Bifunctional modification towards LaNiO3/Perovskite interface for enhanced performance in perovskite solar cells.

Ultra-thin p-type nickel oxide films grown by reactive pulsed laser deposition at room temperature: production of a pn heterojunction

Green approaches to nickel oxide nanoparticles: Visible-light-driven photocatalytic degradation of brilliant green, methyl orange dyes and antibiotic ciprofloxacin

Detection of trace levels of volatile organic compounds (VOCs) has widespread applications, including wearable diagnostics, IoTs, and indoor air quality control. Although metal oxide semiconductors (MOS) arguably offer the best sensitivity for a wide range of VOCs, their poor selectivity limits their performance. Here, we demonstrate a machine learning (ML)-based analysis and framework using a single, non-selective MOS sensor made of RF-sputtered nickel oxide thin film with gold contacts, aiming to achieve VOC classification and concentration prediction with a high degree of accuracy (>90%) and eliminate biases. Both time-independent and time-dependent features were evaluated using classifiers and regressors, including ensemble methods, artificial neural networks, and recurrent architectures (LSTMs and GRUs). The features identified as excluding time reference (response, its gradient, and Laplacian) were highly effective for baseline classification, achieving near-ideal accuracies (98%) with ensemble models. On the other hand, the time-dependent features (continuous, discrete, and time-sliced) complement the analysis by capturing dynamic adsorption-desorption kinetics via sequential models, leading to accuracies of 94% and above. Regression analysis techniques enhance the predictive capabilities of ensemble and neural approaches, yielding higher R2 values and lower RMSE. Thus, the methods adopted in this work highlight the complementary approach of ML-based modeling with that of material innovation to achieve an important performance metric, namely, selectivity of MOS-based sensors, as a way forward for scalable, real-time VOC monitoring in a complex background of other gases. This approach is highly scalable for other toxic gases, pollutants, and biomarkers for relevant applications.

Nickel oxide (NiOx) is among the most widely used hole-transport materials (HTMs) for inverted perovskite solar cells (PSCs), yet its substantial surface defects compromise the device's performance and long-term stability. Despite the development of various surface engineering strategies, the underlying mechanism governing interfacial dynamics is incompletely understood. Herein, we systematically investigate the structural roles of molecular passivators in tailoring NiOx properties, with a focus on elucidating the distinct mechanisms of two structurally analogous modifiers: the polymer polyvinylpyrrolidone (PVP) and the small-molecule N-methylpyrrolidone (NMP). The results demonstrate that the pronounced steric hindrance arising from the long polymer chains of PVP constructs a physical barrier, which detrimentally impacts charge transport and perovskite crystallization. Conversely, NMP capitalizes on its small molecular size and chemical reactivity to achieve directional selective passivation. This chemical modification not only effectively optimizes interfacial properties but also facilitates the crystallization of perovskite films. As a result, the NMP-modified PSCs achieve a power conversion efficiency (PCE) of 20.89%, in contrast to 18.52% for their PVP-modified counterparts. Notably, the unencapsulated NMP-modified device retains 93% of its initial efficiency following 1800 h of storage at 25 °C under a nitrogen atmosphere. This work sheds light on the intrinsic correlation between molecular structure and device performance, thereby offering valuable guidance for further optimization of both the efficiency and long-term stability of PSCs.

Electro-chemo-mechanical coupling failure severely deteriorates the cycling performance of LiNi0.95Co0.02Mn0.03O2 (NCM95), which results from the inhomogeneous lithium-ion distribution at high charge states, coupled with lattice mismatch in drastic phase transformation. To mitigate this challenge, in this work, an in-situ R m‑type disordered phase was induced by interfacial lithium and oxygen vacancies, exhibiting excellent dynamic lattice matching with the underlying layered framework of NCM95. Crucially, differing from the previously reported inert NiO rock salt, the optimal disordered phase possesses redox activity and undergoes thermodynamically driven delithiation reconstruction process. The reconstructed disordered phase homogenizes the lithium-ion distribution and mitigates deep delithiation along with drastic H2-H3 phase transition to promote structural integrity of NCM95. Concurrently, the electrode/electrolyte interface is stabilized by lowering the nickel oxidation state and inhibiting gradual defect formation within the layered lattice. As a result of the structural stability effect, the modified NCM95 exhibits a capacity retention of 99% after 100 cycles at 50 mA g-1, 80% after 400 cycles at 250 mA g-1, and 83% after 900 cycles in all-solid-state battery system. This work clarifies the "double-edged" nature of cation disorder and provides a structurally stable, lattice-matched interface design scheme for ultrahigh nickel content layered cathodes.

