Neuromorphic Computing with Emerging Antiferromagnetic Ordering in Spin-Orbit Torque Devices.

Field-free switching (FFS) and spin-orbit torque (SOT)-based neuromorphic characteristics were realized in a W/Pt/Co/NiO/Pt heterostructure with a perpendicular exchange bias (HEB) for brain-inspired neuromorphic computing (NC). Experimental results using NiO-based SOT devices guided the development of fully spin-based artificial synapses and sigmoidal neurons for implementation in a three-layer artificial neural network. This system achieved impressive accuracies of 91-96% when applied to the Modified National Institute of Standards and Technology (MNIST) image data set and 78.85-81.25% when applied to Fashion MNIST images, due presumably to the emergence of robust NiO antiferromagnetic (AFM) ordering. The emergence of AFM ordering favored the FFS with an enhanced HEB, which suppressed the memristivity and reduced the recognition accuracy. This indicates a trade-off between the requirements for solid-state memory and those required for brain-inspired NC devices. Nonetheless, our findings revealed opportunities by which the two technologies could be aligned via controllable exchange coupling.

Novel Gel method MXene-Supported Dual-Site PtNi-NiO for Electrocatalytic Water Reduction and Urea Oxidation.

Compared to the traditional oxygen evolution reaction (OER), the urea oxidation reaction (UOR) generally exhibits a lower overpotential during the electrolytic process, which is conducive to the hydrogen evolution reaction (HER) at the cathode. The superior structure and abundant sites play a crucial role in promoting the adsorption and cleavage of urea molecules. Therefore, this paper introduces a simple metal cation-induced gelation method to prepare an electrocatalyst with PtNi alloy-NiO dual sites supported on Ti3C2Tx, which simultaneously exhibits excellent UOR and HER performance. PtNi-NiOx/Ti3C2Tx demonstrates good catalytic activity for the urea oxidation reaction, requiring only 1.364 V (overpotential of 0.994 V) to achieve a current density of 100 mA cm-2 in UOR, and also exhibits remarkable catalytic activity in the hydrogen evolution reaction, with PtNi-NiOx/Ti3C2Tx achieving a current density of 10 mA cm-2 in HER with only 24 mV of overpotential. In the UOR//HER two-electrode electrolysis cell, it requires only 1.361 and 1.538 V to reach current densities of 10 and 100 mA cm-2, respectively. According to density functional theory (DFT) calculations, the dual active sites can intelligently adsorb the electron-donating/electron-withdrawing groups in urea molecules, activate chemical bonds, and thereby initiate urea decomposition.

Interfacial Engineering of Nickel Oxide-Perovskite Interface with Amino Acid Complexed NiO to Improve Perovskite Solar Cell Performance.

The interface between NiO and perovskite in inverted perovskite solar cells (PSCs) is a major factor that can limit device performance due to defects and inappropriate redox reactions, which cause nonradiative recombination and decrease in open-circuit voltage (VOC). In the present study, a novel approach is used for the first time, where an amino acid (glycine (Gly), alanine (Ala), and aminobutyric acid (ABA))-complexed NiO are used as interface modifiers to eliminate defect sites and hydroxyl groups from the surface of NiO. The Ala-complexed NiO suppresses interfacial non-radiative recombination, improves the perovskite layer quality and better energy band alignment with the perovskite, resulting in improved charge transfer and reduced recombination. The incorporation of the Ala-complexed NiO leads to a PCE of 20.27% with enhanced stability under the conditions of ambient air, light soaking, and heating to 85 °C, as it retains over 82%, 85%, and 61% of its initial PCE after 1000, 500, and 350 h, respectively. The low-temperature technique also leads to the fabrication of a NiO thin film that is suitable for flexible PSCs. The Ala-complexed NiO is fabricated on the flexible substrate and achieved 17.12% efficiency while retaining 71% of initial PCE after 5,000 bending.

SiC@NiO Core-Shell Nanowire Networks-Based Optoelectronic Synapses for Neuromorphic Computing and Visual Systems at High Temperature.

