Unveiling the Growth Mechanism of Ordered-Phase within Multimetallic Nanoplates.

Tuning the crystal phase of alloy nanocrystals (NCs) offers an alternative way to improve their electrocatalytic performance, but, how heterometals diffuse and form ordered-phase remains unclear. Herein, for the first time, the mechanism for forming tetrametallic ordered-phase nanoplates (NPLs) is unraveled. The observations reveal that the intermetallic ordered-phase nucleates through crystallinity alteration of the seeds and then propagates by reentrant grooves. Notably, the reentrant grooves act as intermediate NCs for ordered-phase, eventually forming intermetallic PdCuIrCo NPLs. These NPLs substantially outperform for oxygen evolution reaction (221 mV at 10 mA cm-2) and hydrogen evolution reaction (19 mV at 10 mA cm-2) compared to commercial Ir/C and Pd/C catalysts in acidic media. For OER at 1.53 V versus RHE, the PdCuIrCo/C exhibits an enhanced mass activity of 9.8 A mg-1 Pd+Ir (about ten times higher) than Ir/C. For HER at -0. 2 V versus RHE, PdCuIrCo/C shows a remarkable mass activity of 1.06 A mg-1 Pd+Ir, which is three-fold relative to Pd/C. These improvements can be ascribed to the intermetallic ordered-structure with high-valence Ir sites and tensile-strain. This approach enabled the realization of a previously unobserved mechanism for ordered-phase NCs. Therefore, this strategy of making ordered-phase NPLs can be used in diverse heterogeneous catalysis.

Synthesis of Electrical Conductive Metal-Organic Frameworks for Electrochemical Applications.

Electrical conductivity is very important property of nanomaterials for using wide range of applications especially energy applications. Metal-organic frameworks (MOFs) are notorious for their low electrical conductivity and less considered for usage in pristine forms. However, the advantages of high surface area, porosity and confined catalytic active sites motivated researchers to improve the conductivity of MOFs. Therefore, 2D electrical conductive MOFs (ECMOF) have been widely synthesized by developing the effective synthetic strategies. In this article, we have summarized the recent trends in developing the 2D ECMOFs, following the summary of potential applications in the various fields with future perspectives.

Effect of Selective Metallic Defects on Catalytic Performance of Alloy Nanosheets.

Defects in the crystal structure of nanomaterials are important for their diverse applications. As, defects in 2D framework allow surface confinement effects, efficient molecular accessibility, high surface-area to volume-ratio and lead to higher catalytic activity, but it is challenging to expose defects of specific metal on the surface of 2D alloy and find the correlation between defective structure and electrocatalytic properties with atomic precision. Herein, the work paves the way for the controlled synthesis of ultrathin porous Ir-Cu nanosheets (NSs) with selectively iridium (Ir) rich defects to boost their performance for acidic oxygen evolution reaction (OER). X-ray absorption spectroscopy reveals that the oxidized states of Ir in defects of porous NSs significantly impact the electronic structure and decline the energy barrier. As a result, porous Ir-Cu/C NSs deliver improved OER activity with an overpotential of 237 mV for reaching 10 mA cm-2 and exhibit significantly higher mass activity than benchmark Ir/C under acidic conditions. Therefore, the present work highlights the concept of constructing a selective noble metal defect-rich open structure for catalytic applications.

Modulus difference-induced embedding strategy to construct iontronic pressure sensor with high sensitivity and wide linear response range.

Sensitivity and linearity are two crucial indices to assess the sensing capability of pressure sensors; unfortunately, the two mutually exclusive parameters usually result in limited applications. Although a series of microengineering strategies including micropatterned, multilayered, and porous approach have been provided in detail, the conflict between the two parameters still continues. Here, we present an efficient strategy to resolve this contradiction via modulus difference-induced embedding deformation. Both the microscopic observation and finite element simulation results confirm the embedding deformation behavior ascribed to the elastic modulus difference between soft electrode and rigid microstructures. The iontronic pressure sensor with high sensitivity (35 kPa-1) and wide linear response range (0-250 kPa) is further fabricated and demonstrates the potential applications in monitoring of high-fidelity pulse waveforms and human motion. This work provides an alternative strategy to guide targeted design of all-around and comprehensive pressure sensor.

Phenol-Furfural Resin/Graphite/Ag-Based Electrically Conductive Adhesive Composites from Waste Bagasse with Enhanced Thermo-Electric Properties.