Solar-blind ultraviolet (SBUV) photodetection is critically demanded in military and civil fields thanks to its near-zero background radiation. Gallium oxide (Ga2O3) emerges as an ideal wide-bandgap semiconductor for SBUV and power devices thanks to its suitable bandgap and compatibility with substrates. Up to now, the lack of stable p-type Ga2O3 has become a bottleneck, restricting its application. Consequently, p–n heterojunction formation is one possible solution, where p-type nickel oxide appears as a promising p-type semiconductor. Here, we employ mist chemical vapor deposition technology to demonstrate epitaxial integration of single-crystal α-Ga2O3/NiO heterojunctions on c-plane sapphire, featuring a distinct interface with an epitaxial relationship of α-Al2O3(0006) || α-Ga2O3(0006) || NiO(111). The as-grown Li+-doped NiO film shows a high hole mobility (88.32 cm2/V s) and low resistivity (0.09 Ω cm) and exhibits a type-II band alignment with α-Ga2O3, consequently enabling efficient carrier separation. The fabricated α-Ga2O3/NiO p–n junction photodetector exhibits rectification effects and self-powered detection capability, achieving high-performance UV detection with a responsivity of 43.86 A/W, detectivity of 1.64 × 1012 Jones, rejection ratio of 177.3, and fast response (17/16 ms). This work demonstrates a low-cost epitaxial approach to realize high-quality α-Ga2O3/NiO p–n heterojunction integration for fast UV detection applications.

Computation in biological neural circuits arises from the interplay of nonlinear temporal responses and spatially distributed dynamic network interactions. Replicating this richness in hardware has remained challenging, as most neuromorphic devices emulate only isolated neuron- or synapse-like functions. Here we introduce an integrated neuromorphic computing platform in which both nonlinear spatiotemporal processing and programmable memory are realized within a single perovskite nickelate material system. By engineering symmetric and asymmetric hydrogenated NdNiO3 junction devices on the same wafer, we combine ultrafast, proton-mediated transient dynamics with stable multilevel resistance states. Networks of symmetric NdNiO3 junctions exhibit emergent spatial interactions mediated by proton redistribution, while each node simultaneously provides short-term temporal memory, enabling nanosecond-scale operation with an energy cost of ~0.2 nJ per input. When interfaced with asymmetric output units serving as reconfigurable long-term weights, these networks allow both feature transformation and linear classification in the same material system. Leveraging these emergent interactions, the platform enables real-time pattern recognition and achieves high accuracy in spoken digit classification and early seizure detection, outperforming temporal-only or uncoupled architectures. These results position protonic nickelates as a compact, energy-efficient, CMOS-compatible platform that integrates processing and memory for scalable intelligent hardware.

Direct borohydride fuel cells (DBFCs) are promising for high-energy-density power sources, but their practical application is limited by slow borohydride oxidation reaction (BOR) kinetics, competing hydrogen evolution reaction (HER), and insufficient catalyst durability. In this work, a succulent-like hierarchical Ni/NiCo catalytic electrode has been reported, which was prepared by a two-step constant-current deposition through combining electronic modulation strategy and structural engineering. In situ attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), COMSOL simulations, and electrochemistry testing demonstrate that Co incorporation induces tensile lattice strain and modulates the electronic structure of a Ni-based catalyst, while the hierarchical architecture with defect-rich features maximizes active site exposure, accelerates mass transport, and suppresses the oxidation of nickel and the competitive HER, thus enhancing the direct borohydride oxidation. Consequently, the Ni/NiCo electrode delivers outstanding catalytic activity, stability, and selectivity to BOR. Moreover, when used as the anode, DBFC can achieve an open-circuit voltage of 1.91 V and a peak power density of 413 mW cm-2 and operate stably for 36 h under 50 mA·cm-2 at room temperature. This work establishes a cost-effective route for the development of next-generation high-performance DBFC anode catalysts and also enriches preliminary understanding about the electronic regulation and hierarchical architecture of catalysts.

