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At present, the rational design and facile synthesis of highly active and low-cost photocatalysts are still facing great challenges. Herein, a series of Zn0.5Cd0.5S/NiS (x mol%) composite photocatalysts have been synthesized via a simple and mild one-pot hydrothermal method. Compared with pure Zn0.5Cd0.5S, the NiS-loaded samples exhibit enhanced photocatalytic hydrogen generation performance, in which the Zn0.5Cd0.5S/NiS-5% sample has the highest H2 production rate of 10 855 ± 461 μmol h−1 g−1 with a quantum yield of 11.82% at 365 nm, which is almost 6.3 times higher than that of pristine Zn0.5Cd0.5S. The high activity of the Zn0.5Cd0.5S/NiS nanosheets may be attributed to their distinct nanostructure, including a short transfer distance of photoinduced charge carriers, a large number of unsaturated surface atoms, and a large surface area. Moreover, the added NiS nanoparticles served as an effective cocatalyst to promote photoinduced electron transfer and enhance the surface kinetics of H2 evolution. Our work provides a simple and effective route for the preparation of sulphur-based photocatalysts, which can significantly improve the efficiency of hydrogen production from water. [ABSTRACT FROM AUTHOR]

We report the synthesis of a new nickel(II) hydroxide complex 2 supported by a rigid, tridentate triazolylidene-carbazolid ligand. The complex can be accessed in high yields following a simple and stepwise extraction protocol using dichloromethane and aqueous ammonium chloride followed by aqeous sodium hydroxide solution. We found that complex 2 is highly basic, undergoing various deprotonation/desilylation reactions with E–H and C–H acidic and silylated compounds. In this context we synthesized a variety of novel, functionalized nickel(II) complexes with trimethylsilylolate (3), trityl sulfide (4), tosyl amide (5), azido (6), pyridine (7), acetylide (8, 9), fluoroarene (10 & 11) and enolate (12) ligands. We furthermore found that 2 reacts with malonic acid dimethyl ester in a knoevennagel-type condensation reaction, giving access to a new enolate ligand in complex 13, consisting of two malonic acid units. Furthermore, complex 2 reacts with acetonitrile to form the cyanido complex 14. The formation of complexes 13 and 14 is particularly interesting, as they underline the potential of complex 2 in both C–C bond formation and cleavage reactions. [ABSTRACT FROM AUTHOR]

The electrochemical nitrate reduction reaction (ENO3RR) is a green ammonia synthesis method under ambient conditions relative to the traditional Haber–Bosch technology, which does not require high-temperature or high-pressure conditions and can convert nitrate pollutants in the environment into value-added NH3, thus achieving a dual purpose. However, more electrocatalysts with a remarkable performance towards high-efficiency ENO3RR need to be developed. In this work, a Cu/NiO-NF composite electrocatalyst with a nanorod structure on nickel foam was successfully fabricated, which contains heterogeneous interfaces between Cu and NiO toward selective electrocatalytic nitrate reduction for ammonia synthesis. The steric nanorod morphology of the catalyst can significantly increase the surface area, expose more active sites, and improve the reaction activity. Moreover, the construction of the composite and the interface effectively boosts the synergistic effect of the active species Cu and NiO, which can regulate the electronic structure of the catalyst, expose more active sites, enhance the conductivity of the material, and accelerate the interfacial electron transfer, thereby further promoting the ENO3RR performance. This Cu/NiO-NF composite exhibits a high NH3 yield of 0.6 mmol h−1 cm−2 and up to 97.81% faradaic efficiency at the optimal applied potential of −1.0 V (vs. RHE) in a concentration of 0.1 M NO3−-containing 0.1 M PBS. Furthermore, it demonstrates excellent electrochemical cycle stability. This work provides insights into the rational design and fabrication of ENO3RR electrocatalysts for potential electrocatalytic applications. [ABSTRACT FROM AUTHOR]

