Nickel Sulfide Research Articles

Theoretical and experimental studies on 2D β-NiS battery-type electrodes for high-performance supercapacitor

Recently, quirky features and eccentric structures of transition metal sulfides have grasped great attention to remove roadblocks and unwrap fresh avenues for electrodes in energy storage devices. Herein, we developed a 2D beta phase nickel sulfide nanosheets (2D β-NiS NSs) electrode with remarkable enhancement in charge storage properties. When served as active electrodes for electrochemical tests, 2D NiS NSs exhibited ultra-high capacitance of 2693 Fg−1 at 1 mVs−1 and specific capacity of 219 mAhg−1 at 1 Ag−1. The symmetric battery type solid-state supercapacitor device comprising 2D β-NiS NSs electrodes exhibits specific capacity of 83.43 mAhg−1at 2 Ag−1 over broad potential range of 0.7V with good cycling performance, and energy and power density of 28.9 Whkg−1 (@ 2 Ag−1) and 21 kWkg−1 (@ 6 Ag−1) respectively. Complementary first-principles density functional theory (DFT) calculations accomplished to explore the electrolyte ion interactions with nickel sulfide nanostructures defining 2D NiS NSs as a potential candidate for real-time applications.

Preparation of MnS/NiCo2S4 composite nanosheets self-supported electrode and the performance in water-system asymmetric supercapacitors

Abstract In this paper, the MnS@NiCo2S4 composite self-supporting electrode was designed and prepared with a mixture of nickel, cobalt, and manganese sulfide as the research object. The capacitance of the electrode can reach 2, 372.7 F g−1 at the current density of 1 A g−1, and the voltage window can also be widened to 0-0.6 V and maintains a multiplier performance of 62.1% at 10 A g−1. Following 5, 000 cycles of charging and discharging, the electrode exhibits a capacity retention of 78.2% relative to its initial capacity, with the coulombic efficiency consistently hovering around 100%. This performance indicates that the electrode can carry out stable and reversible electrochemical processes. A supercapacitor assembled with 1 M KOH as the electrolyte, activated carbon as the anode, and MnS/NiCo2S4 as the cathode, delivers an energy density of 46.9 W h kg−1. In the life test of the charge and discharge cycle, the discharge capacity after 10, 000 cycles is 89.2% of the initial capacity, indicating that the device has good cycle stability. This study provides an idea for the potential application of metal sulfide-based electrodes with wide potential windows and high electrochemical properties in water asymmetric supercapacitors.

Rational Engineering of Nanostructured NiS/GO/PVA for Efficient Photocatalytic Degradation of Organic Pollutants

A novel nanocomposite film synthesized from an inexpensive and easily accessible polymer such as poly (vinyl alcohol) (PVA), which is coated with nickel sulfide (NiS) and graphene oxide (GO), was obtained from used drinking-water bottles. The produced coated film was examined as a potential photocatalyst film for wastewater treatment promotion in a batch system for the removal of methylene blue (MB) and tetracycline (TC) antibiotics. The experimental results show that the presence of GO significantly increases the photocatalytic efficiency of NiS, and the MB and TC degradation results proved that the incorporation of GO with NiS led to a more than one-and-a-half-fold increase in the removal percentage in comparison with the NiS/PVA-coated film. After 30 min of illumination using GO/NiS/PVA-coated film, the removal efficiency reached 86% for MB and 64% for TC. The photodegradation kinetic rate followed the pseudo-first-order rate. Furthermore, the response surface methodology (RSM) model was utilized to study and optimize several operating parameters. The ideal circumstances to achieve 91% elimination of MB are 12 mg L−1 MB initial concentration, two lamps, and an illumination time of 15 min; however, to achieve 85% TC removal, 11 mg L−1 TC initial concentration, two lamps, and a 45 min illumination time should be used. The fabricated nanocomposite photocatalyst film seems to have promise for use in water purification systems.

