Facet junction engineering for enhanced SERS activity of Ag/CuO composite substrates.

Featuring ultra-high sensitivity and molecule-specific detection ability, surface-enhanced Raman scattering (SERS) is suitable for the rapid sensing of trace-level chemicals in biological, environmental, and agricultural samples. Although crystal facet junction engineering is a powerful tool to manipulate the optoelectronic properties of semiconducting materials, its correlation with the SERS sensing activity of noble metal/semiconductor composites has still not been clarified. In this work, Ag was deposited on CuO nanocrystals enclosed by different facets, including {100} (cube), {111} (octahedron), and {100}/{111} (truncated octahedron), and a detailed study of their SERS performance was carried out.

CdS-based Schottky junctions for efficient visible light photocatalytic hydrogen evolution.

Heterojunctions photocatalysts play a crucial role in achieving high solar-hydrogen conversion efficiency. In this work, we mainly focus on the charge transfer dynamics and pathways for sulfides-based Schottky junctions in the photocatalytic water splitting process to clarify the mechanism of heterostructures photocatalysis. Sulfides-based Schottky junctions (CdS/CoP and CdS/1T-MoS) were successfully constructed for photocatalytic water splitting.

Designing highly efficient oxygen evolution reaction electrocatalyst of high-entropy oxides FeCoNiZrO: Theory and experiment.

The correlations between the experimental methods and catalytic activities are urgent to be defined for the design of highly efficient catalysts. In this work, a new oxygen evolution reaction electrocatalyst of high-entropy oxide (HEO) FeCoNiZrO was designed and analyzed by experimental and theoretical methods. On account of the shortened coordinate bond along with the increased annealing temperature, the atomic/electronic structures of active site were adjusted quantitatively with the aid of the pre-designed correlator of electron density, which contributed to adjust the catalytic activity of HEO specimens.

Engineering the crystal facets of α-MnO nanorods for electrochemical energy storage: experiments and theory.

Crystal facet engineering is an effective strategy for precisely regulating the orientations and electrochemical properties of metal oxides. However, the contribution of each crystal facet to pseudocapacitance is still puzzling, which is a bottleneck that restricts the specific capacitance of metal oxides. Herein, α-MnO nanorods with different exposed facets were synthesized through a hydrothermal route and applied to pseudocapacitors.

VASERP: An Adaptive, Lightweight, Secure, and Efficient RFID-Based Authentication Scheme for IoV.

With the rapid growth in wireless communication and IoT technologies, Radio Frequency Identification (RFID) is applied to the Internet of Vehicles (IoV) to ensure the security of private data and the accuracy of identification and tracking. However, in traffic congestion scenarios, frequent mutual authentication increases the overall computing and communication overhead of the network. For this reason, in this work, we propose a lightweight RFID security fast authentication protocol for traffic congestion scenarios, designing an ownership transfer protocol to transfer access rights to vehicle tags in non-congestion scenarios.

Sulfur Vacancy-Rich CuS for Improved Surface-Enhanced Raman Spectroscopy and Full-Spectrum Photocatalysis.

There are growing interests in the development of bifunctional semiconducting nanostructures for photocatalysis and real-time monitoring of degradation process on catalysts. Defect engineering is a low-cost approach to manipulating the properties of semiconductors. Herein, we prepared CuS nanoplates by a hydrothermal method at increasing amounts of thioacetamide (CS-1, CS-2, and CS-3) and investigated the influence of sulfur vacancy (V) on surface-enhanced Raman spectroscopy (SERS) and photocatalysis performance.

Experimental and theoretical evaluation of crystal facet exposure on the charge transfer and SERS activity of ZnO films.

Semiconductors exhibit great potential as a surface enhanced Raman scattering (SERS) substrate due to their low cost, good stability and biocompatibility. However, the extensive application of semiconductors has been restricted by their intrinsically low SERS sensitivity. It is urgently required to design uniform metal oxide substrates with enhanced charge transfer and SERS activity.

CdInS/In(OH)/NiCr-LDH Multi-Interface Heterostructure Photocatalyst for Enhanced Photocatalytic H Evolution and Cr(VI) Reduction.

The development of highly active and stable photocatalysts, an effective way to remediate environment pollution and alleviate energy shortages, remains a challenging issue. In this work, a CdInS/In(OH) nanocomposite was deposited in-situ on NiCr-LDH nanosheets by a simple hydrothermal method, and the obtained CdInS/In(OH)/NiCr-LDH heterostructure photocatalysts with multiple intimate-contact interfaces exhibited better photocatalytic activity. The photocatalytic H evolution rate of CdInS/In(OH)/NiCr-LDH increased to 10.

Designing of Highly Efficient Oxygen Evolution Reaction Electrocatalysts Utilizing A Correlation Factor: Theory and Experiment.