The growing demand for strategically important metals, coupled with the depletion of high-quality ores, has highlighted the potential of man-made waste as a secondary source of vanadium and molybdenum. This study investigates the alkaline leaching of technogenic vanadium-containing waste (filter cake) using sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) as an oxidiser. Chemical and X-ray fluorescence analyses confirmed significant contents of vanadium (3.44%), molybdenum (0.75%), and other valuable metals, indicating the feasibility of complex metal recovery. An experimental design based on the response surface methodology (RSM) and a central composite plan was employed to evaluate the effects of leaching time, reagent concentration, pH, and temperature on metal extraction. Quadratic regression models were constructed and validated using analysis of variance (ANOVA), demonstrating high adequacy (vanadium: F = 9.55, p < 0.001; molybdenum: F = 9.84, p < 0.01). Under optimal conditions, extraction efficiencies were 88–89% for vanadium and 80–82% for molybdenum, increasing to 89–93% and 82–83%, respectively, with the addition of NaOCl. X-ray phase analysis revealed the formation of stable aluminium and nickel oxide phases, which partially limited extraction and explained deviations from predicted values. The results demonstrate that combining alkaline leaching with an oxidiser and statistical modelling enables effective optimisation of multicomponent waste processing, enhancing metal recovery and reducing environmental impacts, thereby providing a basis for resource-efficient, environmentally friendly metallurgical technologies in Kazakhstan.

Designing cost-effective and durable bifunctional electrocatalysts is critical for efficient water electrolysis and sustainable hydrogen production. Herein, we report an interfacial engineering approach to construct layered iron-cobalt hydroxides (Fe1-xCox(OH)2@S1, where "S1" represents the molar ratio of Fe:Co (3:1) and x = 0.25) with optimized Fe-O-Co active centers. The engineered heterointerface promotes charge redistribution and accelerates reaction kinetics, thereby reducing adsorption energy barriers for the key intermediates. The Fe1-xCox(OH)2@S1 electrode achieves low overpotentials of ∼0.270 V for oxygen evolution and ∼0.192 V for hydrogen evolution at 10 mA cm-2, alongside a turnover frequency of 0.165 s-1 and high mass activity (∼11.2 A g-1). When used as both an anode and cathode, the symmetric electrolyzer operates at only 1.61 V to deliver 10 mA cm-2, rivaling the RuO2∥Pt/C benchmarks. These results highlight the crucial role of Fe-Co-Ni interfacial coupling in modulating electronic structures and catalytic energetics. This work offers a generalizable strategy for developing advanced multimetal hydroxide catalysts toward highly efficient alkaline water electrolysis.

Nickel oxide nanosheets grown on amorphous and porous zinc-tin-oxide microcubes as heterojunctions for effective sensing of triethylamine gas.

Comprehensive investigation on nickel oxide (NiO) thin film fabrication mechanism by electrostatic spray deposition (ESD) technique and annealing temperature effect on NiO/ZnO diodes

Enhanced electrochemical degradation of microcystin-lysine-arginine (MC-LR) using novel nickel oxide anodes in real water matrices.

Mining poses significant and persistent threats to freshwater ecosystems, with impacts often enduring long after operations cease. Growing concerns suggest that the expansion of mining to meet global mineral demands for decarbonization may amplify these cumulative risks to freshwater biodiversity. However, the location and extent of potential conflict hotspots remain poorly understood, hampering our ability to meet international conservation targets. Here, we map areas of potential conflict between freshwater conservation priority areas and global mining activities. Using a spatial modeling approach, we trace potential downstream contamination and quantify the extent of affected river reaches within conservation priority areas. Our analysis reveals that mining may pollute up to 1.8 million km of downstream rivers (5% of the global total), over 18% of which lies within conservation priority areas. Gold mining is associated with the largest extent of potentially contaminated rivers, and its widespread reliance on unregulated small-scale artisanal practices can lead to disproportionately severe impacts on freshwater biodiversity in affected areas. Furthermore, rivers potentially affected by coal mining far exceed those linked to the share of key energy transition minerals needed for clean energy technologies (cobalt, copper, graphite, lithium, nickel, and rare earth elements). Effectively safeguarding and restoring freshwater ecosystems will require conservation and regulatory frameworks that address downstream mining impacts, especially in the context of future mineral expansion.

Effects of nickel oxide nanoparticles and minor temperature changes on cytotoxic, antioxidant, reproductive, and genotoxic responses in gonadal Oncorhynchus mykiss cells.

