Engineering a Ce Promoter into a Three-Dimensional Porous MoC@NC Heterostructure for Hydrogen Evolution Electrocatalysis via Weakening the Mo-H Bond Strength.

The pursuit of highly efficient electrocatalysts for the alkaline hydrogen evolution reaction (HER) is of paramount importance for water splitting. However, it is still a formidable task in MoC-based materials because of the agglomeration and strong Mo-H binding of MoC units. Herein, a novel CeOCl-CeO/MoC heterostructure nesting within a three-dimensional porous nitrogen-doped carbon matrix has been designed and used for catalyzing HER via simultaneous morphology and heterointerface engineering.

Thermal modulation of surface-enhanced Raman scattering and plasmon-induced catalysis in Ag nanoparticle/ZnO microrod composites.

The surface-enhanced Raman scattering (SERS) performance and photocatalytic degradation of dye molecules absorbed on Ag nanoparticle-decorated ZnO microrods are investigated at 20 and 50 °C. The role of temperature in the mechanism is elucidated. This work provides insight into the optimization of temperature-dependent plasmon-induced catalysis using similar materials.

Engineering Interfacial Built-in Electric Field in Polymetallic Phosphide Heterostructures for Superior Supercapacitors and Electrocatalytic Hydrogen Evolution.

Herein, a patterned rod-like CoP@NiCoP core-shell heterostructure is designed to consist of CoP nanowires cross-linked with NiCoP nanosheets in tight strings. The interfacial interaction within the heterojunction between the two components generates a built-in electric field that adjusts the interfacial charge state and create more active sites, accelerating the charge transfer and improving supercapacitor and electrocatalytic performance. The unique core-shell structure suppresses the volume expansion during charging and discharging, achieving excellent stability.

Mechanical properties of hydrogenated ψ-graphene.

Context: Hydrogenation is an effective way to open a band gap of the metallic ψ-graphene, expanding its application in electronics. Evaluating the mechanical properties of hydrogenated ψ-graphene, especially the effect of hydrogen coverage, is also crucial to the application of ψ-graphene. Here, we demonstrate the mechanical properties of ψ-graphene depend closely on the hydrogen coverage and arrangement.

Bending modulus of the rippled graphene: the role of thickness.

Bending modulus is a key parameter to characterize the stiffness of materials. Commonly, it is believed that the bending modulus is closely related to the thickness as described by the thin plate theory. However, the thin plate theory fails in multilayer van der Waals materials like multilayer graphene, suggesting a more complex relationship between the bending modulus and thickness.

Boosting Hydrogen Evolution Electrocatalysis via Regulating the Electronic Structure in a Crystalline-Amorphous CoP/CeO p-n Heterojunction.

The modulation of the electronic structure is the effective access to achieve highly active electrocatalysts for the hydrogen evolution reaction (HER). Transition-metal phosphide-based heterostructures are very promising in enhancing HER performance but the facile fabrication and an in-depth study of the catalytic mechanisms still remain a challenge. In this work, the catalytically inactive n-type CeO is successfully combined with p-type CoP to form the CoP/CeO heterojunction.

Remote Passivation in Two-Dimensional Materials: The Case of the Monolayer-Bilayer Lateral Junction of MoSe.

Two-dimensional (2D) monolayer-bilayer (ML-BL) lateral junctions (LJs) have recently attracted attention due to their straightforward synthesis and resulting clean interface. Such systems consist of an extended ML with a secondary layer present only over half of the system, leading to an interface that is associated with the terminating edge of the secondary half layer. Our first-principles calculations reveal that the edges of the half layer completely lack reconstruction in the presence of unintentional dopants, in this case, Re.

Synergically engineering defect and interlayer in SnS for enhanced room-temperature NO sensing.

Defect and interlayer engineering are considered as two promising strategies to alter the electronic structures of sensing materials for improved gas sensing properties. Herein, ethylene glycol intercalated Al-doped SnS (EG-Al-SnS) featuring Al doping, sulfur (S) vacancies, and an expanded interlayer spacing was prepared and developed as an active NO sensing material. Compared to the pristine SnS with failure in detecting NO at room temperature, the developed EG-Al-SnS exhibited a better conductivity, which was beneficial for realizing the room-temperature NO sensing.

Theoretical study of the influence of doped niobium on the electronic properties of CsPbBr.

In the family of inorganic perovskite solar cells (PSCs), CsPbBr has attracted widespread attention due to its excellent stability under high humidity and high temperature conditions. However, power conversion efficiency (PCE) improvement of CsPbBr-based PSCs is markedly limited by the large optical absorption loss coming from the wide band gap and serious charge recombination at interfaces and/or within the perovskite film. In this work, using density functional theory calculations, we systemically studied the electronic properties of niobium (Nb)-doped CsPbBr with different concentration ratios.

Tunable bending modulus and bending limit of oxidized graphene.

Graphene is highly flexible and widely used in flexible devices. However, is the oxidized graphene more flexible than graphene? This is still under debate between simulations and experiments. By employing density functional theory calculations, we show that the bending modulus of oxidized graphene is quite tunable by changing the type and coverage of the functional groups, as well as the bending direction.

Hole defects and nitrogen doping in graphene: implication for supercapacitor applications.

One great challenge for supercapacitor is to achieve high energy capacity and fast charge/discharge rates simultaneously. Porous graphene with large surface area is a promising candidate for electrode materials of supercapacitor. Using first-principles calculations and non-equilibrium Green's function technique, we have explored the formation energies, mechanical properties, diffusion behaviors and electrical conductance of graphene sheets with various hole defects and/or nitrogen doping.

Electromechanical properties of zigzag-shaped carbon nanotubes.

Atomic structural models of zigzag-shaped carbon nanotubes (Z-CNTs) were constructed by periodically introducing pentagons and heptagons into pristine CNTs. In terms of formation energies, the Z-CNTs present comparable energetic stabilities to those of the pristine CNTs and are more stable than C60 fullerene. The mechanical properties of these Z-CNTs, including the Young's modulus, intrinsic strength and failure behaviour, were systematically investigated by first-principles computations.

Solid-solution semiconductor nanowires in pseudobinary systems.

Pseudobinary solid-solution semiconductor nanowires made of (GaP)(1-x)(ZnS)(x), (ZnS)(1-x)(GaP)(x) and (GaN)(1-x)(ZnO)(x) were synthesized based on an elaborative compositional, structural, and synthetic designs. Using analytical high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS), we confirmed that the structure uniformity and a lattice match between the two constituting binary components play the key roles in the formation of quaternary solid-solution nanostructures. Electrical transport measurements on individual GaP and (GaP)(1-x)(ZnS)(x) nanowires indicated that a slight invasion of ZnS in the GaP host could lead to the abrupt resistance increase, resulting in the semiconductor-to-insulator transition.

Mechanical properties of graphene oxides.

The mechanical properties, including the Young's modulus and intrinsic strength, of graphene oxides are investigated by first-principles computations. Structural models of both ordered and amorphous graphene oxides are considered and compared. For the ordered graphene oxides, the Young's modulus is found to vary from 380 to 470 GPa as the coverage of oxygen groups changes, respectively.