Ni Ions Research Articles

Synthesis, structural elucidation, ion flotation and biological evaluation of Ni(II) and Zn(II) Complexes featuring a heterocyclic thiosemicarbazide ligand with their computational studies

Herein, Ni(II) and Zn(II) complexes were synthesized using the heterocyclic thiosemicarbazide ligand (Z)-N-(2-oxoindolin-3-ylidene)nicotinohydrazide (H2L). The structures and geometries of these complexes were identified using elemental analysis, FT-IR, UV-Visible, Mass spectroscopy and thermogravimetric analysis (TGA). These techniques confirmed the composition of the target chelates as [Ni₂(HL)₂Cl₂(H₂O)₄].3H₂O with an octahedral geometry and [Zn(HL)(OAc)(H₂O)] with a tetrahedral geometry. Conductivity measurements indicated the non-ionic nature of the complexes. Moreover, the chelation patterns, structural configurations, and molecular interactions within the complexes were further corroborated through quantum mechanical computations, specifically density functional theory (DFT).An ion flotation method was employed to investigate the removal of nickel and zinc ions from aqueous solutions. This approach involved the formation of a complex between Ni(II) or Zn(II) ions and H₂L, followed by flotation using oleic acid (HOL) as the surfactant. Various parameters, including pH, surfactant and metal ion concentrations, the presence of foreign ions, and temperature, were systematically tested to determine the optimal flotation conditions. Furthermore, the compounds were evaluated for their effects on human carcinoma cells and their antibacterial properties. Additionally, molecular docking studies of the ligand, H₂L and its complexes were performed using the XP Glide module within the Schrödinger suite, targeting HepG2 (PDB ID: 2OH4) and MCF-7 (PDB ID: 3W2S) cell lines.

Synthesis, characterization, and bioactivity of Cu(II), Fe(II), Co(II), Ni(II), and Mn(II) complexes with benzilmonoximethiocarbohydrazide-O-methoxybenzaldehyde: experimental and computational insights.

In this study, a novel ligand, benzilmonoximethiocarbohydrazide-O-methoxybenzaldehyde (HBMToMB), was synthesized and subsequently complexed with Cu(II), Fe(II), Co(II), Ni(II), and Mn(II) ions. The metal complexes were comprehensively characterized using techniques such as NMR, IR, Mass Spectrometry, UV-Vis, elemental analysis (CHNS), and magnetic susceptibility measurements. The complexes exhibited superior antibacterial and antifungal activity compared to the free ligand. In addition, cytotoxicity was evaluated using the brine shrimp lethality bioassay, demonstrating significant activity. Computational studies, including molecular docking, DFT, and ADMET analysis, provided further insights into the compounds' binding affinities and electronic properties. These findings underscore the potential of these metal complexes as promising candidates for therapeutic applications, particularly in antimicrobial and anticancer therapies.

Designing novel Bi-metallic MOFs with optimized Ni and Co ions ratios for enhanced supercapacitor performance

The goal of this work is to assess the novel supercapacitors (Btc-Im-DMF-Nix/Coy) by creating new bimetallic MOFs. The structure of novel bimetallic MOFs is based on the incorporation of varied Ni and Co ions ratios, as well as a large hetero-organic frame containing imidazole (Im), dimethyl formamide (DMF), and benzene tri carboxylic acid (BTC). Furthermore, the effect of the Nix:Coy ratio on the performance of supercapacitors was investigated for Btc-Im-DMF-Ni2/Co1 and Btc-Im-DMF-Ni1/Co2. The new materials were created to compensate for the conventional superapcitors' low energy density. The electrochemical performance of the novel materials is examined by a number of electrochemical studies, including galvanostatic charge/discharge (GSCD), cyclic voltammetry (CV), and surface analysis. The Btc-Im-DMF-Ni1/Co2 has an optimum capacitance of 1640 F g−1 at 1.0 A g−1, in contrast to Btc-Im-DMF-Ni2/Co1, which shows a capacitance of 1234 F g−1 at 1.0 A g−1. After 5000 cycles, Btc-Im-DMF-Ni1/Co2 has a greater cycling stability (91 %) than Btc-Im-DMF-Ni2/Co1 (85.3 %). The Co to Ni ratio of the Btc-Im-DMF-Nix/Coy has a significant impact on the electrochemical activity of the supercapacitor. Within the MOFs network, Co and Ni have shown improved capacity and cycle stability due to their easier electron transport and lower deprotonation energy.