This study describes the preparation and evaluation of phenol-furfural resin (PFR) from bagasse and its nanocomposites for electrically conductive adhesive (ECA) application. PFR was prepared with furfural extracted from bagasse using a modified acid digestion method. Three different formulations of PFR nanocomposites with conductive nanoparticles, i.e., PFR-silver, PFR-graphite, and PFR-silver + graphite, were prepared using 20, 40, and 60 w/w% of fillers via the impregnation method. The resultant products were characterized using FT-IR, SEM, EDS, and XRD spectroscopy. Electrical conductivity was measured using a four-probe technique, while band gap was calculated via Tauc plots. The results exhibited a significant rise in electrical conductivity of insulating virgin PFR from 2.6 × 10-4 Scm-1 to 8.2 × 10-1 Scm-1 with a 40 and 20 w/w% blend of Ag and graphite in PFR. This synergism was exhibited because graphite and Ag NPs supply excellent junctions for building networks. Both tend to coalesce due to van der Waals forces and high surface energies. Therefore, conductive pathway numbers can be increased, and the contact area can be effectively enlarged. This ternary composite exhibited the lowest bandgap energy value, i.e., 3.1 eV. Thermogravimetric temperature values T0 and Tdeg were increased up to 120 °C and 484 °C, respectively, showing a significant increase in thermal stability. Therefore, the resultant nanocomposite material has good potential to be employed as an ECA in the electronic industry.

Antifouling and Water Flux Enhancement in Polyethersulfone Ultrafiltration Membranes by Incorporating Water-Soluble Cationic Polymer of Poly [2-(Dimethyl amino) ethyl Methacrylate].

Novel ultrafiltration (UF) polymer membranes were prepared to enhance the antifouling features and filtration performance. Several ultrafiltration polymer membranes were prepared by incorporating different concentrations of water-soluble cationic poly [2-(dimethyl amino) ethyl methacrylate] (PDMAEMA) into a homogenous casting solution of polyethersulfone (PES). After adding PDMAEMA, the effects on morphology, hydrophilicity, thermal stability, mechanical strength, antifouling characteristics, and filtration performance of these altered blended membranes were investigated. It was observed that increasing the quantity of PDMAEMA in PES membranes in turn enhanced surface energy, hydrophilicity, and porosity of the membranes. These new modified PES membranes, after the addition of PDMAEMA, showed better filtration performance by having increased water flux and a higher flux recovery ratio (FRR%) when compared with neat PES membranes. For the PES/PDMAEMA membrane, pure water flux with 3.0 wt.% PDMAEMA and 0.2 MPa pressure was observed as (330.39 L·m-2·h-1), which is much higher than that of the neat PES membrane with the value of (163.158 L·m-2·h-1) under the same conditions. Furthermore, the inclusion of PDMAEMA enhanced the antifouling capabilities of PES membranes. The total fouling ratio (TFR) of the fabricated PES/PDMAEMA membranes with 3.0 wt.% PDMAEMA at 0.2 MPa applied pressure was 36 percent, compared to 64.9 percent for PES membranes.

Probing the behavior and kinetic studies of amphiphilic acrylate copolymers with bovine serum albumin.

This article presents that acrylate copolymers are the potential candidate against the adsorption of bovine serum albumin (BSA). A series of copolymers poly(methyl methacrylate) (pMMA), poly(3-sulfopropyl methacrylate-co-methyl methacrylate) p(SPMA-co-MMA), and poly(dimethylaminoethyl methacrylate-co-methyl methacrylate) p(DMAEMA-co-MMA) were synthesized via free radical polymerization. These amphiphilic copolymers are thermally stable with a glass transition temperature (Tg) 50-120 °C and observed the impact of surface charge on amphiphilic copolymers to control interactions with the bovine serum albumin (BSA). These copolymers pMD1 and pMS1 have surface charges, - 56.6 and - 72.6 mV at pH 7.4 in PBS buffer solution that controls the adsorption capacity of bovine serum albumin (BSA) on polymers surface. Atomic force microscopy (AFM) analysis showed minimum roughness of 0.324 nm and 0.474 nm for pMS1 and pMD1. Kinetic studies for BSA adsorption on these amphiphilic copolymers showed the best fitting of the pseudo-first-order model that showed physisorption and attained at 25 °C and pH 7.4 within 24 h.