The theoretical prediction of the catalytic activity is very beneficial for the design of highly efficient catalysts. At present, most theoretical descriptors focus on estimating the catalytic activity and understanding the enhancement mechanism of catalysts, while it is also quite important to find a factor to correlate the descriptors with preparation methods. In this work, a correlation factor, the d electron density of transition metal ions, was developed to correlate the d band center values of transition metal ions with the preparation methods of amorphization and Al introduction.

Experimental and Theoretical Investigation of the Effect of Oxygen Vacancies on the Electronic Structure and Pseudocapacitance of MnO.

Defect engineering is an effective way to modulate the intrinsic physicochemical properties of materials. In this work, δ-MnO with oxygen vacancies is fabricated by a simple oxidation or reduction process, and the relationship between the electronic structure and pseudocapacitance is systematically studied through experimental analysis and theoretical calculations. The peaks in the Raman spectra of the as-prepared samples are shifted compared with those of pure MnO and the Mn /Mn ratio and O species content also change after the introduction of oxygen vacancies.

Waste bones derived nitrogen-doped carbon with high micropore ratio towards supercapacitor applications.

Fabrication of high-performance electrodes from waste biomass has attracted increasing attention among the energy storage and conversion field. In this work, we have synthesized nitrogen-doped activated carbon by a simultaneous pyrolysis/activation method from waste bones. It is found that the specific surface area and pore structure of as-synthesized carbon depends on the carbonization temperature (500-800 °C), and the highest specific surface area is 1522 m g.

Unexpected monoatomic catalytic-host synergetic OER/ORR by graphitic carbon nitride: density functional theory.

Although single metal atoms (SMAs) have been extensively investigated as unique active sites in single-atom catalysts, the possible active sites of the host catalysts have been unfortunately neglected in previous studies. In single-atom catalysts, the SMAs can promote the chemical and catalytic activities of host atoms, which may act as secondary active sites, resulting in a significant synergistic effect on the catalytic performance. Using density functional theory calculations, we studied the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) on two different types of active sites: single metal (M1) atoms and the neighboring host atoms of several M1/g-C3N4 samples.

CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions.

(H, Li)Br and LiOH Solvation Bonding Dynamics: Molecular Nonbond Interactions and Solute Extraordinary Capabilities.

We resolved the O:H-O bond transition from the mode of ordinary water to its hydration in terms of its phonon stiffness (vibration frequency shift Δω), order of fluctuation (line width), and number fraction (phonon abundance), f(C) = N/N. The f(C) follows f(C) = 0, f(C) ∝ f(C) ∝ C, and f(C) ∝ 1 - exp(-C/C) toward saturation with C being the solute concentration. The invariant df(C)/dC suggests that the solute forms a constantly sized hydration droplet without responding to interference of other ions because its hydrating HO dipoles fully screen its electric field.

Compression icing of room-temperature NaX solutions (X = F, Cl, Br, I).

In situ Raman spectroscopy revealed that transiting H2O/NaX (∼64) solutions into an ice VI phase and then into an ice VII phase at a temperature of 298 K requires excessive pressures with respect to pure water. The increase of the critical pressures varies with the solute type in the Hofmeister series order: X = I > Br > Cl > F ∼ 0. The results suggest that the solute hydration creates electric fields that lengthen and soften the O:H nonbond and meanwhile shorten and stiffen the H-O bond through O-O Coulomb repulsion.

Atomic under-coordination fascinated catalytic and magnetic behavior of Pt and Rh nanoclusters.

Density functional theory (DFT) calculations with local spin density discrimination have been performed to examine the effect of atomic under-coordination on the catalytic and magnetic properties of cuboctahedral (CO) and marks decahedral (MD) structured Pt and Rh nanoclusters. Consistency between theoretical calculations and experimental observations confirmed the predictions based on the framework of bond-order-length-strength (BOLS) correlation and nonbonding electron polarization (NEP) notations. The BOLS-NEP notation suggests that the shorter-and-stronger bonds between under-coordinated atoms induce local densification and quantum entrapment of core electrons, which then polarize the otherwise conducting electrons and result in shifts of the binding energy.

Skin-resolved local bond contraction, core electron entrapment, and valence charge polarization of Ag and Cu nanoclusters.

Consistency between density functional theory (DFT) calculations and experimental observations confirmed our predictions on the behaviour of local bonds, and the electron binding energy of cuboctahedral and Marks decahedral structures of Ag and Cu nanoclusters. The shorter and stronger bonds between under-coordinated atoms cause local densification and quantum entrapment of the core electrons, which polarize the otherwise conducting electrons (valence electrons). Such strong localization may result in extraordinary catalytic and plasmonic properties in Ag and Cu nanoclusters.

Morphological control and photoluminescence of zinc oxide nanocrystals.

Nanocrystals of the wide band gap semiconductor zinc oxide of controllable morphologies were synthesized by a simple thermal decomposition method. The predominating factor in determining the morphology (spheres, triangular prisms, and rods) was the solvent, selected on the basis of coordinating power. The nanoparticles were structurally analyzed, and the photoluminescence of each shape was compared.