Oxide Research Articles

Insights into Selective Sensitivity of In2O3-CuO Heterojunction Nanocrystals to CH4 over CO and H2: Experiments and First-Principles Calculations.

Metal oxide semiconductor gas sensors have demonstrated exceptional potential in gas detection due to their high sensitivity, rapid response time, and impressive selectivity for identifying various sorts of gases. However, selectively distinguishing CH4 from those of CO and H2 remains a significant challenge. This difficulty primarily stems from the weakly reducing nature of CH4, which results in a low adsorption response and makes it prone to interference from stronger reducing gases in the surroundings. Herein, we synthesized In2O3-xCuO nanocomposites using a hydrothermal method to explore their gas sensing properties toward CH4, CO, and H2. Characterization tests confirmed the successful preparation of In2O3-xCuO nanocomposites with different In:Cu molar ratios and the formation of a p-n heterojunction. The gas sensing test results indicated that the In2O3-2.1CuO nanocomposites calcined at 500 °C and measured at 350 °C displayed a p-type response for CH4 and an n-type response for CO and H2, allowing for accurate differentiation of CH4 from CO and H2. Moreover, the In2O3-2.1CuO sensor also showed excellent stability and reproducibility across all three gases. First-principles calculations revealed distinct changes in the electronic structure of the In2O3-CuO heterojunction upon adsorption of CH4, CO, and H2, a finding that aligns with empirical evidence. The gas selectivity mechanism was effectively explained by variations in the energy band gap, driven by electrical behavior during the adsorption process. This work suggests a promising approach for developing selective gas sensors capable of detecting weakly reducing gases.

Green synthesis of metal oxide nanoparticles using plant extract, its structural and optical properties and application

The nanoparticles being the most utilized invention of nanoscience and technology, which is used in many aspects of science and medicine. These remarkable utilization of particles is due to their diverse properties at nano level. The chemical and physical approach to formation of nanoparticles are toxic to surroundings also leading to less efficient usage of them in medical perspective. In this article green synthesis of cobalt ferrite nanoparticles is done by sol-gel auto combustion using Caralluma Tuberculata extract as reducing agent, iron nitrate and cobalt nitrate as precursor salts. Cobalt ferrite nanoparticles are used in many aspects for certain properties such as antimicrobial activities the synthesized particles were characterized using different techniques such as UV Spectroscopy, SEM, FTIR, XRD,EDX. The antibacterial activity of cobalt ferrite nanoparticles is performed which shows remarkable results by increasing the inhibition zone for both E coli and Staphylococcus bacteria

Influence of gaseous dielectrics on the wettability of Al-6061 alloy using dry μ-electrical discharge milling

Superhydrophobic surfaces are essential for applications such as self-cleaning and corrosion resistance. This study explores the fabrication of superhydrophobic surfaces on Al-6061 alloy using dry micro electrical discharge milling (μEDM milling) and investigates the effects of gaseous dielectrics on wettability under atmospheric conditions. Surfaces machined in an oxygen environment showed a surface area roughness (Sa) of 4.68 μm, 73.3 % higher than those machined in argon, attributed to enhanced metal oxide formation. Energy Dispersive X-ray Analysis (EDAX) indicated a significantly elevated O/Al atomic ratio of 0.80 for oxygen-machined samples, which was 73.9 % greater than argon-machined samples, suggesting the presence of hydrophilic compounds such as AlO(OH) and Al2O3. Additionally, X-ray Photoelectron Spectroscopy (XPS) revealed that Al2O3 peaks on oxygen-machined surfaces were broadened and shifted to higher binding energies, correlating with decreased contact angles and increased surface hydrophilicity. These results suggest that using oxygen as a dielectric in theelectrical discharge machining (EDM) process promotes oxide layer formation, resulting in hydrophilic characteristics, while machining in argon encourages organic adsorption and greater hydrophobicity. The findings of this research provide insights that can inform future efforts to tailor surface properties for advancements in aerospace, automotive, and biomedical engineering applications.