TiO2/g-C3N4 Binary Composite as an Efficient Photocatalyst for Biodiesel Production from Jatropha Oil and Dye Degradation.

In the present work, TiO2/g-C3N4 nanocomposites were synthesized by using highly crystalline TiO2 nanorods/rice (NRs) and various percentages of g-C3N4 via a facile, scalable, and inexpensive pyrolysis method. The synthesized nanocomposites were characterized by various techniques, e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N2 adsorption and desorption analysis (BET), Fourier transform infrared spectroscopy (FTIR), UV-vis diffuse reflectance spectroscopy (DRS), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). It was found that biodiesel production by the esterification reaction can be remarkably enhanced by coupling TiO2 with g-C3N4; hereby, it was observed that with increasing percentage of g-C3N4 from 5 to 10 and 15% with respect to TiO2 NRs, the photocatalytic activity rose and the maximum photocatalytic activity with 97% conversion was observed for NC-3, i.e., 15% g-C3N4/TiO2. Moreover, the photoactivity of pristine TiO2 NR aggregates was contrasted with their nanoparticle morphology and was estimated to be slightly better. When applied for photocatalytic Congo red dye degradation, this sample showed a 91% degradation efficiency using only a very small amount of the catalyst. The high catalytic efficiency is attributed to the narrow band gap, exceptionally high surface area, and efficient charge separation properties of the prepared catalysts.

A facile synthesis of CeO2 from the GO@Ce-MOF precursor and its efficient performance in the oxygen evolution reaction.

Electrochemical water splitting has enticed fascinating consideration as a key conduit for the advancement of renewable energy systems. Fabricating adequate electrocatalysts for water splitting is fervently preferred to curtail their overpotentials and hasten practical utilizations. In this work, a series of Ce-MOF, GO@Ce-MOF, calcinated Ce-MOF, and calcinated GO@Ce-MOF were synthesized and used as high-proficient electrocatalysts for the oxygen evolution reaction. The physicochemical characteristics of the prepared samples were measured by diverse analytical techniques including SEM, HRTEM, FTIR, BET, XPS, XRD, and EDX. All materials underwent cyclic voltammetry tests and were evaluated by electrochemical impedance spectroscopy and oxygen evolution reaction. Ce-MOF, GO@Ce-MOF, calcinated Ce-MOF, and calcinated GO@Ce-MOF have remarkable properties such as enhanced specific surface area, improved catalytic performance, and outstanding permanency in the alkaline solution (KOH). These factors upsurge ECSA and intensify the OER performance of the prepared materials. More exposed surface active-sites present in calcinated GO@Ce-MOF could be the logic for superior electrocatalytic activity. Chronoamperometry of the catalyst for 15°h divulges long-term stability of Ce-MOF during OER. Impedance measurements indicate higher conductivity of synthesized catalysts, facilitating the charge transfer reaction during electrochemical water splitting. This study will open up a new itinerary for conspiring highly ordered MOF-based surface active resources for distinct electrochemical energy applications.

A bioresource catalyst system of alginate-starch-activated carbon microsphere templated Cu nanoparticles: Potentials in nitroarenes hydrogenation and dyes discoloration.

The evolution and development of solid-matrix are considered a backbone for supporting and stabilizing of metal nanoparticles (NPs) and are the soul of the catalytic system. In the current study, the alginate-starch microsphere (Alg-St) was cross-linked using CaCl2 as a cross-linker. In addition, the Alg-St microsphere was blended with different percentages of activated carbon (AC). The microspheres adsorbed Cu+2 was reduced to zero-valent copper NPs through NaBH4 and used as a dip-catalyst. The supported Cu NPs cum NaBH4 system was used as dip-catalyst for the hydrogenation of 4-nitrophenol (4NP), 2-nitroanilline (2NA), and degradation of methylene blue (MB) and Congo red (CR) dyes. Among the different kinetics models, the experimental data were well-fitted in the zero-order kinetic model. Moreover pH, and recyclability were studied for 4NP, where the best activity was achieved at pH 7.0 for 4NP. No leaching was observed after 3rd cycle in the catalyst.

Exploring the role of octanol-water partition coefficient and Henry's law constant in predicting the lipid-water partition coefficients of organic chemicals.