Engineered CoS/Ni3S2 Heterointerface Catalysts Grown Directly on Carbon Paper as an Efficient Electrocatalyst for Urea Oxidation

Developing highly efficient and stable electrocatalysts for urea electro-oxidation reactions (UORs) will improve wastewater treatment and energy conversion. A low-cost cobalt sulfide-anchored nickel sulfide electrode (CoS/Ni3S2@CP) was synthesized by electrodeposition in DMSO solutions and found to be highly effective and long-lasting. The morphology and composition of catalyst surfaces were examined using comprehensive physicochemical and electrochemical characterization. Specifically, CoS/Ni3S2@CP electrodes require a potential of 1.52 volts for a 50 mA/cm2 current, confirming CoS in the heterointerface CoS/Ni3S2@CP catalyst. Further, the optimized CoS/Ni3S2@CP catalyst shows a decrease of 100 mV in the onset potential (1.32 VRHE) for UORs compared to bare Ni3S2@CP catalysts (1.42 VRHE), demonstrating much greater performance of UORs. As compared to Ni3S2@CP, CoS/Ni3S2@CP exhibits twofold greater UOR efficiency as a result of a larger electroactive surface area. The results obtained indicate that the synthetic CoS/Ni3S2@CP catalyst may be a favorable electrode material for managing urea-rich wastewater and generating H2.

Nickel sulfide nanoparticles decorated on carbon spheres derived from Verbena officinalis for high-performance asymmetric all-solid-state flexible supercapacitors

The crafting and development of electrode materials possessing extensive energy storage capacities, alongside their adherence to environmental and economic principles, along with their outstanding capacitive behaviors, stand as pivotal elements in propelling the technological progress of supercapacitors. In this study, we utilized discarded Verbena officinalis (VOCs) as a carbon substrate and successfully synthesized porous hollow carbon spheres through an in-situ hydrothermal method, subsequently depositing NiS nanoparticles to form a shell-like structured material. The optimized VOCs/NiS-3 composite material exhibited an exceptional specific capacitance of 202.8 mAh g−1 at a current density of 1.0 A g−1; it maintained 71 % of its capacitance even at a high current density of 10 A g−1 (144.2 mAh g−1). After enduring 10,000 charge-discharge iterations, the preservation of charge storage capacity was 81.7 %, highlighting the material's outstanding performance in terms of rapid charge-discharge rates and enduring stability. Furthermore, within a PVA/KOH gel electrolyte, we fabricated an asymmetric all-solid-state supercapacitor device that delivered an energy density of 32.58 Wh k g−1 at a power density of 800 W k g−1. The device sustained a capacitance loss rate of 9.9 % and a coulombic efficiency of 96.8 % after 5000 cycles. Even after 3000 repeated bending at 120°, the capacitance retention reached 88.3 %, indicating the device's exceptional specific capacitance, flexibility and longevity. This research offers a renewable and waste-resource recycling design strategy for synthesizing outstanding-performance, flexible, all-solid-state supercapacitor electrode materials with NiS deposited on discarded biomass carbon, unveiling considerable potential for enhancing energy storage efficiency.

Minimizing entrainment recovery of ultrafine silicate minerals in pentlandite flotation using carboxymethyl cellulose