Reduced graphene Oxide–Nickel cobalt zinc metal organic framework composites for supercapacitor applications

ABSTRACT Phytochemistry‐mediated nanoparticle synthesis offers an eco‐friendly and sustainable approach for biomedical applications. In this novel study, nickel oxide nanoparticles (NiONPs) were successfully biosynthesized using the root extract of Argemone mexicana (L.). The synthesized NiONPs exhibited an absorption peak at 330 nm in the UV–vis spectrum, while FTIR analysis confirmed the presence of various functional groups responsible for nanoparticle stabilization. XRD analysis revealed a crystalline structure, and FESEM and HR‐TEM micrographs indicated spherical morphology and an average particle size of 18.5 nm, with elemental nickel (72.3 wt%) confirmed by EDX and the zeta potential analyses of ‐12.5 mV, consistent with colloidal stability. The biosynthesized NiONPs displayed potent antioxidant activity with the maximum ABTS (72.53 ± 1.91%) radical scavenging. Antibacterial evaluation demonstrated broad‐spectrum activity, with Escherichia coli showing the highest inhibition zone (17.38 ± 1.42 mm). Anti‐inflammatory activity assays revealed COX‐2 inhibition of 76.39 ± 2.17%, respectively. Furthermore, cytotoxicity studies against MCF‐7 cells, using the MTT assay, showed a significant reduction in cell viability (36.59 ± 1.73%) at 100 µg/mL. These findings indicate that A. mexicana ‐mediated NiONPs exhibit potent antioxidant, antibacterial, anti‐inflammatory, and anticancer properties, suggesting their potential as therapeutic nanomaterials.

Nickel oxide (NiOx) is a promising hole-transport material widely used in inverted perovskite solar cells (PSCs) due to its high carrier mobility and good transparency. However, light-induced degradation of the NiOx-perovskite heterojunction remains the main factor limiting the long-term operational lifetime of these solar cells. In this study, a traditional p-type organic dye (TPA-CN), commonly used in p-type NiOx dye-sensitized solar cells, is employed as self-assembled monolayer (SAM) molecules for interface modification between NiOx and perovskite in inverted PSCs. In TPA-CN, carboxyl anchoring groups passivate Ni3 + defects on NiOx and enhance hole extraction, while the cyano group passivates undercoordinated Pb2 + in the buried perovskite layer, lowering trap density. Furthermore, TPA-CN functions as an interfacial bridge, boosting charge transfer from the perovskite to NiOx, which improves both the performance and stability of perovskite solar cells (PSCs). As a result, TPA-CN-modified devices achieve a peak power conversion efficiency (PCE) of 25.54%, compared to 21.80% for unmodified control devices. Notably, unencapsulated devices maintain 89.2% of their initial PCE after 1800 h under ambient conditions (ISOS-D-1) and 95.3% after 500 h of continuous 1-sun illumination. This research presents an effective molecular design approach for developing high-performance inverted PSCs using charge-selective materials.

This research aims to test the characterisation of the barium ferrite copper nickel oxide (BaFe12-2xCuxNixO19) sample as a microwave absorbing material that will be applied to radio detection and ranging (Radar). The materials used in the synthesis process are barium carbonate (BaCO3), iron oxide (Fe3O4), copper sulfate (CuSO4), and nickel(II)chloride hexahydrate (NiCl2.6H2O) powders, while the solutions are 12 M hydrochloric acid (HCl), ammonium hydroxide (NH4OH), and distilled water, which has been synthesised using the coprecipitation method with varying ion doping x = 0.0, 0.4, 0.8, and 1.0%, which is calcined at temperatures of 200, 600, and 1,000°C. The samples were then tested for characteristics through four stages of testing, namely X-ray diffraction (XRD), Fourier transform independent infrared spectroscopy (FTIR), transmission electron microscope (TEM), vibrating sample magnetometre (VSM), and vector network analyser (VNA). The test results using FTIR produced peaks at wave numbers 584-1639 cm⁻¹, which indicated the presence of Ba-O, Fe-O, Cu-O, and Ni-O functional groups. This indicates that the materials used in the synthesis process reacted or were present in the final sample. The test results using TEM with a sample of x = 1.0% and a calcination temperature of 1,000°C show that the resulting particles are hexagonal with a size of 50 nm. Tests using VSM show that the low coercivity value decreases, and the magnetic remanence and magnetic saturation values ​​increase along with the use of ion doping and calcination temperature. The sample underwent a change from hard magnetic to soft magnetic based on the results of a decrease in the coercivity value and has the potential to become a microwave-absorbing material. The final test results using VNA produced a reflection loss value of -22.456 dB with an absorption percentage of 99.62%. The maximum electrical conductivity produced is 1.20305 at a temperature of 1,000°C. According to the indicators, the sample meets the criteria to be applied as a microwave-absorbing material, namely having a nanoparticle size, being soft magnetic, and being included as a semiconductor material.