Partition coefficients for storage lipid-water (logKlw) and phospholipid-water (logKpw) phases are key parameters to understand the bioaccumulation and toxicity of organic contaminants. However, the published experimental databases of these properties are dwarfs and current estimation approaches are cumbersome. Here, we present partition models that exploit the correlations of logKlw, and of logKpw with the linear combinations of the octanol-water partition coefficient (logKow) and the dimensionless Henry's law constant (air-water partition coefficient, logKaw). The calibrated partition models successfully describe the variations in logKlw data (n = 305, R2 = 0.971, root-mean-square-error (rmse) = 0.375), and in logKpw data (n = 131, R2 = 0.953, rmse = 0.413). With the inputs of logKow and logKaw estimated from the U.S. EPA's EPI Suite, our models of logKlw and logKpw have exhibited rmse = 0.52 with respect to experimental values indicating suitability of these models for inclusion in the EPI Suite. Our models perform similar to or better than the previously reported models such as one parameter partition models, Abraham solvation models, and models based on quantum-chemical calculations. Taken together, our models are robust, easy-to-use, and provide insight into variations of logKlw and logKpw in terms of hydrophobicity and volatility trait of chemicals.

Layer-By-Layer Self-Assembled Dip Coating for Antifouling Functionalized Finishing of Cotton Textile.

The fouling of surfaces such as textiles is a major health challenge, and there is a continuous effort to develop materials and processes to overcome it. In consideration of this, this study regards the development of antifouling functional nanoencapsulated finishing for the cotton textile fabric by employing a layer-by-layer dip coating technique. Antifouling textile finishing was formulated by inducing the nanoencapsulation of the antifouling functional group inside the hydrophobic polymeric shell. Cotton fabric was taken as a substrate to incorporate antibacterial functionality by alternatively fabricating multilayers of antifouling polymeric formulation (APF) and polyelectrolyte solution. The surface morphology of nanoencapsulated finished textile fabric was characterized through scanning electron microscopy to confirm the uniform distribution of nanoparticles on the cotton textile fabric. Optical profilometry and atomic force microscopy studies indicated increased surface roughness in the coated textile substrate as compared to the uncoated textile. The surface thickness of the fabricated textile increased with the number of deposited bilayers on the textile substrate. Surface hydrophobicity increased with number of coating bilayers with θ values of x for single layer, up to y for 20 bilayers. The antibacterial activity of the uncoated and layer-by-layer coated finished textile was also evaluated. It was significant and exhibited a significant zone of inhibition against microbial strains Gram-positive S. aureus and Gram-negative E. coli. The bilayer coating exhibited water repellency, hydrophobicity, and antibacterial activity. Thus, the fabricated textile could be highly useful for many industrial and biomedical applications.

Water Treatment Using High Performance Antifouling Ultrafiltration Polyether Sulfone Membranes Incorporated with Activated Carbon.

Membrane fouling is a continued critical challenge for ultrafiltration membranes performance. In this work, polyether sulfone (PES) ultrafiltration (UF) membranes were fabricated via phase-inversion method by incorporating varying concentrations of APTMS modified activated carbon (mAC). The mAC was thoroughly characterized and the fabricated membranes were studied for their surface morphology, functional groups, contact angle, water retention, swelling (%) porosity, and water flux. The hydrophilicity of mAC membranes also resulted in lower contact angle and higher values of porosity, roughness, water retention as well as water flux. Also, the membranes incorporated with mAC exhibited antibacterial performance against model test strains of gram-negative Ecoil and gram-positive S. aureus. The antifouling studies based on bovine serum albumin protein (BSA) solution filtration showed that mAC membranes have better BSA flux. The higher flux and antifouling characteristics of the mAC membranes were attributed to the electrostatic repulsion of the BSA protein from the unique functional properties of AC and network structure of APTMS. The novel mAC ultrafiltration membranes developed and studied in present work can provide higher flux and less BSA rejection thus can find antifouling applications for the isolation and concentration of proteins and macromolecules.

Unprecedented Dual Role of Polyaniline for Enhanced Pseudocapacitance of Cobalt-Iron Layered Double Hydroxide.