Synthesis, Spectral Characterization, Antimicrobial Activity, DFT Calculations, Molecular Docking and ADME Studies of Novel Schiff Base Co(II), Ni(II), Cu(II) and Zn(II) Complexes Derived from 4-nitro-ortho-phenylenediamine.

A condensation reaction was carried out between 4-nitro-ortho-phenylenediamine and 5-bromosalicyaldehyde to synthesize a novel Schiff base ligand 2,2'-[(1E,1'E)-(4-nitro-1,2-phenylene) bis (azaneylylidene) bis (methaneylylidene)] bis (4-bromophenol) [NB] in the current investigation. This was followed by the synthesis of metallic complexes comprising the Co(II), Ni(II), Cu(II) and Zn(II) transition metal ions. A hexadentate environment encircling metal complexes was corroborated by the results of varied spectroscopic methods that were employed to unravel the structure of the ligand and metal complexes. The Tauc's plot and Urbach energy were utilized for quantifying the optical energy band gap to provide insight into optical characteristics. The Coats-Redfern method of thermal analysis was implemented to do the kinetic and thermodynamic calculations. Furthermore, DFT studies were performed to predict geometrical structures and the stability of the compounds. Thorough investigation to evaluate their biological efficacies, docking studies was executed against COVID-19 main protease (PDB-7VAH), Dengue virus NS2B/NS3 protease (PDB-2FOM) and Mycobacterium Tuberculosis (PDB-5AF3). Apart from this, in silico ADMET studies were also accomplished for elucidation of drug likeness characteristics and the results attained disclose the significant proficiency of synthesized compounds. Besides this, antimicrobial studies were assessed with different microbial strains and result validates cobalt and zinc complexes as most potent against the selected bacterial and fungal strains.

Investigation of ion irradiation effects on mineral analogues of concrete aggregates

Irradiation can cause prominent damage to reactor concrete aggregates leading to amorphization, strength and modulus decrease, radiation induced volume expansion (RIVE) and micro-cracking, which limits their long-term performance. To develop an improved understanding of irradiation effects in concrete, three mineral analogues of concrete aggregates (limestone, marble and quartzite) were irradiated by 5.5 MeV He ions and 13 MeV Ni ions to surface doses of 0.011 displacements per atom (dpa) and 0.23 dpa, respectively, at room temperature. The two different ion species allow irradiation spectrum effects (ionizing and displacive) to be examined. Irradiation induced cracks were observed in He irradiated limestone and marble, and Ni irradiated quartzite. Full amorphization was observed in Ni irradiated quartzite with 14.3 % RIVE, and ∼25 % hardness and modulus decrease, while almost no change was observed in He irradiated quartzite except 4.35 % RIVE, revealing a possible ionization enhanced diffusion effect for high energy light ions. Furthermore, partial amorphization was observed in Ni irradiated marble and limestone matrix with a 12 % hardness decrease in marble while no amorphization was observed for He irradiation with a 20 % hardness increase in limestone matrix. The role of knock-on damage and irradiation spectrum on amorphization, volumetric expansion and mechanical property changes are discussed. Moreover, the onset and critical doses for amorphization and RIVE in quartz are obtained for ion irradiations at room temperature. The dose dependence of RIVE exhibits a delay compared to the amorphization behavior. The superior irradiation resistance of calcite phase compared to quartz phase implies there could be advantages to using calcareous aggregates and lowering the usage of siliceous aggregates for concrete in nuclear power plants for extended operation beyond 60 years. However, other effects such as corrosion, aging and reactions during severe accidents should also be considered, and further investigations are needed.