As significant transition metal sulfides, nickel sulfides integrated with carbon were successfully synthesized in the presence of polyethylenimine and glutaraldehyde with a solvothermal route at 180 °C followed by carbonization. Glutaraldehyde prevented complete sulfur loss and allowed the formation of a mixed phase of nickel sulfide. The electrochemical performances of pure NiS2, NiS@C0, NiS2/NiS@C1, and NiS2/NiS@C2 electrodes were tested by a series of measurements. The specific capacitances obtained from GCD analysis were 698, 1160, 1484, and 908 F g−1 at 1 A g−1 for NiS2, NiS@C0, NiS2/NiS@C1, and NiS2/NiS@C2 electrodes, respectively. The results implied that the NiS2/NiS@C1 electrode possessed the highest specific capacitances and this study can be a good reference for the preparation of other hybrid metal sulfides as pseudocapacitive electrode materials. [ABSTRACT FROM AUTHOR]

Hierarchical micro/nanostructures assembled from nanorods and nanosheets have become promising candidates for photocatalysis. In this work, a series of hierarchical Cd-Ni-MOF micro/nanostructures, assembled from nanosheets and nanorods, were fabricated via a two-step solvothermal process involving the partial replacement of Ni2+ with Cd2+ in the Ni-MOF-74 structure. Different morphologies were obtained by considering different volume ratios of DMF and ethanol as the solvent during synthesis. Hierarchical Cd-Ni-MOF-T/CdS/NiS hybrid micro/nanostructures were synthesized by Ni2+ and Cd2+ exchange of Cd-Ni-MOFs with S2−. The as-prepared samples, which were composed of thin nanosheets alone, exhibited the best photocatalytic H2 evolution rate of about 40.08 mmol g−1 h−1. The p–n junction between CdS and NiS was found to be beneficial for the migration of photogenerated electrons from the conduction band (CB) of NiS to the CB of CdS. The heterojunction between CdS and Cd-Ni-MOF-T further promoted the transfer of an electron from the CB of CdS to the CB of Cd-Ni-MOF-T. Thus, this study demonstrated that hierarchical Cd-Ni-MOF-T/CdS/NiS architectures have a large specific surface area, leading to significantly improved photocatalytic activity. [ABSTRACT FROM AUTHOR]

The energy industry is placing more and more emphasis on the need for effective and affordable electrocatalysts for hydrogen evolution reactions (HER). In this work, an iron-doped NiS/Ni(OH)2/CC composite material was synthesized by simple hydrothermal sulfurization processes of bimetallic Prussian blue analogue (PBAs) precursors grown in situ on three-dimensional (3D) Ni(OH)2 nanosheets. The overpotential can be 103 mV to attain current densities of 10 mA cm−2. The excellent catalytic activity of Fe-NiS/Ni(OH)2/CC is because of the unique 3D structure and the uniform doping of iron caused by the in situ growth of PBA, as well as the high conductivity of the self-supported electrode carbon cloth. [ABSTRACT FROM AUTHOR]

Transition metal sulfides have been widely explored as electrode materials for supercapacitors. Unfortunately, the slow redox reaction kinetics and severe volume changes during charge/discharge result in compromised electrochemical performance. In this work, a nickel–cobalt sulfide hollow nanosheet array decorated with cerium oxide nanoparticles (NiCoS/CeO2) has been constructed using a cobalt zeolitic imidazolate framework-L as the template coupled with subsequent solvothermal synthesis. Benefiting from the advantages of the hollow and hierarchical NiCoS nanosheets with a large number of accessible active sites and fast charge transport pathways, as well as CeO2 layers with rich oxygen vacancies and strong interaction between NiCoS and CeO2, NiCoS/CeO2 exhibits a high specific capacity of 1278.1 C g−1 (1 A g−1), which is approximately 1.9 times that of NiCoS. The asymmetric supercapacitor assembled using NiCoS/CeO2 and activated carbon shows an excellent storage capability (34.9 W h kg−1 at 850.0 W kg−1) and an impressive cycle life (91.9% capacitance retention after 10 000 charge and discharge cycles at 10 A g−1). [ABSTRACT FROM AUTHOR]