Creating nanosized pores in layered materials can increase the abundant active surface area and boost potential applications of energy storage devices. Herein, a unique synthetic strategy based on polyaniline (PANI) doped 2D cobalt-iron layered double hydroxide (CoFe-LDH/P) nanomaterials are designed, and the formation of pores at low temperature (80 °C) is developed. It is found that the optimized concentration of PANI creates the nanopores on the CoFe-LDH nanosheets among all other polymers. The well-ordered pores of CoFe-LDH/P allow the high accessibility of the redox-active sites and promote effective ion diffusion. The optimized CoFe-LDH/P2 cathode reveals a specific capacitance 1686 (1096 Cg-1 ) and 1200 Fg-1 (720 Cg-1 ) at 1 and 30 Ag-1 respectively, a high rate capability (71.2%), and a long cycle life (98% over 10 000 cycles) for supercapacitor applications. Charge storage analysis suggests that the CoFe-LDH/P2 electrode displays a capacitive-type storage mechanism (69% capacitive at 1 mV s-1 ). Moreover, an asymmetric aqueous supercapacitor (CoFe-LDH/P2//AC) is fabricated, delivering excellent energy density (75.9 Wh kg-1 at 1124 W kg-1 ) with outstanding stability (97.5%) over 10 000 cycles. This work opens a new avenue for designing porous 2D materials at low temperature for aqueous energy storage devices.

Impedance Spectroscopy Analysis of PbSe Nanostructures Deposited by Aerosol Assisted Chemical Vapor Deposition Approach.

This research endeavor aimed to synthesize the lead (II) diphenyldiselenophosphinate complex and its use to obtain lead selenide nanostructured depositions and further the impedance spectroscopic analysis of these obtained PbSe nanostructures, to determine their roles in the electronics industry. The aerosol-assisted chemical vapor deposition technique was used to provide lead selenide deposition by decomposition of the complex at different temperatures using the glass substrates. The obtained films were revealed to be a pure cubic phase PbSe, as confirmed by X-ray diffraction analysis. SEM and TEM micrographs demonstrated three-dimensionally grown interlocked or aggregated nanocubes of the obtained PbSe. Characteristic dielectric measurements and the impedance spectroscopy analysis at room temperature were executed to evaluate PbSe properties over the frequency range of 100 Hz-5 MHz. The dielectric constant and dielectric loss gave similar trends, along with altering frequency, which was well explained by the Koops theory and Maxwell-Wagner theory. The effective short-range translational carrier hopping gave rise to an overdue remarkable increase in ac conductivity (σac) on the frequency increase. Fitting of a complex impedance plot was carried out with an equivalent circuit model (Rg Cg) (Rgb Qgb Cgb), which proved that grains, as well as grain boundaries, are responsible for the relaxation processes. The asymmetric depressed semicircle with the center lower to the impedance real axis provided a clear explanation of non-Debye dielectric behavior.

Ionic liquids as precursors for Fe-N doped carbon nanotube electrocatalysts for the oxygen reduction reaction.

Iron and nitrogen codoped carbons (Fe-N-C) have emerged as promising noble-metal-free catalysts for the oxygen reduction reaction (ORR). However, delicate control over their structure to enhance the catalytic efficiency is still challenging. Herein, we presented the synthesis of novel ionic-liquid (IL) derived nitrogen and iron co-doped carbon nanotube (CNT) based core-sheath nanostructures that can contribute to solving these challenges associated with the ORR. These nanostructures are synthesized by the adsorption of heteroatom containing ILs on the walls of CNTs followed by carbonization. The advantage of using an IL as a nitrogen source is that the obtained catalyst has a high level of N doping and a high surface area. Electrochemical characterization revealed that the N and Fe codoped CNT based core-sheath nanostructures exhibited superior catalytic activities toward the ORR under both alkaline and acidic conditions. Particularly in alkaline solution, the CNT/Fe-N-C catalysts showed better ORR activity compared to the commercial Pt/C catalyst. We suggest that the excellent electrocatalytic performance of CNT/Fe-N-C catalysts is attributed to: (i) the synergistic effect, which provides more catalytic FeNx sites for the ORR, due to the Fe and N co-doping and (ii) the high surface area and excellent electron transfer rate arising from the IL-derived core-sheath structure.

Cefotaxime Loaded Polycaprolactone Based Polymeric Nanoparticles with Antifouling Properties for In-Vitro Drug Release Applications.