Preparation and Antifungal Properties of Cyclopropyl Derivatives of 3-Aminoquinazolin-4(3H)-one and Salicylal Schiff Base Nickel(II) Chelate Complex

N-substituted 2-cyclopropyl-3-R-quinazoline-4()-ones [R: NH2 (1), N=CH(2-hydroxyphenyl) (2)] and Ni(II) chelate compound of 2-cyclopropyl-3-[(Z)-(2-hydroxybenzylidene)amino]quinazoline-4(3H)-one (3) were synthesized and their structures and properties were characterized using X-ray diffraction data, computational optimization, 1H and 13C NMR, IR spectroscopy, and diffuse reflectance spectra. Compounds 1 and 2 are monoclinic (space group P21/n). Unit cell parameters (a, b, c) are 9.2529; 4.7246; 22.3460 Å and 10.2811; 4.6959; 30.972 Å for 1 and 2, respectively. Nickel(II) chelate compound crystallizes in an orthorhombic crystal system (space group Pbca). Unit cell parameters (a, b, c) for 3 are 26.5010; 14.8791; 8.904975 Å, respectively. Schiff base 2 in the crystalline state exhibits two rotary isomers in a molar ratio of 1:3, among which only a minor component as a bidentate ligand can form compound 3 with Ni(II) ion. Nickel(II) ion in 3 is coordinated by N donor atoms and deprotonated O atoms of Schiff base ligands to form square-planar chelate node NiN2O2. All synthesized compounds revealed high antifungal activity against bread mold (Mucor mucedo).

Fixed-Bed Columns of Avocado (Persea americana Hass.) Seed and Peel Biomass as a Retainer for Contaminating Metals

This study evaluated the adsorbent capacity of the Ecuadorian avocado (Persea americana Hass.) seed and peel wastes as an alternative method for cadmium (Cd), mercury (Hg), lead (Pb), and nickel (Ni) ion removal from aqueous solutions. The laboratory microscale process was performed using fixed-bed columns containing 1 g of 600 μm particles of biomaterial pretreated with ethanol and ethylene glycol. Subsequently, metal solutions of different concentrations were eluted and measured by flame atomic absorption spectroscopy. Results showed that fixed-bed columns allow efficient adsorption of Pb (2.6 mg/g) with ethanol pretreatment. Lower adsorption capacity was achieved for Cd, Hg, and Ni ions. Favorable adsorption with high retention capacity was found for Pb+2 for the ethanol pretreated bio-adsorbent at higher concentrations (120 mg/L). Lower removal percentages were found for Cd+2, Hg+2, and Ni+2; Ni showed the lowest adsorption capacities and negative RL values, suggesting inefficient adsorbent development. Regeneration of Cd, Hg, and Pb ions from avocado peel and seed showed the highest recovery when 1 mol/L HCl solution was used. Regarding the adsorption isotherms, the Langmuir model was the one that best fit our data, demonstrating that adsorption takes place in a uniform monolayer and that each contaminant ion occupies a single site.

Synthesis, Structural, DFT, In Vitro Biological Exploration, and DNA Interaction of New Ni(II) and Cu(II) Mixed‐Ligand Complexes Featuring 2,2′‐Pyridine‐2,6‐diylbis(1H‐benzimidazole) and 2‐Hydroxy‐naphthaldehyde‐Based Schiff‐Base

ABSTRACTThis research article provides a comprehensive analysis of the preparation, structural characterization, 3D modeling, and biological screening of two novel formulated metal complexes, NiPDBZNPH and CuPDBZNPH. These complexes were obtained by combining 2,2′‐pyridine‐2,6‐diylbis(1H‐benzimidazole) (PDBZ) and 2‐hydroxy‐naphthaldehyde Schiff‐base (NPH) ligands with Ni(II) and Cu(II) ions, resulting in the compounds [Ni (NPH)(PDBZ)(Cl)] and [Cu (NPH)(PDBZ)(Cl)], respectively. Spectroscopic and analytical techniques confirmed that both complexes exhibit octahedral geometry around the central metal ion. Computational studies using density functional theory (DFT) corroborated the molecular structures and investigated the quantum chemical properties of the ligands and complexes. A series of in vitro assays were conducted to assess their anti‐inflammatory, antifungal, antibacterial, and antioxidant properties, revealing enhanced bioactivity compared to the uncoordinated ligands. The potential of NiPDBZNPH and CuPDBZNPH as therapeutic candidates was also explored through interactions with calf thymus DNA (CT‐DNA). Molecular docking simulations targeting specific protein receptors were performed to evaluate binding affinities and ligand–protein interactions, with results highlighting significant interactions within enzyme active sites. These findings emphasize the pivotal role of metal–ligand coordination in enhancing pharmacological properties and contribute valuable insights toward the design of novel therapeutic compounds for use in medicinal chemistry and pharmaceutical research.