The lack of electrical conductivity limits the electrochemical kinetic rate of the electrode material, resulting in the inability to reach its theoretical capacity. A facile method is adopted to improve the intrinsic conductivity of binary NiS2/Ni3S4 hybrid nickel sulfide, with the doping of transition metal atoms Co, Mn and Ag. Through the introduction of heteroatoms, the electronic structure of the electrode material is modified and the electrical conductivity is significantly improved, thus enhancing its electrochemical performance. The improvement of conductivity is attributed to the formation of intermediate bands of transition metals and the redistribution of electrons, and the result is demonstrated by experimental and density functional theory (DFT) calculations. As a result, the NiS2/Ni3S4 hybrid nickel sulfide after 0.5% amount of Co-doping reaches the highest specific capacitance of 2874 F g−1 at 1 A g−1, increasing specific capacitance of 653 F g−1 as 29.4% of the specific capacitance of non-doped nickel sulfide. The Co doped nickel sulfide also exhibits remarkable cycling stability compared with non-doped nickel sulfide. The assembled 2% Co-doped nickel sulfide//rGO, 0.5% Mn-doped nickel sulfide//rGO and 0.5% Ag-doped nickel sulfide//rGO asymmetric supercapacitors show a specific energy density of 36.6, 36.1 and 36.0 W h kg−1 at a power density of 800 W kg−1. This study provides a useful insight into the fabrication of high performance pseudocapacitive materials. [ABSTRACT FROM AUTHOR]

The development of high-performance electrode materials and the rational design of asymmetric structures are the two main keys to fabricating micro-supercapacitors (MSCs) with high energy density. Transition metal compounds, especially nickel–cobalt phosphides and hydroxides, are promising electrode materials with excellent pseudo-capacitance. However, they are rarely used in fabricating asymmetric MSCs (AMSCs) due to the limitations of the preparation method. In this work, we constructed hierarchical Ni–Co–P@LDH nanocomposites with outstanding mass specific capacitance (1980 F g−1 at 1 A g−1) via a multi-step electrodeposition method, which is employed with FeOOH to fabricate an interdigital AMSC device (Ni–Co–P@LDHs//PVA–KOH//FeOOH). The as-prepared device exhibits a high working voltage (1.4 V), a large specific capacitance (24.0 mF cm−2 at 0.14 mA cm−2), a high energy density (6.54 μW h cm−2 at a power density of 100 μW cm−2) and good cycling stability (86.5% of capacitance retention after 5000 cycles). This work may provide novel methods for the synthesis of high-performance nickel–cobalt composite materials and their potential applications in interdigital AMSC devices. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs), especially task-specific ILs, are capable of dissolving various solids at moderate temperatures without the need for special reaction vessels. Direct synthesis of binary sulfides of B, Bi, Ge, Mo, Cu, Au, Sn, In, Ti, V, Fe, Co, Ga, Ni, Al, Zn, and Sb in [P66614]Cl was tested at 100 °C, i.e. below the melting point of sulfur. Under these conditions, substantial sulfide formation occurred only for nickel (Ni3S4, Ni3S2, NiS) and copper (Cu2S, CuS). Sb showed no formation of crystalline sulfide, but after addition of EtOH, an orange material precipitated which was identified as amorphous metastibnite. Subsequently, the dissolution of antimony sulfide (Sb2S3), the main source of antimony production, in the phosphonium-based ILs [P66614][OAc] and [P66614]Cl at 100 °C was studied in detail. The dissolution proceeds without H2S evolution, and amorphous Sb2S3 can be precipitated from these solutions. Heating Sb2S3 in the Lewis-acidic IL [BMIm]Cl·4.7AlCl3 led to the crystallization of [Sb13S16Cl2][AlCl4]5, which contains a new quadruple heterocubane cation. [ABSTRACT FROM AUTHOR]