Design of alkali metal oxide adsorbent for direct air capture: Identification of physicochemical adsorption and analysis of regeneration mechanism

Direct air capture (DAC) represents an advanced negative carbon emission technology, with the key being high-performance CO2 adsorbents. First, this work carefully identifies CO2 physisorption and chemisorption by CaO/HcATP (CaO loaded on acid-modified attapulgite) as DAC adsorbent. The chemisorption of amorphous "CaO" plays a crucial role in both the adsorption capacity and rate, with contributions of 66.8 % and 50.85 %, respectively. The adsorption capacity of CaO/HcATP is only 212.4 ± 25.7 µmol/g via the simple CO2 physisorption and improved by 426.7 µmol/g owning to the chemisorption of amorphous CaO. Second, the concentration of silanol groups on CaO/HcATP plays a pivotal role in the adsorption process. The concentration of silanol groups decreases to 3.85 OH/nm2 after undergoing 30 cycles of adsorption-desorption. Then it increases to 9.54 OH/nm2 by adsorbing the moisture in the air, resulting in a recovered adsorption capacity of 90.7 %. Furthermore, the pseudo-first-order adsorption kinetics model effectively predicted the experimental results. Finally, the dual loop of CO2 capture and regeneration is summarized using the CaO/HcATP as DAC adsorbent. The amorphous "CaO" interacts with the surface silanol of HcATP, synergistically capturing CO2 in the form of "CaO···CO2", which reduces desorption energy consumption. The wetting property of HcATP contributes to the regeneration of CaO/HcATP. This work contributes to establishing fundamental principles for designing cost-effective DAC adsorbents.

Ternary metal oxide carbon composite as high-performance electrode material for supercapacitor applications

Recently, ternary metal oxides carbon composites recognized as metal organic frameworks (MOFs) have gained striking attention for supercapacitor electrode material due to high surface area, porosity, chemical stability, tunable properties, redox activity, and eco-friendly material. ZIF-67 is a novel MOF possessing these characteristics. Therefore, the present work reports the development of ternary iron-nickel–cobalt ZIF-67 composites (FeNiCo ZIF-67) using co-precipitation method with the variation in molar concentration of iron oxide, nickel oxide, and cobalt oxide. Physico-chemical characterizations of developed materials were investigated through X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray (EDX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) to confirm the successful formation of composites and structure, morphology. Then, the electrodes were fabricated for all three synthesized composites and electrochemical analyses such as cyclic voltammetry (CV), galvanic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) were performed. The results revealed the porous polyhedral structure of FeNiCo ZIF-67 with different compositions consisting of interconnected nanoparticles played an important role in increasing the charge storage capacity of the material. Among the composites, FeNiCo ZIF-67 (1:2:1) electrode material achieved the highest specific capacitance of 532.7 F/g at a current density of 1 A/g. FeNiCo ZIF-67 (1:2:1) exhibited maximum electrochemical active surface area 89.12. Electrochemical impedance spectroscopy (EIS) demonstrated the minimal resistance of 7.8 Ω by FeNiCo ZIF-67 (1:2:1) composite electrode compared to the other two electrode materials. Cyclic stability study revealed the capacitance retention of 91 % after 10,000 continuous charge discharge cycles at a current density of 10 A/g. Electrode material demonstrated an outstanding electrochemical performance, and this work could provide a simple strategy to fabricate FeNiCo ZIF-67 nanostructured electrode materials for supercapacitors.

Low dark current and low voltage germanium avalanche photodetector for a silicon photonic link

Germanium (Ge)-silicon (Si)-based avalanche photodetectors (APDs) featured by a high absorption coefficient in the near-infrared band have gained wide applications in laser ranging, free space communication, quantum communication, and so on. However, the Ge APDs fabricated by the complementary metal oxide semiconductor (CMOS) process suffer from a large dark current and limited responsivity, imposing a critical challenge on integrated silicon photonic links. In this work, we propose a p-i-n-i-n type Ge APD consisting of an intrinsic germanium layer functioning as both avalanche and absorption regions and an intrinsic silicon layer for dark current reduction. Consequently, a Ge APD with a low dark current, low bias voltage, and high responsivity can be obtained via a standard silicon photonics platform. In the experimental measurement, the Ge APD is characterized by a high primary responsivity of 1.1 A/W with a low dark current as low as 7.42 nA and a dark current density of 6.1×10−11 A/μm2 at a bias voltage of −2 V. In addition, the avalanche voltage of the Ge APD is −8.4 V and the measured 3 dB bandwidth of the Ge APD can reach 25 GHz. We have also demonstrated the capability of data reception on 32 Gbps non-return-to-zero (NRZ) optical signal, which has potential application for silicon photonic data links.