Platan seeds-derived PSC/Ni/Co composite with multi-morphologies as tunable microwave absorber

Biomass and its derived carbon materials, due to their glorious application value in the field of microwave absorption, have sparked a new round of research boom. Hereinto, platan seeds-derived carbon-based materials (PSC), offspring from direct carbonization of platan seeds, were ulteriorly processed and subjected to high-temperature carbonization treatment to synthesis PSC/Ni/Co composite with diversified morphology and tunable microwave absorption performance. The effect of nickel and cobalt ion concentrations on the absorption performance of composite materials was investigated in depth. The optimum reflection loss value (RLmin) of PSC/Ni can reach −47.36 dB, while its effective absorption broadband (EAB) is 5.8 GHz, ranging from 12–17.8 GHz, covering almost the whole Ku band. Compared with PSC/Ni composites, PSC/Co fulfils greater advantages in thickness and bandwidth. As for PSC/Ni/Co, the sample exhibits the optimal performance when Ni and Co ions are at equal concentrations, with an RLmin of −48.3 dB and an EAB of 5 GHz (13–18 GHz), which congealed the edges of both. Unequivocally, the morphological polymorphism of carbon-based-derived microwave absorbing materials with platan seeds as the carbon source is crucial to harvset lightweight, efficient and adjustable absorption properties, let alone its relatively simple and feasible preparation method. This may provide a new approach for engineering light-weight, cost effective and eco-friendly absorbing materials.

High-performance overall water electrolysis enabled by a one-step fabricated bifunctional Pt/NiFe LDH catalyst on iron nickel foam

The development of bifunctional electrocatalysts with high efficiency for overall water splitting is still a challenging task. In this work, we introduce a novel one-step synthesis method for Pt/NiFe layered double hydroxide (LDH) on an iron-nickel foam (INF) substrate under mild conditions. This method eliminates the need for additional Ni or Fe ions and facilitates in-situ etching and growth processes under mild conditions, resulting in a higher active surface area, well-dispersed low-loading Pt nanoparticles, and a self-supported electrode without binders. These features collectively enhance electron transfer and catalytic activity for both HER and OER. The Pt/NiFe LDH/INF exhibits remarkable water splitting performance, requiring a cell voltage of only 1.44 V at10 mA cm−2 when used as both anode and cathode. Additionally, it remains stable at 20 mA cm−2 for at least 16 h. The exceptional water splitting activity of Pt/NiFe LDH/INF in alkaline solution can be attributed to the synergistic effects of Pt and NiFe LDH, which improve the hydrogen evolution reaction and oxygen evolution reaction efficiencies. The results provide valuable insights into designing bifunctional electrocatalysts with low Pt loading for optimal water splitting performance at low operating cost.

Mn3O4-MnOOH nanocomposites for the adsorption-based removal of nickel ions from wastewater.

The removal of nickel from wastewater is a significant environmental concern because of its potential hazards to environment. Adsorption is known as an efficient water treatment strategy and there is a growing interest in the development of new adsorbent materials providing rapid adsorption kinetics, cost-effectiveness, and high adsorption capacity. In this study, the feasibility of Mn3O4-MnOOH nanocomposites was evaluated as the adsorbent material for the removal of nickel ions from wastewater. The nanocomposites were prepared using a modified sonochemical method and characterized by XRD analysis and SEM images. Batch adsorption experiments were carried out under different experimental conditions obtained by varying solution pH, adsorbent amount, and contact period. Under the optimum adsorption conditions, the %RE value was recorded around 80% for 10mg/L Ni(II) ions. The adsorption characteristics were investigated with respect to adsorption isotherms and kinetics. Langmuir and Freundlich isotherm models were used to fit the adsorption data and the results indicated that adsorption of nickel ions onto nanocomposite could be complex and obey both monolayer adsorption and heterogeneous surface. Accordingly, maximum adsorption capacity of nanocomposites were calculated as 12.387mg/g. Research works comparing the kinetic models of pseudo-first-order, pseudo-second-order, and Elovich revealed that chemical sorption plays an important role as the rate-limiting step in the adsorption of nickel ions.