1D nanowire networks, sharing similarities of structure, information transfer, and computation with biological neural networks, have emerged as a promising platform for neuromorphic systems. Based on brain-like structures of 1D nanowire networks, neuromorphic synaptic devices can overcome the von Neumann bottleneck, achieving intelligent high-efficient sensing and computing function with high information processing rates and low power consumption. Here, high-temperature neuromorphic synaptic devices based on SiC@NiO core-shell nanowire networks optoelectronic memristors (NNOMs) are developed. Experimental results demonstrate that NNOMs attain synaptic short/long-term plasticity and modulation plasticity under both electrical and optical stimulation, and exhibit advanced functions such as short/long-term memory and "learning-forgetting-relearning" under optical stimulation at both room temperature and 200 °C. Based on the advanced functions under light stimulus, the constructed 5 × 3 optoelectronic synaptic array devices exhibit a stable visual memory function up to 200 °C, which can be utilized to develop artificial visual systems. Additionally, when exposed to multiple electronic or optical stimuli, the NNOMs effectively replicate the principles of Pavlovian classical conditioning, achieving visual heterologous synaptic functionality and refining neural networks. Overall, with abundant synaptic characteristics and high-temperature thermal stability, these neuromorphic synaptic devices offer a promising route for advancing neuromorphic computing and visual systems.

Phosphorus-Doped Nickel Oxide Micro-Supercapacitor: Unleashing the Power of Energy Storage for Miniaturized Electronic Devices.

For an uninterrupted self-powered network, the requirement of miniaturized energy storage device is of utmost importance. This study explores the potential utilization of phosphorus-doped nickel oxide (P-NiO) to design highly efficient durable micro-supercapacitors. The introduction of P as a dopant serves to enhance the electrical conductivity of bare NiO, leading to 11-fold augmentation in volumetric capacitance to 841.92 Fcm-3 followed by significant enhancement of energy and power density from 6.71 to 42.096 mWhcm-3 and 0.47 to 1.046 Wcm-3, respectively. Theoretical calculations used to determine the adsorption energy of OH- ions, revealing higher in case of bare NiO (1.52 eV) as compared to phosphorus-doped NiO (0.64 eV) leading to high electrochemical energy storage performance. The as-designed micro-supercapacitor (MSC) device demonstrates a facile integration with the photovoltaic system for renewable energy storage and smooth transfer to external loads for enlightening the blue LED for ≈1 min. The choice of P-NiO/Ni not only contributes to cost reduction but also ensures minimal lattice mismatch at the interface facilitating high durability up to 15 K cycles along with capacitive retention of ≈100% and coulombic efficiency of 93%. Thus, the heterostructure unveils the possibilities of exploring miniaturized energy storage devices for portable electronics.

Studies of carrier transport mechanism in NiO/Ag/NiO transparent conducting electrode/ZnO metal-semiconductor-metal photodetectors.

Oxide/metal/oxide multilayers as a transparent conducting electrode (TCE) have been developed to replace metals due to their high transparency and low sheet resistance. Nickel oxide (NiO) film with a high work function was used as an oxide to form NiO/Ag/NiO (NAN) TCE, therefore a high barrier height between NAN/zinc oxide (ZnO) interface. In the study, NAN TCE was deposited on ZnO surface to fabricate metal-semiconductor-metal (MSM) photodetectors (PDs) and study its carrier transport mechanism. The NAN TCE has a low sheet resistance of 6.5 Ω/sq. and transmittance more than 40% in a 300-1000 nm wavelength range. Such issues result in the figure-of-merit is higher (2.3 × 10-4Ω-1) than that (2.5 × 10-7Ω-1) of pure single NiO thin film. As compared to the conventional Au/ZnO MSM-PDs, the NAN/ZnO MSM-PDs demonstrates a lower leakage current as a result of Ni atoms diffusing into ZnO and passivating the defects. Due to the high work function of NiO, the NAN/ZnO interface exhibits a barrier height as high as 0.91 eV. The Au/ZnO MSM-PDs reveals only one carrier conduction of ohmic due to the electrons tunnel form Au into ZnO through the surface defects. In contrast, two distinct carrier transport mechanisms were observed in the NAN/ZnO MSM-PDs. At low-voltage forV⩽0.64 V, ohmic conduction dominates and the electrons inject from NAN to ZnO, trapped by the defect states of ZnO. At high-voltage for V⩾0.64 V, the trapped electrons acquire enough energy and emit from trap to conduction band, entering Poole-Frankel emission transport.