Focusing on the synthesis of nickel-based materials (such as nickel sulfides, nickel hydroxides, and nickel oxides) is an urgent need in the fields of batteries, supercapacitors, and catalysis. However, their controlled synthesis still remains a great challenge because of the inadequate understanding of the control factor of their synthesis. A two-step solvo-/hydrothermal process with halide ion embedding/releasing was proposed to understand the effect of the halide ions on the synthesis and sulfidation of nickel hydroxy-halides. We find that the halide ions determine the formation, growth, and evolution of nickel hydroxy halides and promote them to form unique architectures and morphologies, leading to obvious differences in structural characteristics, including conductivity and electrochemical activity. Because of the presence of halide ions, a series of hybrids with multiple interfaces, which consist of hydroxides and sulfides and have various morphologies, such as flower-like balls, solid balls, porous balls, schistose, and thorny balls, with capacities ranging from 100.7 to 261.2 mA h g−1, can be easily obtained. It is fully demonstrated that the halide anion plays a core role in the synthesis process of nickel-based materials, and this finding will provide more chances for controllably synthesizing high-activity electrode materials. [ABSTRACT FROM AUTHOR]

Transition metal phosphide electrodes, particularly those with unique morphologies and micro-/nanostructures, have demonstrated desirable capabilities for hybrid supercapacitor applications by virtue of their superior electrical conductivity and high electrochemical activity. Here, three-dimensional hierarchical CoFeP@nickel–manganese sulfide nanoarrays were in situ constructed on a flexible carbon cloth via a hydrothermal method, a phosphorization process, followed by an electrodeposition approach. In this smart nanoarchitecture, CoFeP nanorods grown on carbon cloth act as the conductive core for rapid electron transfer, while the nickel–manganese sulfide nanosheets decorated on the surface of CoFeP serve as the shell for efficient ion diffusion, forming a stable core–shell heterostructure with enhanced electrical conductivity. Benefiting from the synergy of the two components and the generation of a heterointerface with a modified electronic structure, The CoFeP@nickel–manganese sulfide electrodes deliver a high capacity of 260.7 mA h g−1 at 1 A g−1, excellent rate capability, and good cycling stability. More importantly, an aqueous hybrid supercapacitor based on CoFeP@nickel–manganese sulfide as a positive electrode and a lotus pollen-derived hierarchical porous carbon as a negative electrode is constructed to display a maximum energy density of 60.1 W h kg−1 at 371.8 W kg−1 and a good cycling stability of 85.7% capacitance retention after 10 000 cycles. [ABSTRACT FROM AUTHOR]

While significant advances have been made in the synthesis of core--/multi-shell materials, the synthetic process usually involves a soft/hard template and complicated procedures. In particular, it is extremely difficult to fabricate single-component core--shell structures for nickel sulfides (NSs) with a controlled phase. In this work, we demonstrate a novel facile method to synthesize a single-component β-NiS ballin-ball microsphere. The ball-in-ball structure is easily obtained by uniquely employing 2-mercaptopropionic acid (2-MPA) as the sulfur source and ethanol as the solvent based on the Ostwald ripening process. In particular, our work demonstrates that the chemical structure of sulfur sources and solvents plays a key role in the formation of the pure β-NiS ball-in-ball structure. When used as an electrode active material, the β-NiS ball-in-ball microspheres exhibit two times stronger specific capacity and three times higher rate performance than NSs produced by a hydrothermal method. The fabricated NS-2//rGO asymmetrical supercapacitor (ASC) displays an energy density of 46.4 W h kg-1 at a power density of 799.0 W kg-1 and good cycling performance. Thus, this study provides a new method for controlling the phase and morphology of NSs. [ABSTRACT FROM AUTHOR]