On the SRIM prediction of ranges for Ni ions

An experiment to determine the range of Ni ions in matter consisting in the implantation of nickel ions into samples followed by the determination of the depth profile of the implanted ions by nuclear reaction resonance profiling was performed. The experimentally obtained ranges for Ni ions in Fe and Mo were compared with SRIM-2013 (www.srim.org) and TRIM-98 predictions. It was found that the ranges predicted by SRIM-2013 are significantly overestimated whereas the calculation results obtained with TRIM-98 modified to take into account radiation-enhanced diffusion are consistent with the experimental data.

Greatly boosted H2O2 activity in two-electron water oxidation reaction on Zn-based catalysts by doping engineering

Electrocatalytic production of hydrogen peroxide (H2O2) by two electron water oxidation reaction (2e-WOR) is an environmental process with low cost and devoid of H2O2 storage and transportation. ZnO is one of the important promising 2e-WOR catalysts with relatively high activity and selectivity of H2O2. However, the active sites and the effects of oxygen defects of ZnO remain unknown, which hampers the further improvement in H2O2 formation. To explore the active sites and develop Zn-based catalysts with high performance, Ni, Cu and Co ions are chosen to form M0.1Zn0.9O (M = Ni, Cu and Co) catalysts. Combining the experimental results with density functional theory (DFT) calculations, the active site of 2e-WOR on Zn-based catalysts is first discovered to be the 3-coordinated surface Zn without surface oxygen defects since oxygen defects result in a strong interaction of ·OH with catalyst and then impede the 2e-WOR process. Catalysts with high activity and selectivity for 2e-WOR should have small nano-particle sizes without oxygen defects. Co0.1Zn0.9O is obtained with high activity (35.3 mmol min−1·gcat−1) and selectivity (82%) of H2O2 at 3.2 V vs RHE. This work provides valuable perspectives for designing and developing high-performing catalysts in 2e-WOR reaction.

Doping Sulfur in Layered Double Hydroxides with High Hydrophilicity to Accelerate the Charge Transfer and Reduce the Energy Barrier for Efficient Electrocatalytic Splitting Water.

Nowadays, water splitting has been recognized as one of the most attractive ways to produce clean hydrogen energy. Herein, a novel sulfur-doped layered double-hydroxide (namely, S-NiCo-LDH) electrocatalyst with nanocage structure is prepared. After the etching treatment with Ni ions, the spatial structure of the catalysts is opened, and the hydrophilicity is improved, which will enhance the adsorption capacity for H2O to provide convenience for hydrogen evolution reaction (HER). Interestingly, the S doping can boost the capture capability toward OH- to create conditions for the occurrence of oxygen evolution reaction (OER). More importantly, the introduction of S element can improve the density of states located near the Fermi level of NiCo-LDH, thereby accelerating the electron transfer and increase the carrier density. Meanwhile, the existence of S element can remarkably reduce the energy barriers of *O and *H formation, boosting HER and OER in an alkaline solution. As a result, the S-NiCo-LDH electrocatalyst shows excellent performance in overall water splitting, affording low overpotentials of 168 and 235 mV at 10 mA/cm2 for HER and OER, respectively. Furthermore, the S-NiCo-LDH electrocatalyst exhibits good long-term stability in both HER and the OER. In short, the current work can give a meaningful reference for future research.

Efficient Removal of Cu(II) and Ni(II) Ions from Aqueous Solutions Using Reduced Graphene Oxide/Bentonite Clay/ZnO Nanocomposites: Kinetics, Mechanisms, and Adsorption Performance