NiO/MnO2coated on carbon felt as an electrode material for supercapacitor applications.

Transition metal oxides have demonstrated excellent capability for charge storage when used in supercapacitor electrodes. This study undertook the hydrothermal synthesis of bimetallic nickel and manganese oxide (NiO/MnO2) on a carbon-felt (CF) substrate. NiO/MnO2/CF electrode was characterized and examined in a three-electrode system in a potassium hydroxide electrolyte. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge analyses revealed Faradaic behavior during charge storage, a specific capacity of 1627 F/g, and a stability of 96.8% after 5000 consecutive charge-discharge cycles. Subsequent investigations were conducted in a two-electrode system for constructing a symmetrical supercapacitor using the NiO/MnO2/CF electrode. The energy and power densities were determined as 43Wh/kg and 559 W/kg. Additionally, the stability of the constructed supercapacitor device was examined over 5000 consecutive cycles, verifying a 92% stability through charge-discharge cycles. Finally, the fabricated supercapacitor was utilized to power an LED lamp, successfully maintaining the illumination for 53 seconds. .

Application of N-doped NiCo2O4/NiO/Co3O4composites rich in oxygen vacancies in electromagnetic wave absorption.

In this work, N-doped and oxygen vacancy-rich NiCo2O4/NiO/Co3O4composites are synthesized by the direct calcination method. Noticeably, by changing the additive concentrations of urea dissolved in DMF (N-N dimethylformamide), the electromagnetic wave (EMW) absorption abilities of NiCo2O4/NiO/Co3O4composite effectively. A maximum reflection loss (RLmax) value at 12.94 GHz for a 2.8 mm thick sheet is -29.76 dB, while its effective absorption bandwidth (RL < -10 dB) reaches 4.21 GHz. In-depth research of possible mechanisms of EMW absorption enhancement. Owing to its simple preparation method and superb EMW absorption properties, the NiCo2O4/NiO/Co3O4composites have a chance to be suitable candidates for high-property EMW absorbers.

Enhanced photocatalytic degradation of polycyclic aromatic hydrocarbons (PAHs) Using NiO nanoparticles.

The oncogenic and genetic properties of anthracene, a member of the polycyclic aromatic hydrocarbons (PAHs) family, pose a significant health threat to humans. This study aims to investigate the photocatalytic decomposition of anthracene under various conditions, such as different concentrations of PAHs, varying amounts of NiO (nickel oxide) nanoparticles, and different pH levels under ultraviolet light and sunlight. The synthesized NiO nanoparticles showed surface plasma resonance at 230 and 360 nm, while XRD and SEM analysis confirmed the nanoparticles were cubic crystalline in structure with sizes ranging between 37 and 126 nm. NiO nanoparticles exhibited 79% degradation of pyrene at 2 µg/mL of anthracene within 60 min of treatment. NiO at 10 µg/mL concentration showed significant adsorption of 57%, while the adsorption method worked efficiently (72%) at 5 pH. Photocatalytic degradation was confirmed by isotherm and kinetic studies through monolayer adsorption and pseudo-first-order kinetics. Further, the absorption process was confirmed by performing GC-MS analysis of the NiO nanoparticles. On the other hand, NiO nanoparticles showed antimicrobial activity against Gram negative and Gram-positive bacteria. Therefore, the present work is one of its kind proving the dual application of NiO nanoparticles, which makes them suitable candidates for bioremediation by treating PAHs and killing pathogenic bacteria.