The objective of the present study was to achieve the successful encapsulation of a therapeutic agent to achieve antifouling functionality regarding biomedical applications. Considering nanotechnology, drug-loaded polycaprolactone (PCL)-based nanoparticles were prepared using a nano-precipitation technique by optimizing various process parameters. The resultant nano-formulations were investigated for in vitro drug release and antifouling applications. The prepared particles were characterized in terms of surface morphology and surface properties. Optimized blank and drug-loaded nanoparticles had an average size of 200 nm and 216 nm, respectively, with associated charges of -16.8 mV and -11.2 mV. Studies of the in vitro release of drug were carried out, which showed sustained release at two different pH, 5.5 and 7.4 Antifouling activity was observed against two bacterial strains, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The zone of inhibition of the optimized polymeric drug-loaded nanoparticle F-25 against both strains were compared with the pure drug. The gradual pH-responsive release of antibiotics from the biodegradable polymeric nanoparticles could significantly increase the efficiency and pharmacokinetics of the drug as compared to the pure drug. The acquired data significantly noted that the resultant nano-encapsulation of antifouling functionality could be a promising candidate for topical drug delivery systems and skin applications.

Investigation of Hydrothermally Stressed Silicone Rubber/Silica Micro and Nanocomposite for the Coating High Voltage Insulation Applications.

Silicone rubber is a promising insulating material that has been performing well for different insulating and dielectric applications. However, in outdoor applications, environmental stresses cause structural and surface degradations that diminish its insulating properties. This effect of degradation can be reduced with the addition of a suitable filler to the polymer chains. For the investigation of structural changes and hydrophobicity four different systems were fabricated, including neat silicone rubber, a micro composite (with 15% micro-silica filler), and nanocomposites (with 2.5% and 5% nanosilica filler) by subjecting them to various hydrothermal conditions. In general, remarkable results were obtained by the addition of fillers. However, nanocomposites showed the best resistance against the applied stresses. In comparison to neat silicone rubber, the stability of the structure and hydrophobic behavior was better for micro-silica, which was further enhanced in the case of nanocomposites. The inclusion of 5% nanosilica showed the best results before and after applying aging conditions.

Multi-Stressed Nano and Micro-Silica/Silicone Rubber Composites with Improved Dielectric and High-Voltage Insulation Properties.

The scope of silicone rubber (SiR) is confined due to the deprivation of its dielectric propertiesupon exposure to various ambient stresses. The aim of this research is to develop silicone rubber-based composites by employing inorganic oxide fillers for improved dielectric and high voltage insulation properties for widening its scope in the field of electrical appliances. This study reports the preparation of different composites of silicone rubber with varying concentrations of micro and nano-silica fillers. The dielectric propertytrends of these as-prepared neat and impregnated samples were examined via an indigenously developed weathering chamber capable of applying multiple stresses of acid rain, heat, humidity, UVA radiation, and salt fog. Dielectric constant values were measured before and after applying stresses. Upon applying stresses, a periodic decline in dielectric constant was observed. Improved dielectric properties were obtained by adding micro and nano-silica as fillers. A nano silica-incorporated silicone rubber product exhibited good potential for dual applications as dielectric and high voltage insulation.

Impedance Spectroscopic Study of Nickel Sulfide Nanostructures Deposited by Aerosol Assisted Chemical Vapor Deposition Technique.

This research aims to synthesize the Bis(di-isobutyldithiophosphinato) nickel (II) complex [Ni(iBu2PS2)] to be employed as a substrate for the deposition of nickel sulfide nanostructures, and to investigate its dielectric and impedance characteristics for applications in the electronic industry. Various analytical tools including elemental analysis, mass spectrometry, IR, and TGA were also used to further confirm the successful synthesis of the precursor. NiS nanostructures were grown on the glass substrates by employing an aerosol assisted chemical vapor deposition (AACVD) technique via successful decomposition of the synthesized complex under variable temperature conditions. XRD, SEM, TEM, and EDX methods were well applied to examine resultant nanostructures. Dielectric studies of NiS were carried out at room temperature within the 100 Hz to 5 MHz frequency range. Maxwell-Wagner model gave a complete explanation of the variation of dielectric properties along with frequency. The reason behind high dielectric constant values at low frequency was further endorsed by Koops phenomenological model. The efficient translational hopping and futile reorientation vibration caused the overdue exceptional drift of ac conductivity (σac) along with the rise in frequency. Two relaxation processes caused by grains and grain boundaries were identified from the fitting of a complex impedance plot with an equivalent circuit model (Rg Cg) (Rgb Qgb Cgb). Asymmetry and depression in the semicircle having center present lower than the impedance real axis gave solid justification of dielectric behavior that is non-Debye in nature.