<p style="text-align:justify;text-indent:36.0pt;"><span style="font-family:"Arial","sans-serif";font-size:11pt;line-height:150%;">To assess the efficacy of removing heavy metals such as Cu (II) and Ni (II) ions from aqueous solution, the adsorption behaviour of a nanocomposite powder comprising of reduced Graphene Oxide (rGO), bentonite clay, and ZnO was investigated. Various analytical techniques including Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, Energy-Dispersive X-ray spectroscopy, X-Ray diffraction analysis, and N<sub>2</sub> adsorption/desorption analysis were utilized to analyse the synthesized composites. Through the batch equilibrium approach, parameters influencing adsorption behaviours, including initial metal ion concentration, pH, adsorbent dosage, and contact time, were comprehensively examined. Adsorption data were shown to have good fit to the Langmuir isotherm model and pseudo-first-order model, with high R<sup>2</sup>, low root mean square error (RMSE), low chi square (Χ<sup>2</sup>), and low standard deviation (SD) values when using the linear regression approach. For the raw sample (rGO/ bentonite clay) containing copper and nickel, equilibrium was achieved in 80 minutes, while for samples with 1% (rGO/ bentonite clay/1% ZnO), 3% (rGO/ bentonite clay/3% ZnO), and 5% (rGO/ bentonite clay/5% ZnO), equilibrium was attained within 70 minutes. </span><span style="background-color:white;font-family:"Arial","sans-serif";font-size:11pt;line-height:150%;">Within the pH range of 2 to 12, the adsorption kinetics of copper and nickel exhibited a notable pH-dependent relationship, highlighting the pronounced influence of pH conditions on the adsorption process</span><span style="background-color:white;color:#374151;font-family:"Segoe UI","sans-serif";font-size:11pt;line-height:150%;">. </span><span style="background-color:white;font-family:"Arial","sans-serif";font-size:11pt;line-height:150%;">Copper consistently demonstrated superior removal efficiency compared to nickel in all conducted adsorption tests, attributed to its heightened propensity for bond formation with adsorbent surfaces.</span><span style="font-family:"Arial","sans-serif";font-size:11pt;line-height:150%;"> The primary pathways for copper and nickel adsorption on the composites involved intermolecular interactions, cation exchange, physisorption and electrostatic interactions. The Langmuir model revealed maximum Cu (II) adsorption capacities of 312.5 mg/g, 217.39 mg/g, 161.95 mg/g, and 101.96 mg/g for raw sample, 1%, 3%, and 5% samples, respectively. Nickel (II) adsorption capacity were measured at 252.41 mg/g, 185 mg/g, 125.03 mg/g, and 96.60 mg/g for the raw sample, 1%, 3%, and 5% samples, respectively.</span></p>

Oxyanions Enhancing Crystallinity of Reconstructed Phase for Oxygen Evolution Reaction.

The catalysts were always undergoing continuous amorphization and dissolution of active structure in operating condition, hindering the compatibility between stability and activity for oxygen evolution reaction (OER). Herein, we propose the selective adsorption of leached NO3 - to strengthen the crystallinity and activity of surface reconstructed layer with amorphous and crystalline (a-c) heterojunction. Taking a-c Ni doped Fe2O(OH)3NO3 ⋅ H2O (Ni-FeNH) as a model precatalyst, we uncover that the leached NO3 - are readily adsorbs on the crystalline phase in the formed a-c Fe(Ni)OOH (Thank you for your reminding. In our paper, Fe(Ni)OOH was used to refer to a hetero-phase consisting of NiOOH and FeOOH) during OER, lowering the disorder degree and further activating Ni and Fe ion of the crystalline Fe(Ni)OOH on a-c heterojunctions. Accordingly, Ni-FeNH deliver a low overpotential of 303 mV and high durability of 500 hours at 500 mA cm-2 for OER. Particularly, constructing industrial water electrolysis equipment exhibits high stability of 100 hours under a high operating current of 8000 mA.

Oxyanions Enhancing Crystallinity of Reconstructed Phase for Oxygen Evolution Reaction

AbstractThe catalysts were always undergoing continuous amorphization and dissolution of active structure in operating condition, hindering the compatibility between stability and activity for oxygen evolution reaction (OER). Herein, we propose the selective adsorption of leached NO3− to strengthen the crystallinity and activity of surface reconstructed layer with amorphous and crystalline (a‐c) heterojunction. Taking a‐c Ni doped Fe2O(OH)3NO3 ⋅ H2O (Ni−FeNH) as a model precatalyst, we uncover that the leached NO3− are readily adsorbs on the crystalline phase in the formed a‐c Fe(Ni)OOH (Thank you for your reminding. In our paper, Fe(Ni)OOH was used to refer to a hetero‐phase consisting of NiOOH and FeOOH) during OER, lowering the disorder degree and further activating Ni and Fe ion of the crystalline Fe(Ni)OOH on a‐c heterojunctions. Accordingly, Ni−FeNH deliver a low overpotential of 303 mV and high durability of 500 hours at 500 mA cm−2 for OER. Particularly, constructing industrial water electrolysis equipment exhibits high stability of 100 hours under a high operating current of 8000 mA.