Construction of La1-xSrxNiO3/g-C3N4 type-Z heterojunctions with enhanced visible-light photocatalytic degradation of organic pollutants.

Lanthanum nickelate (LaNiO3), known for its high visible-light absorption, is a promising photocatalyst for water purification. However, the low conduction band position and high photogenerated carrier complexation rate of pure LaNiO3 limit its photocatalytic activity. To address this issue, we investigated the synergistic effects of doping and constructing heterojunctions. A La0.9Sr0.1NiO3 (20%)/g-C3N4 (L2CN8) heterojunction was successfully created. In addition, various characterisation techniques were then employed to analyse the structure-performance relationships of these heterojunction photocatalysts in degrading organic dyes. Results revealed that at a 10% Sr doping level, the oxygen vacancy content was 0.68, which is significantly higher than that of LaNiO3 (0.05). The increased number of oxygen vacancies enhanced the electron capture ability and improved the separation efficiency of photogenerated carriers. Furthermore, the optimised L2CN8 (20 mg) achieved 81.2% and 73.8% removal of methylene blue (50.0 mL, 10 mg L-1) and tetracycline (50.0 mL, 10 mg L-1) under simulated visible-light irradiation (λ > 420 nm). Furthermore, an active species capture experiment confirmed the significant role of superoxide radicals (·O2-) in the degradation process. Based on these experimental findings, we proposed a rational Z-type charge transfer mechanism. This study holds great importance for water pollution control and environmental protection.

Light-harvesting iridium (III) complex-sensitized NiO photocathode for photoelectrochemical bioanalysis.

A novel iridium (III) complex bearing boron dipyrromethene (Bodipy) as the light-harvesting antenna has been synthesized and is firstly employed as photosensitizer to assemble a dye-sensitized NiO photocathode. The assembled photocathode exhibits significantly improved photoelectrochemical (PEC) performance. Integrating the prepared photocathode with hybridization chain reaction (HCR)--based signal amplification strategy, a cathodic PEC biosensor is proposed for the detection of microRNA-133a (miRNA-133a). In the presence of the target, HCR is triggered to form long duplex concatamers on the photocathode, which allows numerous manganese porphyrins (MnPP) to bind in the dsDNA groove. With the help of H2O2, MnPP with peroxidase-like activity catalyzes 4--chloro-1-naphthol (4-CN) to produce benzo--4--chlorohexadienone (4-CD) precipitate on the electrode, leading to a significant decrease of photocurrent signal. The decreased photocurrent correlates linearly with the target concentration from 0.1 fM to 1 nM with a detection limit of 66.2 aM (S/N = 3). The proposed PEC strategy exhibits delightful selectivity, reproducibility and stability.

Dye-sensitized NiO photocathode sensor based on signal-sensitive change strategy for MC-LR detection.

A novel photoelectrochemical (PEC) sensor for the detection of microcystic toxins (MC-LR) was developed on the basis of signal-sensitive change strategy. NiO nanoarray as a basic photoactive material was grown directly on the ITO glass electrode via calcination after hydrothermal reaction, while dye N719 was used to sensitize the electrode for enhancing visible light absorption, and the first signal-on stage was obtained. In the meantime, p-type Cu2O was applied as the signal probe attached to probe DNA (DNA2) to improve the sensitivity, and the second "signal-on" stage appeared because of its synergistic effect with NiO nanoarrays. The PEC signal decreases after the target analyte MC-LR is modified on the electrode due to the stronger affinity between MC-LR and its complementary aptamer DNA; part of the Cu2O-DNA2 will dissociate from the electrode. This sensitive signal change strategy allows the detection limit of the MC-LR sensor to be as low as 1.7 pM, which offers an optional method for the sensitive and selective detection of other target molecules, with potential applications in environmental monitoring and toxin determination.

Green NiO nanoparticle-integrated PVA-alginate hydrogel: potent nanocatalyst for efficient reduction of anthropogenic water pollutants.