Amorphous metal-organic frameworks-derived In2O3 microstructures with abundant oxygen vacancies for superior chlorine gas sensing performance

Metal-organic frameworks (MOFs) are characterized by their porous structures, which provide an exceptionally large specific surface area and a precisely controlled composition. Amorphous MOFs (aMOFs) integrate the diverse properties of MOFs with those of amorphous materials, such as hierarchical morphology and abundant deficiencies. Therefore, aMOFs serve as promising precursors for metal oxides with porous structures and rich vacancies. NH2-MIL-68 (In) is a novel indium-MOF material with promising features. In this research, the amorphous NH2-MIL-68 (In) (aNH2-MIL-68 (In)) was chosen as the template. Indium oxide rough straight rods (a-In2O3 RSRs) with extensive oxygen vacancies were prepared, where a- indicates that the precursor is amorphous. As a result, the a-In2O3 RSRs sensor demonstrated an outstanding gas sensing response towards 2 ppm chlorine (Cl2) at a low temperature of 160℃. This study is the first to report that the aMOFs can be employed as gas sensing materials with superior Cl2 detection capabilities, offering a promising method for real-time gas monitoring.

How to describe the time-dependent dissolution of engineered nanomaterials?

Numerous processes such as solubility, agglomeration/aggregation, or protein corona formation may change over time and significantly affect engineered nanomaterial (ENM) structure, property, and availability, resulting in their reduced or increased toxicological activity. Therefore, understanding the dynamics of these processes is essential for assessing and managing the risks of ENMs during their lifecycle, ensuring safety by design. Of these processes, the importance of solubility (i.e., the ability to release ions from the surface) is undeniable. Thus, we propose a practical approach, the Kalapus equation (KEq), to determine ENMs' dissolution over time. As a proof-of-concept, the KEq was applied to determine the solubility of six commercially used metal and metal oxide nanoparticles over time. The KEq exhibited a higher coefficient of determination (R2=0.995-0.999) than the logarithmic equation (R2=0.835-0.986), and the pseudo-first-order equation (R2=0.915-0.994) over a range of experimental data. The newly introduced Kalapus equation outperformed the logarithmic and pseudo-first-order equations when extrapolating beyond the time range in which solubility was experimentally determined. The mean absolute error in solubility prediction for the KEq was 3.29% and 4.28% for the first and second data points, respectively, significantly lower than the 13.46% and 18.05% observed for the pseudo-first-order/first-order equation. The proposed equation can be used as a part of New Generation Risk Assessment (NGRA) methodology, especially new Integrated Approaches to Testing and Assessments (IATAs).

Mo–V–Al–K–O catalyst for low-temperature oxidative dehydrogenation of propane

Compared with propane dehydrogenation (PDH) technology, oxidative dehydrogenation (ODH) of propane is an effective way to break through the thermodynamic constraints, which has changed the endothermic reaction into exothermic. Meanwhile, coking in PDH was significantly reduced by the presence of an oxidant in ODH of propane. Therefore, ODH of propane has attracted wide interest and has been studied in recent years. However, the contradiction between the conversion of propane and the selectivity of propene was the intrinsic problem of ODH of propane that required further study. In this work, a novel aluminum/potassium-doped mixed metal oxide catalyst Mo1V0.5Al0.02K0.03Ox was synthesized using a simple co-impregnation method, whose selectivity for propene (83.2 %) and conversion of propane (12.7 %) at 300 °C were the best among all other alkali metal/alkaline-earth metal-doped catalysts. The further discussion illustrated that doping potassium and alumina could synergistically adjust the density of acid sites on the catalyst, establishing an equilibrium between high propane conversion and the ideal propene selectivity. After modification, the density of Brønsted acid decreased, leading to an enhancement in the selectivity of propene. Simultaneously, the addition of steam in the feed gas promotes propene to oxygenates and improves the conversion of propane under the condition of constant contact time.