Rational design of non-noble metal electrocatalysts with high intrinsic activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is extremely impressive for sustainable electrocatalytic water splitting systems. However, it still remains a major challenge to engineer bifunctional performance. Here, we put forward a highly efficient water electrolyzer based on Ni3S2-based materials. The hierarchical structure of Ni3S2 can be well regulated for optimizing the HER catalytic activity. The best c-Ni3S2/NF electrode exhibits a much smaller overpotential of 220 mV to reach the current density of 100 mA cm−2. Upon introducing Fe species onto the Ni3S2/NF electrode by a simple dipping/drying method, the intrinsic OER activity can be extremely improved. As a result, the Fe-c-Ni3S2/NF catalyst showed excellent catalytic activity for the OER, including an overpotential of 193 mV at 10 mA cm−2, high specific current density and excellent stability. Post-characterization studies proved that the remaining S anions have an effective influence on improving the OER intrinsic activity. The assembled water electrolyzer also presented superior performance, such as a very low cell voltage of 1.50 V at 10 mA cm−2 and excellent durability for 120 h in alkaline medium. This strategy provides a promising way to design highly active and low-cost materials for overall water electrolysis. [ABSTRACT FROM AUTHOR]

The integration of metal oxide composite nanostructures has attracted great attention in supercapacitor (SC) applications. Herein, we fabricated a series of metal oxide composite nanostructures, including ZnO nanowires, NiO nanosheets, ZnO/CuO nanowire arrays, ZnO/FeO nanocrystals, ZnO/NiO nanosheets and ZnO/PbO nanotubes, via a simple and cost-effective chemical bath deposition (CBD) method. The electrochemical properties of the produced SCs were examined by performing cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) analysis, and electrochemical impedance spectroscopy (EIS). Of the different metal oxides and metal oxide composites tested, the unique surface morphology of the ZnO/NiO nanosheets most effectively increased the electron transfer rate and electrical conductivity, which resulted in improved energy storage properties. The binder-free ZnO/NiO electrode delivered a high specific capacitance/capacity of 1248 F g−1 (599 mA h g−1) at 8 mA cm−2 and long-term cycling stability over the course of 3000 cycles with a capacity retention of 79%. These results suggested a superiority in performance of the ZnO/NiO nanosheets relative to the nanowires, nanowire arrays, nanocrystals, and nanotubes. Thus, the present work has provided an opportunity to fabricate new metal oxide composite nanostructures with high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

Transition metal sulfides are important candidates of battery-type electrode materials for advanced supercapatteries due to their high electric conductivity and electrochemical activity. The Co9S8@Ni3S2/ZnS composite microplate array was prepared by a metal–organic framework-assisted strategy because the electrochemical properties of composite arrays are governed by the synergistic effects of their diverse structures and compositions. As a battery-type material, the Co9S8@Ni3S2/ZnS electrode expressed an ultrahigh areal specific capacity of 8192 C cm−2 at the current density of 2 mA cm−2, and excellent cycling stability of 79.7% capacitance retention after 4000 cycles. An assembled supercapattery device using the Co9S8@Ni3S2/ZnS microplate array as a positive electrode and active carbon as the negative electrode delivered a high energy density of 0.377 mW h cm−2 at a high power density of 1.517 mW cm−2, and outstanding retention of 95.2% after 5000 cycles. As a result, the obtained Co9S8@Ni3S2/ZnS shows potential for applications in high-performance supercapattery. [ABSTRACT FROM AUTHOR]