Hydrogel nanocatalyst composed of nickel oxide (NiO) nanoparticles embedded in PVA-alginate hydrogels were potentially explored toward the reduction of anthropogenic water pollutants. The NiO nanoparticles was accomplished via green method using waste pineapple peel extract. The formation of the nanoparticles was affirmed from different analytical techniques such as UV-Vis, FTIR, XRD, TGA, FESEM, and EDS. Spherical NiO nanoparticles were obtained having an average size of 11.5 nm. The nano NiO were then integrated into PVA-alginate hydrogel matrix forming a nanocomposite hydrogel (PVALg@ NiO). The integration of nano NiO rendered an improved thermal stability to the parent hydrogel. The PVALg@ NiO hydrogel was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP), potassium hexacyanoferrate (III), rhodamine B (RhB), methyl orange (MO), and malachite green (MG) in the presence of a reducing agent, i.e., NaBH4. Under optimized conditions, the reduction reactions were completed by 4.0 min and 3.0 min for 4-NP and potassium hexacyanoferrate (III), respectively, and the rate constant was estimated to be 1.14 min-1 and 2.15 min-1. The rate of reduction was found to be faster for the dyes and the respective rate constants were be 0.17 s-1 for RhB, MG and 0.05 s-1 for MO. The PVALg@ NiO hydrogel nanocatalyst demonstrated a recyclability of four runs without any perceptible diminution in its catalytic mettle. The efficacy of the PVALg@ NiO hydrogel nanocatalyst was further examined for the reduction of dyes in real water samples collected from different sources and the results affirm its high catalytic potential. Thus, this study paves the path for the development of a sustainable hydrogel nanocatalyst for reduction of hazardous pollutants in wastewater treatment.

Facile green synthesis of a novel NiO and its catalytic effect on methylene blue photocatalytic reduction and sodium borohydride hydrolysis.

NiO nanoparticles were synthesized from pine cone extract by green synthesis method, which is a simple, cost-effective, environmentally friendly and sustainable method. The particle size of NiO nanoparticles was determined to be in the range of 10-25 nm by X-diffraction differential and transmission electron microscope analysis, and the bandgap energy of NiO nanoparticles was determined to be 2.66 eV. The catalytic effect of NiO nanoparticles in both microwave-assisted sodium borohydride hydrolysis and photocatalytic reduction of methylene blue was examined and it was determined that they had a high catalytic effect in both applications. It was determined that the hydrogen production rate in sodium borohydride hydrolysis was 1135 mL/g/min. The activation energy of sodium borohydride hydrolysis is 29.69 kJ/mol and 29.59 kJ/mol for the nth-order and Langmuir Hinshelwood kinetic models, respectively. In the photocatalytic reduction of methylene blue with NaBH4, it was determined that the reduction did not occur in the absence of a catalyst, but in the presence of the catalyst, the reduction occurred 98% in 3 min. It was determined that NiO nanoparticles were used five times in the photocatalytic reduction of methylene blue and the reduction efficiency for the fifth time was 93%. It was determined that the photocatalytic reduction of methylene blue was pseudo-first order and the rate constant was 1.63 s-1. It was determined that NiO nanoparticles synthesized by the environmentally friendly green synthesis method can be used as catalysts for two different applications.

NiO nanoparticles were synthesized from pinecone extract in a simple, cost-effective, and green method. The synthesized NiO nanoparticles were characterized using various characterization techniques. NiO nanoparticles have high activity both in the photocatalytic reduction of methylene blue and in the hydrolysis of sodium borohydride, and they are catalysts with high activity in two different applications. Photocatalytic reduction of methylene blue with uncatalyzed NaBH₄ was not achieved and was completed in 3 min in the presence of NiO nanoparticle catalyst. It was determined that the hydrogen production rate in sodium borohydride hydrolysis was 1135 mL/g^/min. NiO nanoparticle catalysts have low activation energy for sodium borohydride hydrolysis.