The presence of silicate minerals is a common occurrence in various ore types, including nickel sulphide ores. These silicate minerals dilute the grade of flotation concentrates through recovery by entrainment which leads to poor flotation performance and subsequently loss of values. Flotation by entrainment is further enhanced as the particle size of the feed becomes finer. The present work investigates the entrainment characteristics of silicate minerals in the flotation of pentlandite. Within the context of the selective flotation of pentlandite from silicate gangue minerals, the influence of different particle sizes on entrainment flotation was also carried out. PAX was used as a collector for recovering pentlandite, whereas carboxymethyl cellulose (CMC) was employed as a dispersant for the silicate gangue mineral. Microflotation experiment was conducted on a pentlandite-quartz mixture of different particle sizes including − 106 + 75 µm, − 75 + 38 µm, − 38 + 20 µm, and − 20 µm. Electroacoustic zeta potential measurements, Fourier-Transform Infrared (FTIR) Spectroscopy, and Ultraviolet–Visible (UV–Vis) spectroscopy were used to characterise the interaction between pentlandite and quartz and in the presence of PAX and CMC. It was observed during the mixed minerals flotation tests that flotation by entrainment increased with a decrease in feed particle size irrespective of the dosage of CMC. Notwithstanding, the addition of CMC led to notable reduction in entrained silica flotation from 58 % to 38 % in the −20 µm size fraction attributed to improved particle drainage from the froth layer in the presence of CMC. Furthermore, UV–Vis spectroscopy and FTIR results gave further evidence that PAX adsorbed onto pentlandite and quartz minerals surfaces in the presence of CMC, which is consistent with the flotation response observed. Overall, this study confirms entrainment of gangue species is dominant within fine or ultra-fine mineral particles and proposes the use of CMC as a dispersant to limit gangue flotation by entrainment.

Effect of additives on the photocatalytic degradation of malachite green using NiS:Tb3+ nanoparticle and their photoluminescence properties

The contamination of wastewater with synthetic dyes presents a critical challenge, highlighting the need for advanced technologies and approaches to effectively manage, treat, and remediate polluted wastewater and mitigate its adverse environmental and health impacts. This study focuses on the photocatalytic degradation of malachite green dye, a widely used synthetic dye, using nickel sulfide nanoparticles doped with Tb3+ ions. The objective is to explore the potential of this approach in breaking down the dye into harmless components, thereby reducing its toxicological impacts on the environment and human health. The catalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectroscopy (UV). The effects of pH levels and various additives, including transition metals, inorganic oxidants, and inorganic anions, on the degradation process were systematically examined. The results demonstrate a high degradation efficiency of 94 % within 90 min, highlighting the efficacy of the photocatalytic process. Notably, adding transition-metal ions and inorganic oxidants enhanced the degradation rate, whereas inorganic anions had an inhibitory effect. Furthermore, an artificial neural network (ANN) model was developed to predict the degradation rate, demonstrating a strong correlation between experimental data and predicted values. This study provides valuable insights into optimizing photocatalytic degradation processes. It showcases the potential of ANN modelling in predicting the photocatalytic activity of nickel sulfide nanoparticles doped Tb3+ in the presence of various additives.

Electrochemical properties of binder-free micro-blocks/sheets-based cadmium‑nickel-sulfide electrode materials for portable energy storage applications

The major goal of community is to synthesis the novel electrode materials for new energy storage sources to reduce the environmental pollution and to overcome the energy crises in developing countries. Herein, the authors synthesized a binder-free micro-blocks/sheets-based nickel sulfide, cadmium-sulfide‑nickel-sulfide (Ni-S, Cd-S-Ni-S) electrode materials (EMs) on nickel foam by home-made chemical vapor deposition technique. The XRD patterns reveals the development of polycrystalline Ni-S, Cd-S-Ni-S phases. The average crystallite size of Ni-S and Cd-Ni-S EMs are found to be ⁓32 to ⁓45 nm respectively. The microstructure of Ni-S is changed from cluster-of-nanoparticles/micro-blocks to nanosheets when a layer of Cd-S is condensed on Ni-S EMs. The EDX analysis confirms the presence of various wt% of Ni, Cd and S in Ni-S, Cd-S-Ni-S EMs. The molar ratios of Ni and S are found to be 1.46 and 0.46 in the synthesized Ni-S EMs. The molar ratios of Ni, Cd and S are found to be 0.459, 0.439 and 0.702 in the synthesized Cd-S-Ni-S EMs. The maximum values of specific capacitance, energy density and power density of Ni-S and Cd-S-Ni-S EMs are found to be 3305, 4086 F/g at 1 mV/s 25 Wh/kg and 1399 W/kg respectively. The capacitive contribution of Cd-S-Ni-S EMs is higher than Ni-S EMs, however, it is increased with increasing scan rates. The excellent capacity retention (75–92 %), good cyclic stability, impedance analysis show that the synthesized Ni-S, Cd-S-Ni-S EMs are suitable for energy storage devices like supercapacitor and batteries.