Biosynthesis, characterization of Ag2O nanoparticles for enhancement of antioxidant and photo degradation activities

Silver oxide (Ag2O) nanoparticles were synthesized via Biosynthesis methods using Croton macrotachyus leaf extract silver sulphate (Ag2SO4) was used as precursors and the extract was used in the reactions as reducing, stabilizing and capping agents which is a very easy and inexpensive synthesis method. Metal oxide nanoparticles characterized using UV–visible, TGA, Fourier transform infrared(FTIR),powder X-ray diffraction(XRD), X-ray photoelectron(XPS), and Scanning Electron Microscopy(SEM) with Energy Dispersive X-Ray(EDX) and Transmission Electron Microscopy(TEM), High Resolution Transmission Electron Microscope(HRTEM), and Selected Area Electron (SAED) which is used for determination of crystalline size, morphology,particle size and oxidation state with composition of elements in the sample. Metal oxide nanoparticles have a significant photo catalytic performance under visible light source confirmed that study supported Ag2O spherical structure, which exhibits enhanced photo catalytic activity and anti-oxidant activities as well as the size of the Ag2O nanoparticles was between 16 nm and 21 nm from the XRD(Scherrer equation),SEM & TEM) imaje software and Photo catalytic activity of Ag2O NPs were assessed against methylene blue (MB) dye degradation under natural sunlight illumination for 60 min. This sustainably photo degraded in direct solar irradiance with remarkable degradation percentage which is greater than 96.35 % and Scavenging activities Ag2O nanoparticles enhanced DDPH scavenging activities was 88 %

Data-Science-Informed Operation, Maintenance Practices Reduce Emissions

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper URTeC 3866061, “Reducing Methane Emissions: Implementing Data-Science-Informed Operation and Maintenance Work Practices Using Continuous Monitoring Technology,” by Kathleen Jenkins, Carol A. Brereton, and Alex MacGregor, Qube Technologies, et al. The paper has not been peer reviewed. _ Diverse methods are used by oil and gas operators for methane leak detection and repair (LDAR). Deploying continuous monitoring (CM) point-sensor technologies to an oil and gas facility allows operators to implement novel operation and maintenance work practices to respond efficiently to methane emissions. The authors examine how data-science-driven work practices can result in substantial reduction in methane emissions compared with other LDAR methods. CM Technology CM point sensors track changes in parts per million of methane in the air. When several fixed sensors are deployed at a site, a large area can be surveilled. Using proprietary algorithms based on a plume-dispersion model, the volume and site rate of the methane emission are calculated. The probable location of the emission is estimated and, together with the volume, is shown on a Web-based dashboard that displays the changes in site rate through time. Alerts generated by the CM system allow the operator to respond to leaks more quickly than when waiting for data from an intermittent inspection to provide emission data. CM was deployed by a Permian Basin operator with a desire to operate cleanly, with transparency. The devices were installed with the operator beginning in March 2022 and continue to be active at the time of writing. Alerts generated by the system are delivered to operations personnel, including control-room operators, and investigated by field operators. When the source is identified, repairs are scheduled or completed on the spot and recorded for review. The operator has expanded the deployments throughout the field and uses the data to identify and repair leaks. Theory and Methods The CM devices were deployed around the fence line at several production facilities in the Permian Basin. The optimal number and placement of sensors was determined by analyzing publicly available wind data and sources of emissions at the facility. The CM devices have an inlet port that allows the ambient air to enter the device and flow across a metal oxide sensor. Metal oxide sensors measure the change in conductivity as the air flows across them as a result of the methane adhering to the metal. The change in conductivity, directly correlated with the parts per million of methane in the air, is recorded. Also measured are temperature and wind data, read by temperature sensors and anemometers on each device. This data is sent through a mobile telecommunications network to cloud-based servers that apply an emission-estimation model based on a plume dispersion and a localization algorithm to the data. Cloud services facilitate the transfer of information from devices to Web-based software. Each methane sensor is calibrated in the laboratory before installation by exposing it to known levels of methane. In this process, the temperature and humidity are systematically varied while the methane concentrations are changed and the reported conductivity is recorded. The resulting coefficients of conductivity are stored with the serial number of the device and sent to the device through the mobile network when it is deployed in the field.