Design of high-performance binary carbonate/hydroxide Ni-based supercapacitors for photo-storage systems

Silicon solar cells were used to convert solar energy into electrical energy, and a supercapacitor was designed to store this energy. To maximize the surface area of the electrodes, a three-dimensional Ni foam substrate was employed, onto which Ni-based compounds were deposited to enhance the electrochemical performance of the electrodes. Specifically, to address the conductivity reduction problem that arises when using only Ni ions, we introduced transition metal ions such as Mn, Co, Cu, Fe, and Zn to create binary compounds as electrode material. These binary metal compounds provided high electronic conductivity, structural stability, and reversible capacity, thereby optimizing the performance of the supercapacitor. As a result, the optimized NiCo(CO3)(OH)2 electrode demonstrated high capacity and excellent cycle stability, exhibiting an energy density of 35.5 Wh kg−1 and a power density of 2555.6 W kg−1 as an asymmetric supercapacitor device. Furthermore, when this device was combined directly with silicon solar cells, it achieved a storage efficiency of 63 % and an overall efficiency of 5.17 % under an illumination intensity of 10 mW cm−2. These findings suggest the potential for commercializing high-performance self-charging energy storage devices and contribute significantly to the advancement of energy storage technology.

Facile Synthesis of Polypyrrole-Decorated RGO-CuS Nanocomposite for Efficient Nickel Removal from Wastewater.

Efficient wastewater treatment, particularly the removal of heavy metal ions, remains a challenging priority in environmental remediation. This study introduces a novel sandwich-structured nanocomposite, RGO-CuS-PPy, composed of reduced graphene oxide (RGO), copper sulfide (CuS), and polypyrrole (PPy), synthesized via a straightforward hydrothermal method. The unique combination of RGO, CuS, and PPy offers enhanced adsorption capacity for Ni(II) ions due to RGO's high surface area and CuS's active binding sites, supported by PPy's structural stability contributions. This study is among the first to explore this specific nanocomposite architecture for Ni(II) removal, achieving an adsorption capacity of 166.67 mg/g and a high removal efficiency of 94.9% within 210 min for 55 mg/L of Ni(II) concentration at pH 6 and adsorbent dose of 3 mg/15 mL. The kinetic analysis shows the best fitted time-dependent experimental data with the pseudo-second-order model, indicating chemisorption. Isotherm studies confirmed the Langmuir model as the best fit, yielding a high monolayer adsorption capacity of 166.67 mg/g. Thermodynamic analysis shows the adsorption process was endothermic (ΔH° = 80.23 kJ/mol) and spontaneous (ΔG° ranging from -6.985 to -14.399 kJ/mol). Additionally, reusability tests using 0.1 M HCl for desorption demonstrated good reusability, emphasizing the RGO-CuS-PPy nanocomposite's potential as a sustainable adsorbent for Ni(II) removal in wastewater treatment applications.

Conformational Changes and Coordination Stability of Flexible Tripeptides During Ni(II)-mediated Self-assembly.

The rational design of artificial supramolecular structures with specific properties and functions hinges the comprehensive understanding of the coordination and noncovalent interactions driving self-assembly. Herein, the self-assembly of supramolecular systems through octahedral coordination between Ni(II) ions and a flexible tripeptide was theoretically investigated using quantum chemical calculations. These calculations utilized the B3LYP functional with the polarizable continuum model. Our results indicate that tridentate sites have a greater propensity for coordination, and that the presence of chloride anions and conformational shifts enhance bidentate and monodentate coordination. Insights into the effect of counter anions on the stability of octahedral coordination and the prerequisites for self-assembly were gained by determining the stable conformation and potential reaction pathways of the tripeptide before and after adding chloride anions through an efficient automated conformational search. The formation of intramolecular hydrogen bonding interactions during the conformational changes was also studied using model calculations. Possible processes for initial self-assembly of tripeptide were proposed. This study enhances the fundamental understanding of the conformational behavior of building blocks during supramolecular formation and advance the potential for constructing future bioinspired complexes.