Thermophysical Investigation of Multiform NiO Nanowalls@carbon Foam/1-Octadecanol Composite Phase Change Materials for Thermal Management.

Multiform NiO nanowalls with a high specific surface area were constructed in situ on carbon foam (CF) to construct NiO@CF/OD composite phase change materials (CPCMs). The synthesis mechanism, microstructures, thermal management capability, and photothermal conversion of NiO@CF/OD CPCMs were systematically studied. Additionally, the collaborative enhancement effects of CF and multiform NiO nanowalls on the thermal properties of OD PCMs were also investigated. NiO@CF not only maintains the porous 3D network structure of CF, but also effectively prevents the aggregation of NiO nanosheets. The chemical structures of NiO@CF/OD CPCMs were analyzed using XRD and FTIR spectroscopy. When combined with CF and NiO nanosheets, OD has high compatibility with NiO@CF. The thermal conductivity of NiO@CF/OD-L CPCMs was 1.12 W/m·K, which is 366.7% higher than that of OD. The improvement in thermal conductivity of CPCMs was theoretically analyzed according to the Debye model. NiO@CF/OD-L CPCMs have a photothermal conversion efficiency up to 77.6%. This article provided a theoretical basis for the optimal design and performance prediction of thermal storage materials and systems.

Novel and Extremely Sensitive NiAl2O4-NiO Nanostructures on an ITO Sensing Electrode for Enhanced Detection of Ascorbic Acid.

The current study focused on the design of an extremely sensitive electrochemical sensor of ascorbic acid based on a mixture of NiAl2O4-NiO nanoparticles that, produced in a single step using the sol-gel method, on an ITO electrode. This new sensing platform is useful for the detection of ascorbic acid with a wide range of concentrations extending from the attomolar to the molar. SEM micrographs show the porous structure of the NiAl2O4-NiO sample, with a high specific surface area, which is beneficial for the catalytic performance of the nanocomposite. An XRD diffractogram confirmed the existence of two phases, NiAl2O4 and NiO, both corresponding to the face-centred cubic crystal structure. The performances of the modified electrode, as a biomolecule, in the detection of ascorbic acid was evaluated electrochemically by cyclic voltammetry and chronoamperometry. The sensor exhibited a sensitive electrocatalytic response at a working potential of E = +0.3 V vs. Ag/Ag Cl, reaching a steady-state current within 30 s after each addition of ascorbic acid solution with a wide dynamic range of concentrations extending from attolevels (10-18 M) to molar (10 mM) and limits of detection and quantification of 1.2 × 10-18 M and 3.96 × 10-18 M, respectively. This detection device was tested for the quantification of ascorbic acid in a 500 mg vitamin C commercialized tablet that was not pre-treated.

Enhancement of Ni-NiO-CeO2 Interaction on Ni-CeO2/Al2O3-MgO Catalyst by Ammonia Vapor Diffusion Impregnation for CO2 Reforming of CH4.

Ni-based catalysts have been widely used for the CO2 reforming of methane (CRM) process, but deactivation is their main problem. This study created an alternative electronic Ni-NiO-CeO2 interaction on the surface of 5 wt% Ni-5 wt% CeO2/Al2O3-MgO (5Ni5Ce(xh)/MA) catalysts to enhance catalytic potential simultaneously with coke resistance for the CRM process. The Ni-NiO-CeO2 network was developed on Al2O3-MgO through layered double hydroxide synthesis via our ammonia vapor diffusion impregnation method. The physical properties of the fresh catalysts were analyzed employing FESEM, N2 physisorption, and XRD. The chemical properties on the catalyst surface were analyzed employing H2-TPR, XPS, H2-TPD, CO2-TPD, and O2-TPD. The CRM performances of reduced catalysts were evaluated at 600 °C under ambient pressure. Carbon deposits on spent catalysts were determined quantitatively and qualitatively by TPO, FESEM, and XRD. Compared to 5 wt% Ni-5 wt% CeO2/Al2O3-MgO prepared by the traditional impregnation method, the electronic interaction of the Ni-NiO-CeO2 network with the Al2O3-MgO support was constructed along the time of ammonia diffusion treatment. The electronic interaction in the Ni-NiO-CeO2 nanostructure of the treated catalyst develops surface hydroxyl sites with an efficient pathway of OH* and O* transfer that improves catalytic activities and coke oxidation.