Arc characteristic in aluminum alloy double-wire variable polarity double base pulsed gas metal arc welding

The aluminum (Al) alloy double-wire pulsed gas metal arc welding (GMAW) has severe double arc interference issues. To reduce double arc interference, the advantages of double-wire pulsed GMAW and variable-polarity (VP) welding are combined to form Al alloy double-wire VP double base pulsed GMAW. The profile and behavioral characteristics of double arcs are analyzed using high-speed images to assess their physical properties. The arc load characteristics are explored through U-I curves, and the polarity switching process is analyzed from the perspective of double arc coupling. The experimental results showed that arcs with identical polarity are attracted to each other, while arcs with the opposite polarity repel each other. The coupling areas of two arcs with different polarities are therefore different; the electrode positive (EP) arc has a broader profile, while the electrode negative (EN) arc has an elongated profile. The stability of the leading arc is also affected by the polarity switching of the trailing arc. During the EN phase, the trailing arc can climb up to 2–3 times the wire diameter along the wire to search for metal oxide. The EN arc is more stable than the EP arc, and the EN peak arc has a load impedance that is 0.4–0.6 times lower than that of the EP peak arc. The polarity switching from EP to EN is easier due to the larger arc coupling area while switching from EN to EP is more difficult because of the thin arc coupling area. Regardless of polarity, the arc coupling area can provide charged particles for the arc to a certain extent and reduce the probability of arc extinguishing due to polarity switching.

Recent Progress in Direct X-Ray Detectors Based on Metal Oxide Wide Bandgap Semiconductors: A Review

Recent Progress in Direct X-Ray Detectors Based on Metal Oxide Wide Bandgap Semiconductors: A Review

Application of Solution-Processed High-Entropy Metal Oxide Dielectric Layers with High Dielectric Constant and Wide Bandgap in Thin-Film Transistors

High-k metal oxides are gradually replacing the traditional SiO2 dielectric layer in the new generation of electronic devices. In this paper, we report the production of five-element high entropy metal oxides (HEMOs) dielectric films by solution method and analyzed the role of each metal oxide in the system by characterizing the film properties. On this basis, we found optimal combination of (AlGaTiYZr)Ox with the best dielectric properties, exhibiting a low leakage current of 1.2 × 10−8 A/cm2 @1 MV/cm and a high dielectric constant, while the film’s visible transmittance is more than 90%. Based on the results of factor analysis, we increased the dielectric constant up to 52.74 by increasing the proportion of TiO2 in the HEMOs and maintained a large optical bandgap (>5 eV). We prepared thin film transistors (TFTs) based on an (AlGaTiYZr)Ox dielectric layer and an InGaZnOx (IGZO) active layer, and the devices exhibit a mobility of 18.2 cm2/Vs, a threshold voltage (Vth) of −0.203 V, and an subthreshold swing (SS) of 0.288 V/dec, along with a minimal hysteresis, which suggests a good prospect of applying HEMOs to TFTs. It can be seen that the HEMOs dielectric films prepared based on the solution method can combine the advantages of various high-k dielectrics to obtain better film properties. Moreover, HEMOs dielectric films have the advantages of simple processing, low-temperature preparation, and low cost, which are expected to be widely used as dielectric layers in new flexible, transparent, and high-performance electronic devices in the future.