This paper proposes a novel μ-hydroxo-bridged dinuclear macrocyclic zinc complex, {[Zn(C10H20N8)]2(OH)}(BF4)3. The structure was determined by X-ray crystallography: Monoclinic, C2/c, a = 25.4632(6), b = 10.9818(3), c = 15.7522(4) Å, Z = 8, R1 = 0.0233, wR2 = 0.0557, based on reflections I > 2σ(I). The complex was successfully reacted with graphene oxide to form a μ-hydroxo-bridged dinuclear macrocyclic Zn complex/reduced graphene oxide composite. To evenly disperse the Zn- and N-rich complex onto the surface of the reduced graphene oxide, and to enhance the electrocatalytic property of the graphene composites, a soluble molecular grafting method was used here. The graphene-based composites were applied as the counter electrodes (CEs) of dye-sensitized solar cells. Current density–voltage measurements revealed that the conversion efficiency of the GO/Zn (1 : 10) sample was 7.78%, which was better than that of Pt CE (7.49%). GO/Zn (1 : 10) CE exhibited the lowest impedance (RCE = 9.90 Ω), which was better than that of Pt CE (RCE = 66.1 Ω), showing that GO/Zn CEs can reduce the impedance at the CE/electrolyte interface. The proposed method is simple, and the composite materials can potentially replace conventional Pt, optimizing efficiency and reducing production cost. [ABSTRACT FROM AUTHOR]

Designing low-cost and high-performance bifunctional electrocatalysts towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is vitally important for water splitting. Herein, we synthesize Co2−xNixO2 (0 < x < 1.0) hexagonal nanosheets with different Co/Ni molar ratios via a facile coprecipitation process followed by calcination under an Ar atmosphere. Changing the Co/Ni molar ratios of the Co2−xNixO2 products is found to have a momentous influence on the microstructures, specific surface areas and electrocatalytic performances. At a Co/Ni molar ratio of 0.6, the Co1.4Ni0.6O2 nanosheet exhibits the largest specific surface area of 60.63 m2 g−1, the best OER with an onset overpotential of 278.5 mV, and HER of 72.8 mV as a bifunctional electrocatalyst. Meanwhile, the minimum Tafel slope is 113.6 mV dec−1 for OER and 77.4 mV dec−1 for HER. The Co1.4Ni0.6O2 nanosheet has excellent OER and HER activity at 0.1 mg cm−2 trace loading. Moreover, we construct an overall water splitting cell using the Co1.4Ni0.6O2 bifunctional electrocatalyst in a two-electrode system to further demonstrate the practical application, which needs a cell voltage of 1.75 V at a current density of 10 mA cm−2 and exhibits great long-term stability. These results provide an efficient strategy for the rational design of Co-based oxides towards bifunctional overall water electrocatalysts. [ABSTRACT FROM AUTHOR]

Trifunctional nickel tin sulfide (NixSn2xS4x) with a thiospinel-like structure composited with multiwalled carbon nanotubes (MWCNTs) (M–NixSn2xS4x) was synthesized by a facile method. The unit cell arrangement of the prepared composite was studied by density functional theory, and the theoretical interpretation satisfactorily inferred the presence of a synergistic effect between the thiospinel and MWCNTs. The high metallic conductivity and superior electrocatalytic activity of the M–NixSn2xS4x composite endow it with diverse applications. The composite shows promise as a counter electrode for dye-sensitized solar cells (efficiency of 4.67% for fluorine-doped indium tin oxide compared to 5.23% for platinum); an efficient catalyst for the hydrogen evolution reaction with good cycling stability and a low overpotential of −41 mV at a cathode current density of 10 mA cm2 and a Tafel slope of 43 mV dec−1 on a graphite sheet electrode; and an impressive capacitance material on a graphite sheet electrode alternative to expensive current collectors such as Ni foam, with a specific capacitance value of 1200 F g−1 at a current density of 1 A g−1 and a long life span of 92.6% that is retained for up to 15 000 cycles. [ABSTRACT FROM AUTHOR]