Architecture of interconnected cubic NiCo2S4 decorated mesoporous carbon with self-doped nitrogen based-hydrogel for high performance hybrid supercapacitor

Although the transition metal sulfides have shown persuasive proof and stellar traits for energy storage applications, their real applications still possess some obstacles such as prolonged ionic and electronic transport. Hence, NiCo2S4 decorated a pyrolyzed hydrogel (NiCo2S4@PHG) via facile synthesis is considered a promising electrocatalyst for energy storage devices. The prepared electrode materials were characterized utilizing different analysis techniques like XPS, XRD, FT-IR, TGA, SEM, TEM, elemental mapping and EDX that reveal the crucial role of the hydrogel pyrolysis in creating a homogenous nitrogen-doped carbon matrix. The as-fabricated 0.5 NiCo2S4@PHG nanocomposite was electrochemically examined in a sealed workstation cell and showed a clear battery-type supercapacitor behavior attributed to various redox reactions, porosity, and conductivity that was enhanced by self-doped nitrogen. In contrast, composites based on nickel and cobalt sulfides individually with pure hydrogel demonstrated the superiority of binary metal composites. The 0.5 NiCo2S4@PHG electrode exposed a marvelous specific capacity of 317.9 mAh g−1 and capacitance of 2728.5 F g−1 at a current density of 1 A g−1. A hybrid asymmetric supercapacitor was established by 0.5 NiCo2S4@PHG (cathode) and activated carbon (AC, anode), which brought large energy and power densities of 32.8 Wh kg−1 and 750 W kg−1, respectively. The fabricated cell manifests ultra-high retention of 82.6% at a current density of 20 A g−1 after 10,000 cycles. These outstanding accomplishments hold significant potential for practical energy storage and conversion applications.

Oxidation of nickel concentrates in simulated reaction shaft conditions of the flash smelter

The suspension oxidation of nickel sulfide concentrates in flash smelting conditions was studied using a laboratory-scale laminar flow furnace. The effects of temperature (800–1100 °C) and oxygen concentration (40–85 vol%) in the process gas were investigated. The surface morphology and mineralogical compositions of samples were examined using scanning electron microscopy equipped with energy-dispersive X-ray spectrometry. The sulfur removal from concentrates was determined using chemical analysis assuming iron as a non-volatile component. It was found that ignition of the nickel concentrates started at a temperature below 800 °C. The sulfur removal from the sieved concentrates increased with increasing temperature. The oxidation was initiated with preferential oxidation of iron in sulfides forming an iron oxide-rich scale on sulfidic core.

Interface Engineering of Transition Metal-Based Heterostructure Electrocatalysts for Enhanced Hydrogen Evolution Reaction

Electrochemical water splitting to produce clean hydrogen plays a significant role in the development of the hydrogen economy. The rational design of highly efficient and inexpensive electrocatalysts is critical for improving water electrolysis efficiency. Herein, we report the fabrication of heterostructure monometallic, bimetallic, and trimetallic sulfides on Ni foam (NF) as porous self-supported electrodes for hydrogen evolution reaction (HER) via an energy-saving electrodeposition process. Molybdenum-cobalt-nickel sulfide electrode (MoCoNiS@NF) only requires a low overpotential of 114 mV to produce a current density of 10 mA cm-2 for HER, compared with nickel sulfides (NiS@NF, 142 mV) and cobalt-nickel sulfides (CoNiS@NF, 129 mV). The desirable HER performance of MoCoNiS@NF results from the synergistic effect of heterostructure interfaces of multi-metal sulfides, providing high intrinsic catalytic activity and a large amount of catalytic active sites. Electrochemical impedance spectroscopy and Tafel slope analysis proved the fast reaction kinetics of MoCoNiS@NF toward HER. Our present work provides valuable insights into the working mechanisms behind the HER catalytic process and new perspectives for the future design of cost-effective electrocatalysts for HER.