Oral Toxicity of Magnesium Oxide Nanoparticles, MgO NPs on Liver in Male Rats

Nanotechnology is an emerging technology that has led to the nanomedicine development, which involves nanoparticles that exist in the natural world. Nanoparticle is an ultrafine unit with dimensions measured in nanometers. They are created as a result of human activities, and have recently been used in various biomedical applications, consumer products, and commercially, etc. Magnesium oxide nanoparticles (MgO NPs), among the known metal oxides, have attracted a vast scientific interest. Therefore, human health can be at risk of continuous exposure. However, the toxic effects of MgO NPs should be assessed with their increased applications. The present study aimed to investigate the physiological and histological, alterations induced by the MgO nanoparticles in hepatocytes of male rats through oral route with (250, and 1000) mg/kg for (14, 28, and 56) days. Fifty-four male mature rats, (2.5 - 3 months old) were divided randomly into nine groups of six rats each, gavaged with MgO NPs (which were purchased from US Research Nanomaterials, Inc). The results obtained revealed highly significant increase (p<0.01) in aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and total bilirubin. The histopathological examinations showed sinusoidal dilatation, atrophy of hepatocytes, depletion of glycoprotein, focal area of necrosis, inflammatory cells infiltration and apoptosis. MgO NPs demonstrated potential harm to liver tissue, and human health.

Catalytic depolymerization of poly(ethylene terephthalate) plastic into value-added monomers using metal-modified mesoporous silica

The glycolysis of poly(ethylene terephthalate) (PET), a polymer extensively used in food packaging, into bis(2-hydroxyethyl) terephthalate (BHET) monomers was investigated using mesoporous silica supported by metal oxide as catalysts. Among these, a catalyst composed of ZnO supported on KIT-6 (5%ZnO/KIT-6) showed an effective performance in PET glycolysis, achieving a BHET yield of 92.1% with complete conversion of PET. Additionally, the catalyst demonstrated exceptional reusability and high efficiency in handling post-consumer PET plastics, with BHET yields reaching up to 89%. Characterization studies revealed that the highly dispersed ZnO nanoparticles trapped in KIT-6 channels formed strong interactions with surface Si-OH groups, leading to an enhanced acid strength and an increased number of acid sites, which significantly improved PET depolymerization. This study presents an innovative solution for the recycling of PET plastic, contributing to industrial development and reducing the impact of plastic waste.

Unraveling the Effect of Electric Discharge Machining Current on the Fabrication of 3D Mo‐Doped VO0.2 Integrated Microsupercapacitors

Vanadium oxides are widely used for microsupercapacitors (MSCs) due to their multiple‐valence and high theoretical capacitance. A conceptually new approach of electric discharge machining (EDM) with computer‐aided control is developed to one‐step fabricate Mo‐doped VO0.2‐based electrodes and devices with designable geometry. The results demonstrate that the Mo@VO0.2 integrated interdigital MSCs (IIMSCs) with the narrowest electrode distance of 300 μm show the best capacitive performance, which is furtherly manifested by the electric field simulation. Moreover, this work concentrates on expounding the relationships between the EDM machining current, surface morphology of Mo@VO0.2, and the capacitive behavior of Mo@VO0.2 IIMSCs. Compared to the machining current of 2 and 3 A, the machining current of 1 A facilitates synthesizing smaller Mo@VO0.2 particles with more porosity and higher surface area and thus achieving a larger capacitance value for Mo@VO0.2 IIMSCs device, which is achieving 32 mF cm−2 at 1 mV s−1, working well up to an ultrahigh scan rate of 30 V s−1, and obtaining a good cyclic stability of 88.61% after 5000 cycles. Moreover, this innovative EDM approach opens a new avenue for one‐step synthesis of various ceramic metal oxides for various microdevices such as microbatteries and microsensors.