The encapsulation of small non-noble metal nanoparticles (NPs) within an inorganic layer has received considerable attention owing to their enhanced stability and high catalytic activity. Using a combination of emulsion-free polymerization, inner RF-Ni2+ and outer SiO2 coating, and subsequent carbonization treatment, herein, we have fabricated worm-like structured Ni-based composites in which a high density of nickel NPs are embedded in a carbon layer and also entrapped by SiO2 nanocages. We find that the carbonization temperature plays a vital role in adjusting the size of the Ni NPs. A detailed examination of the encapsulated nickel particles synthesized at 700 °C exhibited the best performance on the catalysis of the reduction of 4-NPs. Moreover, owing to the good alloying ability of the Ni NPs with noble metal NPs, the Ni–Pd alloy NPs are also entrapped in the SiO2 nanocages, which exhibit better performance on the catalysis than the Ni-based composites. The encapsulation of Ni–Pd alloys within SiO2 nanocages also improves stability against agglomeration and metal separation during catalytic operation. [ABSTRACT FROM AUTHOR]

ZnO materials with multidimensional stereoscopic morphologies were synthesized via a one-step solvothermal process with water, ethanol and acetone as solvents. In this work, well-prepared ZnO was used as a Zn source for preparing pristine Li2ZnTi3O8 anode materials for the first time by a facile solid-state method. The resulting Li2ZnTi3O8 electrode material with rice-shaped ZnO as the zinc source (LZTO-E) possessed a smaller particle size and larger specific surface area, which were conducive to increase the electrochemical reaction area. Impressively, the LZTO-E electrode showed an excellent electrochemical performance with large discharge capacity (253.4 mA h g−1 at 100 mA g−1) and good cycling stability (175 mA h g−1, 133.4 mA h g−1, and 115.0 mA h g−1 at 1000 mA g−1, 2000 mA g−1, and 5000 mA g−1 after 500 cycles, respectively). This superior electrochemical performance of the as-synthesized Li2ZnTi3O8 was attributed to the specific microtopography of ZnO. [ABSTRACT FROM AUTHOR]

Heteroatom-doping engineering has been recognized as an effective strategy to improve the activity and stability of electrocatalytic materials. Herein, we fabricated a bimetallic Mo/Mn codoped three-phase nickel sulfide on Ni foam, with Mo/Mn-NixSy/NF successfully synthesized via hydrothermal synthesis and calcination. In order to better explore the codoping effect of Mo/Mn, we also synthesised Ni3S2/NF, NiS@Ni0.96S/NF, Mo-Ni3S2/NF and Mn-NiS@Ni0.96S/NF and their electrocatalytic activities (HER, OER, and overall water splitting) were systematically investigated. As expected, Mo/Mn-NixSy/NF catalysts exhibited excellent catalytic activities and long-term durability. High electrochemical performance of Mo/Mn-NixSy/NF exceeded that of most reported non-precious metal catalysts and also benchmark RuO2, IrO2 and Pt/C. Moreover, in order to better understand the catalytic process, three possible mechanisms were further proposed to rationalize the enhanced electrocatalytic performance. Our work might broaden the avenue to construct efficient non-precious bifunctional catalysts and further develop large-scale electricity-to-hydrogen applications. [ABSTRACT FROM AUTHOR]

Transition metal sulfides with high specific capacity have received increasing research interest in lithium storage. However, the low reversibility of metal sulfides usually leads to the oxidation of Li2S into polysulfides. The dissolution of polysulfides will suppress the regeneration of sulfides due to the loss of Li2S, which usually leads to poor cycling stability of sulfides. Herein, Al2O3 coated Ni3S4 nanoparticles (Ni3S4@Al2O3) have been rationally designed and fabricated via a one-pot hydrothermal process. The regeneration of nickel sulfides, which is the key to cycling stability of sulfides, can be promoted by the localized conversion from metal to metal sulfides because the Al2O3 layer can prevent the diffusion and dissolution of polysulfides. The conversion of Al2O3 to ion-conductive AlF3 can enhance the quick charge transfer process of the lithium ion insertion/extraction reaction. Furthermore, the Al2O3/AlF3 layer can also prevent the growth and aggregation of Ni3S4 nanoparticles to retain the structure of the electrodes during the cycling process. The as-prepared Ni3S4@Al2O3 exhibits a high reversible capacity of 651 mA h g−1 at 500 mA g−1 even after 400 cycles. This method can also be extended to other metal sulfides for improving electrochemical performances. [ABSTRACT FROM AUTHOR]

The article presents abstracts on inorganic chemistry which includes Copper-induced ammonia N-H functionalization, activation of CS2 by a masked terminal nickel sulfide, and Nitrous oxide activation by a cobalt(II) complex for aldehyde oxidation under mild conditions.