Manufacturing of Fe-Ni Composite Oxide Powder and Leaching Process Optimization Via Nickel Pig Iron(NPI) Raw Materials

The lithium-ion battery industry is experiencing rapid growth in response to the widespread adoption of electric vehicles, leading to a significant increase in demand for high-purity nickel compounds, a critical raw material. As a result, ensuring a smooth supply of nickel resources poses a critical challenge not only for the battery industry but also for enhancing the competitiveness of future clean energy industries. High-purity nickel production is predominantly carried out via the high-pressure acid leach (HPAL) process, which extracts nickel from nickel laterite ores. However, this process involves substantial initial capital investment and consumes significant energy due to high temperatures, high pressure, and strong acids. Additionally, this method is associated with environmental concerns such as water and soil pollution. Furthermore, an alternative approach is proposed, which involves adding sulfur to low-grade nickel pig iron (NPI) to produce the nickel matte, followed by an iron removal process to generate high-purity nickel sulfide. However, this method presents challenges such as waste generation from the iron removal process, high carbon emissions, and the production of large amounts of greenhouse gases. This study explored using anodic oxidation to induce oxidative reactions in NPI to nano-powder. This approach improves nickel recovery efficiency by increasing the surface area compared to the bulk state, allowing leaching at room temperature and atmospheric pressure. As a result, the process becomes simpler, with lower initial capital investment, making it economically viable. Additionally, the process requires less energy consumption, allowing for achieving the breakeven point at an earlier stage. This study compared the characteristics of the nano-powderized NPI under different voltage and current ranges. Furthermore, the nickel leaching efficiency was assessed based on leaching solution conditions.

Analysis of Operational Control Data and Development of a Predictive Model of the Content of the Target Component in Melting Products

The relevance of this research is due to the need to stabilize the composition of the melting products of copper–nickel sulfide raw materials. Statistical methods of analyzing the historical data of the real technological object and the correlation analysis of process parameters are described. Factors that exert the greatest influence on the main output parameter (the fraction of copper in a matte) and ensure the physical–chemical transformations are revealed: total charge rate, overall blast volume, oxygen content in the blast (degree of oxygen enrichment in the blowing), temperature of exhaust gases in the off-gas duct, temperature of feed in the smelting zone, copper content in the matte. An approach to the processing of real-time data for the development of a mathematical model for control of the melting process is proposed. The stages of processing of the real-time information are considered. The adequacy of the models was assessed by the value of the mean absolute error (MAE) between the calculated and experimental values.

Precisely tailoring the d-band center of nickel sulfide for boosting overall water splitting

d‐band center engineering is an effective approach to manipulate the electronic structure of an electrocatalyst for boosting water splitting performance. However, it is still challenging to precisely tailor the electronic structure with an optimized d‐band center for efficient hydrogen and oxygen evolution reactions (HER and OER) on one single catalyst simultaneously. Focusing on nickel sulfide (Ni3S2), herein we applied dual-atom modification to precisely regulate the d‐band center of Ni3S2, which dramatically enhances its bifunctional activity with outstanding HER and OER performance. Specifically, the V and Fe co-modified Ni3S2 achieves ultra-low overpotentials of 68 and 190 mV to output 10 mA cm−2 in 1 M KOH for HER and OER, respectively. Theoretical calculations reveal that the strong electronic interactions between Ni 3d and V 3d/Fe 3d orbitals effectively tailor the d‐band center of Ni3S2, resulting in optimized HER and OER intermediate adsorption, thus boosting the HER and OER simultaneously.