Designing ZrO2-blended nanocomposite MIM capacitors for future OFET applications and their characterizations

Organic field-effect transistors (OFETs) have been exploited as sensors for a variety of applications due to their excellent advantages over diodes and other electronic devices. Capacitors are one of the key components of the OFET designs that consist of a dielectric layer sandwiched between two parallel metal plates. The dielectric layer should be thin and/or have a high k constant value to achieve a high capacitance value (Ci, areal capacitance), so more charge carriers can be accumulated at the interface between the dielectric and the organic semiconductor, for OFETs to operate under low voltage (< 3 V). In this study, high-k nanocomposites (NCs) of ZrO2 metal oxide ceramic nanoparticles (NPs) in varying concentrations blended in two different polymer matrixes, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and cyanoethyl cellulose (CEC) have been utilised as the dielectric layer in metal-insulator-metal (MIM) capacitors. The physical and electrical properties of fabricated MIM capacitors were evaluated. The measured areal capacitance, Ci, values demonstrated a gradual rise with increasing ZrO2 metal oxide content in both polymer matrixes. ZrO2-PVDF-HFP-based capacitors exhibited a two-fold increase in Ci, 91.86 ± 6.1 nF/cm2 (a 140 % increase) for 10 wt % NP content. Similarly, areal capacitance values of 76 ± 3.03 nF/cm2 (a 45 % rise) was measured on MIMs using CZ10 dielectric layer. High average dielectric constant (k) values of 28.61 and 35.68 for CZ5 and PZ5, respectively) were obtained. As expected, leakage current density increased for higher NP % in polymer matrixes. Nevertheless, all MIMs yielded average leakage current density < 1.75 × 10−6 (A/cm2) at 2 V. Therefore, the reported nanocomposites are suitable dielectric layers for OFETs and as platforms for gas, chemical and photoactivated sensing devices.

Drastically Promoting Rate Capability via Dual-Cations Intercalation of V2O5 Enabling Rapid Zinc-Ion Storage.

Layered vanadium pentoxide (V2O5) has drawn enormous attention as cathode material for aqueous zinc-ion batteries (AZIBs). However, the fragile open-framework and the sluggish Zn2+ migration due to the strong electrostatic interaction between Zn2+ and cathode electrode hinder the development of AZIBs. Here, an effective dual-cations intercalation strategy is employed based on synergistic effect of Mn2+ and Zn2+, which introduces guest species with robust layered construction and weak electrostatic interaction in the V2O5 bulk. Consequently, the (Mn0.13Zn0.03)V2O5 (abbreviated to MZVO) electrode exhibits a high reversible capacity of 463mA h g-1 at 0.1 A g-1, a high cycling stability (94% of capacity retention after 1000 cycles at 10 A g-1) and superior rate performance of 256 mAh g-1 at 20 A g-1. The outstanding performance of MZVO cathode is attributed to the Mn2+-induced fast migration of Zn2+ transfer and Zn2+-induced high structural stability conducted by density functional theory (DFT) calculations. The two-phase reaction mechanism of MZVO during Zn2+ (de)interaction is systematically expounded via operando XRD. This study will provide reference for the design of modified layered metal oxides in the future.

Interface Engineering: Enhanced Catalysis Through Precise Control of Metal Nanocluster Transformation.

Atomically precise metal nanoclusters (NCs) have garnered significant interest due to their unique atomic stacking structures, the effect of quantum confinement, and enriched active sites but suffer from thermal- or light-induced poor instability and self-aggregation, together with in situ self-conversion to conventional metal nanoparticles (NPs). How to effectively harness the generic detrimental self-transformation property of metal NCs has so far not garnered immense attention within the realm of catalysis. In this work, we develop a layer-by-layer assembly technology to accurately anchor metal NCs to the metal oxide matrix. Then, the anchoring of metal NCs to metal NPs is triggered by a simple thermal treatment that enables precise control over the interface structure, resulting in a hollow core-shell heterostructure with a metal core (Au, Ag) encapsulated by a metal oxide (CeO2, Fe2O3, SnO2) shell. Benefiting from the synergistic interplay between metal NPs and the metal oxide substrate, such self-assembled metal NPs@metal oxide heterostructures display excellent catalytic activities and stability in the reduction of aromatic nitro compounds. The detailed catalytic mechanism is elucidated. Our work offers fresh impetus for the judicious utilization of the inherent instability of metal NCs for catalytic selective organic transformation.