On the Fragmentation of Ni(II) ß-Diketonate-Diamine Complexes as Molecular Precursors for NiO Films: A Theoretical and Experimental Investigation.

NiO-based nanomaterials have attracted considerable interest for different applications, which have stimulated the implementation of various synthetic approaches aimed at modulating their chemico-physical properties. In this regard, their bottom-up preparation starting from suitable precursors plays an important role, although a molecular-level insight into their reactivity remains an open issue to be properly tackled. In the present study, we focused on the fragmentation of Ni(II) diketonate-diamine adducts, of interest as vapor-phase precursors for Ni(II) oxide systems, by combining electrospray ionization mass spectrometry (ESI-MS) with multiple collisional experiments (ESI-MSn) and theoretical calculations. The outcomes of this investigation revealed common features in the fragmentation pattern of the target compounds: (i) in the first fragmentation, the three complexes yield analogous base-peak cations by losing a negatively charged diketonate moiety; in these cations, Ni-O and Ni-N interactions are stronger and the Ni positive charge is lower than in the parent neutral complexes; (ii) the tendency of ligand electronic charge to migrate towards Ni further increases in the subsequent fragmentation, leading to the formation of a tetracoordinated Ni environment featuring an interesting cation-π intramolecular interaction.

Catalytic Hydroconversion of Model Compounds over Ni/NiO@NC Nanoparticles.

The conversion of lignite into aromatic compounds by highly active catalysts is a key strategy for lignite valorization. In this study, Ni/NiO@NC nanocomposites with a high specific surface area and a vesicular structure were successfully prepared via a facile sol-gel method. The Ni/NiO@NC catalysts exhibited excellent catalytic activity for the catalytic hydroconversion (CHC) of benzyloxybenzene (as lignite-related modeling compounds) under mild conditions (120 °C, 1.5 MPa H2, 60 min). The possible mechanism of the catalytic reaction was investigated by analyzing the type and content of CHC reaction products at different temperatures, pressures, and times. More importantly, the magnetic catalyst could be conveniently separated by a magnet after the reaction, and it maintained high catalytic efficiency after six reuses. This study provides an efficient and recyclable catalyst for the cleavage of >CH-O bonds in lignite, thereby offering another way for improved utilization of lignite.

All-Oxide Transparent Photodetector Array for Ultrafast Response through Self-Powered Excitonic Photovoltage Operation.

Can photodetectors be transparent and operate in self-powered mode? Is it possible to achieve invisible electronics, independent of the external power supply system, for on-site applications? Here, a ZnO/NiO heterojunction-based high-functional transparent ultraviolet (UV) photodetector operating in the self-powered photovoltaic mode with outstanding responsivity and detectivity values of 6.9 A W-1 and 8.0 × 1012 Jones, respectively, is reported. The highest IUV /Idark value of 8.9 × 104 is attained at a wavelength of 385 nm, together with a very small dark current value of 9.15 × 10-12 A. A large-scale sputtering method is adopted to deposit the heterostructure of n-ZnO and p-NiO sequentially. This deposition instinctively forms an abrupt junction, resulting in a high-quality heterojunction device. Moreover, developing a ZnO/NiO-heterojunction-based 4 × 5 matrix array with an output photovoltage of 4.5 V is preferred for integrating photodetectors into sensing and imaging systems. This transparent UV photodetector exhibits the fastest photo-response time (83 ns) reported for array configurations, which is achieved using an exciton-induced photovoltage based on a neutral donor-bound exciton. Overall, this study provides a simple method for achieving a high-performance large-scale transparent UV photodetector with a self-powered array configuration.