Characteristics and Deep Mineralization Prediction of the Langmuri Copper–Nickel Sulfide Deposit in the Eastern Kunlun Orogenic Belt, China

The discovery of a Cu-Ni sulfide deposit in Langmuri of the Eastern Kunlun Orogenic Belt holds significant geological implications. This study, based on the examination of the metallogenic geological body, metallogenic structure, and metallogenic process characteristics, suggests that the deposit is a magmatic Cu-Ni sulfide deposit formed in the collision of orogenic and post-extension processes of the Late Ordovician. The early mineralization of the deposit was primarily derived from the differentiation of sulfides in the mafic–ultramafic rock (450–439 Ma) of the Late Ordovician, while the late-stage mineralization underwent significant superimposed modification by the magmatic–hydrothermal activity of crustal-contaminated biotite granite (415 Ma). In addition, this article analyzes the measurements of the geochemical studies of sediments, and the magnetic and gravity measurements carried out in the area, focusing on the geochemical and geophysical anomaly characteristics in the study area, and selects favorable exploration areas, which have been confirmed to have multiple mineral bodies. By integrating comprehensive gravity, magnetic, induced polarization, and audio-frequency magnetotelluric profile measurements, this study analyzes delineated mineralized zones and the deep extensions of surface mineral bodies to assess deep mineralization potential and identify deep ore-finding targets. It suggests that diverse and scattered mafic–ultramafic complexes in the Langmuri mining area have a large-scale distribution of ore-bearing rocks in the deep. Through the analysis and inverse of the geophysical data, a deep mineralization predictive model was established in the basic–ultrabasic rock mass. The study presents prospects for the delineation of the deep-seated mineralization in the Langmuri deposit.

Exploring the electrochemical synergy of metal sulfides and metal-organic framework composite as hybrid supercapacitor electrodes

Metal-organic frameworks (MOFs) are promising electrode materials however, they continue to seek improvements in both energy density and electrical conductivity. Within a wide array of available metal nodes and linkers, the task of refining and attaining a profound comprehension of charge storage mechanisms is still to accomplish. Herein nickel sulfide and nickel MOF were synthesized via hydrothermal method, their properties were investigated, and a binary composite was developed due to the high resistance of pristine MOFs. This composite demonstrated exceptional specific capacity of 787.8 C/g at cost of 2.0 A/g. To leverage real-world applications, a supercapattery was fabricated using the NiS/Ni-MOF as the positive electrode material and activated carbon as the negative electrode material. The device possesses maximum specific energy of 64.67 Wh/kg and maximum specific power of 3200 W/kg together with capacity retention of 91 % after 5k charge-discharge cycles. To validate results, semi-empirical approach using Dunn’s model and power law is subjected to investigate the capacitive and diffusive contributions and b-values. This study shows that the binary composites of metallic sulfides with MOFs can possess potentials for their applications in real devices.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) bioanodes in Co-doped modified microbial fuel cell promote sulfamethoxine degradation with high enrichment of electroactive bacteria and extracellular electron transfer

Microbial fuel cell (MFC) is a new renewable energy technology, which has a wide range of applications. In this paper, the refractory organic matter sulfamethoxazole (SMX) was degraded by MFC technology, and the electricity generation performance was analyzed in detail. Since Ni and Fe ions can promote electron transfer, the presence of S ions can enhance the biocompatibility of the material, in this study, nano-ferro nickel sulfide (NiFe2S4) was prepared by hydrothermal method, and co-doped with ferro oxide (Fe3O4) nanoparticles to modify the poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) hydrogel served as the bioanode of MFC. Through high throughput results, we found the enriched electro producing bacteria Desulfuromonas and Fe-S cluster oxidoreductase, proving that bimetallic sulfides have good synergistic effect with metal oxides, which can provide more active sites and accelerate the EET process. The maximum power density obtained as a bioanode in MFC was 3.67 W/m3. During degradation of SMX, the maximum power density was 2.39 W/m3. At the same time, the degradation efficiency of SMX reached 93.78 %, and the chemical oxygen demand (COD) removal rate was 32.52 %. This provides a valuable reference for the degradation of refractory organic compounds such as antibiotic SMX, and also provides multi-dimensional thinking for renewable energy technologies.

