an innovative approach to explore ferroelectric materials within giant piezoelectric substances and provide valuable insights and references for the development of high-performance giant piezoelectric sensors, electronic devices and memories. [ABSTRACT FROM AUTHOR]

Tin(IV) oxide (Sn3O4) is layered tin and exhibits mixed valence states. It has emerged as a highly promising visible-light pho-tocatalyst, attracting considerable attention. This comprehensive review is aimed at providing a detailed overview of the latest advancements in research, applications, advantages, and challenges associated with Sn3O4 photocatalytic nanomaterials. The fundamental concepts and principles of Sn3O4 are introduced. Sn3O4 possesses a unique crystal structure and optoelectronic properties that allow it to absorb visible light efficiently and generate photoexcited charge carriers that drive photocatalytic reactions. Subsequently, strategies for the control and improved performance of Sn3O4 photocatalytic nanomaterials are discussed. Morphology control, ion doping, and hetero-structure construction are widely employed in the optimization of the photocatalytic performance of Sn3O4 materials. The effective implementation of these strategies improves the photocatalytic activity and stability of Sn3O4 nanomaterials. Furthermore, the review explores the diverse applications of Sn3O4 photocatalytic nanomaterials in various fields, such as photocatalytic degradation, photocatalytic hydrogen production, photocatalytic reduction of carbon dioxide, solar cells, photocatalytic sterilization, and optoelectronic sensors. The discussion focuses on the potential of Sn3O4-based nanomaterials in these applications, highlighting their unique attributes and functionalities. Finally, the review provides an outlook on the future development directions in the field and offers guidance for the exploration and development of novel and efficient Sn3O4-based nanomaterials. Through the identification of emerging research areas and potential avenues for improvement, this review aims to stimulate further advancements in Sn3O4-based photocatalysis and facilitate the translation of this promising technology into practical applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials with simultaneous magnetic semiconducting properties and a negative Poisson's ratio are crucial for fabricating multifunctional electronic devices. However, progress in this area has been generally constrained. Based on first-principles calculations, we engineered a 2D Ni-based oxyhalide with a honeycomb lattice structure. It was observed that the NiCl2O8 monolayer exhibits both high- and low-buckling states in its geometry, along with intrinsic magnetic semiconductor properties in its electronic structure. Importantly, we demonstrated that the magnetic ordering of the NiCl2O8 lattice is susceptible to applied strain, which resulted in a phase transition from paramagnetic to ferromagnetic under biaxial strain. The Curie temperature was also evaluated using Monte Carlo simulations within the Ising model. Additionally, our research uncovered that the 2D NiCl2O8 lattice chain displays a negative Poisson's ratio (NPR) along the z-direction. The triangular hinge structure in its centrosymmetric configuration was identified as the origin of this unique phenomenon. The coexistence of NPR and magnetic phase transition properties in the NiCl2O8 lattice makes it quite promising for applications in nanoelectronic and spintronic devices. [ABSTRACT FROM AUTHOR]

The preparation of various nanomaterials with hierarchical structure from metal–organic frameworks (MOFs) has attracted a lot of attention due to their abundant diversity in composition and structure. In this work, we developed a method to synthesize a three-dimensional (3D) Cu/CuxO/NC (nitrogen carbon) composite by pyrolysis of Cu-MOF. The obtained Cu/CuxO/NC composite has a flower-like structure assembled with nanosheets. It displays both excellent electrochemical catalytic and mimic enzyme activities. It was successfully applied to fabricate an electrochemical glucose sensor which has a linear response in the range of 0–2.0 mM and 2.0–5.0 mM with a detection limit of 3.5 μM, and electrochemical measurements indicate that the Cu/CuxO/NC-modified electrode possesses high selectivity toward glucose. Moreover, Cu/CuxO/NC also acted as a horseradish peroxidase (HRP) mimic enzyme and displayed obvious enzymatic catalytic activities for tetramethylbenzidine (TMB) and dopamine (DA) in the presence of H2O2. To demonstrate the proof-of-concept, it was used to construct an enzymatic sensor for glucose. The obtained 3D Cu/CuxO/NC nanostructures present good prospects in sensor platform construction for other biomolecules. [ABSTRACT FROM AUTHOR]