Here, we demonstrate a green and environment-friendly pyrolysis route for the synthesis of metal-rich sulphide embedded in an N-doped carbon (NC) framework in the absence of sulphide ions (S2−). The metal–chelate complex (tris(ethylenediamine) metal(ii) sulfate) serves as a new and single source precursor for the synthesis of earth abundant and non-precious hybrid structures such as metal-rich sulphides Co9S8@NC and Ni3S2@NC when MII = Co2+ and Ni2+ and counter sulphate (SO42−) ions are the source of S. Both the hybrids show superior OER activity as compared to commercial RuO2. [ABSTRACT FROM AUTHOR]

NiS2 hollow spheres are successfully prepared by a one-step template free method. Meanwhile, α-NiS hollow spheres can also be synthesized via the calcination of the pre-obtained NiS2 hollow spheres at 400 °C for 1 h in air. The electrochemical performances of the as-prepared NiS2 and α-NiS hollow sphere products are evaluated. When used for supercapacitors, compared with NiS2 hollow spheres, the α-NiS hollow sphere electrode shows a large specific capacitance of 717.3 F g−1 at 0.6 A g−1 and a good cycle life. Furthermore, NiS2 and α-NiS hollow spheres are successfully applied to fabricate non-enzymatic glucose sensors. In particular, the α-NiS hollow spheres exhibit good catalytic activity for the oxidation of glucose, a fast amperometric response time of less than 5 s, and the detection limit is estimated to be 0.08 μM. More importantly, compared with other normally co-existing interfering species, such as ascorbic acid, uric acid and dopamine, the electrode modified with α-NiS hollow spheres shows good selectivity. Moreover, the α-NiS hollow spheres also present good capacity to remove Congo red organic pollutants from wastewater by their surface adsorption ability. [ABSTRACT FROM AUTHOR]

Hierarchical structures of nickel sulfide have been grown by the hydrothermal method. Nickel nitrate hexahydrate and thiourea were used as precursor materials to synthesize nickel sulfide. Ethylenediaminetetraacetic acid was used as a capping agent to achieve monodispersity. The different phases of nickel sulfide and its dependency on the precursor concentration were analyzed by X-ray diffractometry. Transmission electron microscopy analysis was used to confirm the phase changes and morphological behavior of the synthesized material. The morphological evolution of the hierarchical structure formation was studied systematically by scanning electron microscopy. In this study, we explore a novel method to control the synthesis of nickel sulfide hierarchical structures by varying the precursor concentration. The two mixed phases enhanced the catalytic activity in the 4-nitro phenol reduction reaction. [ABSTRACT FROM AUTHOR]

A novel non-enzymatic peroxide sensor has been constructed by using nickel oxide (NiO) thin films as sensing material, which were prepared by a two-step process: (i) electrodeposition of nickel sulfide (NiS) and (ii) thermal air oxidation of as-deposited NiS to NiO. The resultant material is highly porous and comprises interconnected nanofibers. UV-Vis spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) were used for a complete characterization of nanostructured NiO thin films. Cyclic voltammetry study shows that NiO/ITO electrode facilitates the oxidation of hydrogen peroxide and exhibits excellent catalytic activity towards its sensing. The amperometric study of NiO/ITO was carried out to determine the sensitivity, linear range, detection limit of the proposed sensor. The sensor exhibits prominent electrocatalytic activity toward the oxidation of H2O2 with a wide linear range and a low detection limit. The possible use of the synthesized NiO thin films as an effective photocatalyst for the decomposition of phenol is also discussed. [ABSTRACT FROM AUTHOR]