Predicting sensitivity to glucose in metal sulfides: A structural and surface characterization study

The increasing prevalence of diabetes is leveraging the development of improved management technologies, including non-enzymatic glucose sensors that offer enhanced stability and longer operation times. However, the lack of reliable methods to predict materials' electrocatalytic activity remains a significant barrier to their advancement. Herein, we obtained transition metal sulfides (CuS, Ag2S, FeS2, and α-NiS) with similar shapes and sizes using wet chemical methods. Detailed structural and surface characterization revealed the presence of metals in mixed oxidation states and the formation of disulfides and polysulfides on the surface of air-exposed materials. The optical measurements supported by theoretical calculations indicated band gaps of 1.74, 0.98, and 1.14 eV in CuS, FeS2, and Ag2S, respectively. Nickel sulfide exhibited an intraband transition at 1.42 eV. The electrocatalytic activity toward glucose was investigated using cyclic voltammetry and chronamperometry. The lowest oxidation potential of 615 mV showed α-NiS, whereas the highest – Ag2S (860 mV). The sensitivity determined in chronoamperometry measurements increased in the order of α-NiS>CuS>Ag2S>FeS2. Furthermore, selectivity studies revealed that FeS2 responded only to strong reductants, while α-NiS to all examined electroactive species. In the last step, a clear relationship was identified between the d-band center position (dbc) in metal sulfides and their electrochemical performance. The dbc relative to the Fermi level is optimal in CuS and NiS (around −2 eV) for forming bonds with glucose and intermediates, while in Ag2S and FeS2, it lays too far or too close for effective electrooxidation.

Calcination process of porous metal–organic frameworks derived from nickel sulfide composites for supercapacitor and computer vision for investigating the porosity-electrochemical correlation

The utilization of metal–organic framework nanostructured electrode materials in supercapacitors and sensor applications is achieved by various chemical methods. In this study, we create NiS and NiS@MOF-BDC by employing nickel precursors and benzene dicarboxylic acid (BDC) as chelating organic linkers through a thermal reduction procedure at a temperature of 400 °C to produce the composite. The composite heterostructure enhanced the conductivity, porous characteristics, and diverse potential morphological qualities. The production of composite electrodes demonstrates a specific capacity of 260F/g (104C/g) when subjected to a current density of 1A/g. Additionally, these electrodes exhibit exceptional cyclic stability, enduring 5000 cycles, when used with a 2 M KOH electrolyte. Moreover, the synthesized composite HR-TEM images were analyzed using computer vision and AI techniques for estimating the porosity and investigating the enhanced electrochemical correlation.

Photo-Excited High-Spin State Ni (III) Species in Mo-Doped Ni3S2 for Efficient Urea Oxidation Reaction.

Designing robust catalystsfor increasing the sluggish kinetics of the urea oxidation reaction (UOR) is challenging. Herein, the regulation of spin states for metal active sites by photoexcitation to facilitate the adsorption of urea and intermediates is demonstrated. Mo-doped nickel sulfide nanoribbon arrays (Mo-Ni3S2@NMF) with excellent light-trapping capacity are successfully prepared. Under AM 1.5G illumination, the activity of the Mo-Ni3S2@NMF exhibits a 50% improvement in the UOR current. Compared with those under dark conditions, Mo-Ni3S2@NMF achieve 10mA cm-2 at 1.315 VRHE for UOR and 1.32 Vcell for urea electrolysis, which are decreases of 15 and 80mV, respectively. The electron spin resonance, in situ Fourier transform infrared spectroscopy analysis and density functional theorycalculations reveal that illumination led to the formation of Ni3+ active sites in a high-spin state, which strengthens the d-p orbital hybridization of Ni-N, hence facilitating the adsorption of urea. C─N cleavage of the *CONN intermediate is further inhibited, which promotes the oxidation of urea molecules via the active N2 pathway, thereby accelerating the UOR rate.