Zn掺杂Co9S8纳米材料的制备及其在超级电容器和电催化析氢中的应用

采用原位溶剂热生长法设计合成了锌掺杂Co₉S₈纳米颗粒。各种表征技术和性能测试结果表明：锌掺杂Co₉S₈纳米颗粒的孔尺寸为18 nm,比表面积为23 m²·g^-1;同时微量的锌掺杂显著增强了Co₉S₈的电催化析氢（HER）活性及电容器性能。在HER性能测试中,当电流密度为10 mA·cm^-2时电位为-361 mV,电流密度最高可达38.26 mA·cm^-2,且具有优异的循环稳定性。同时在电容器性能测试中具有较高的比电容,当电流密度为1 A·g^-1时,质量比电容和面积比电容分别为235.48 F·g^-1和812.4 mF·cm^-2。     

General Formation of MxCo3−xS4 (M=Ni,Mn, Zn) Hollow Tubular Structures for Hybrid Supercapacitors

A simple and versatile method for general synthesis of uniform one‐dimensional (1D) M_xCo_3−xS₄ (M=Ni, Mn, Zn) hollow tubular structures (HTSs), using soft polymeric nanofibers as a template, is described. Fibrous core–shell polymer@M‐Co acetate hydroxide precursors with a controllable molar ratio of M/Co are first prepared, followed by a sulfidation process to obtain core–shell polymer@M_xCo_3−xS₄ composite nanofibers. The as‐made M_xCo_3−xS₄ HTSs have a high surface area and exhibit exceptional electrochemical performance as electrode materials for hybrid supercapacitors. For example, the MnCo₂S₄ HTS electrode can deliver specific capacitance of 1094 F g⁻¹ at 10 A g⁻¹, and the cycling stability is remarkable, with only about 6 % loss over 20 000 cycles.     

Preparation of Yolk‐Shell and Filled Co9S8 Microspheres and Comparison of their Electrochemical Properties

In this study, we report the first preparation of phase‐pure Co₉S₈ yolk–shell microspheres in a facile two‐step process and their improved electrochemical properties. Yolk–shell Co₃O₄ precursor microspheres are initially obtained by spray pyrolysis and are subsequently transformed into Co₉S₈ yolk–shell microspheres by simple sulfidation in the presence of thiourea as a sulfur source at 350 °C under a reducing atmosphere. For comparison, filled Co₉S₈ microspheres were also prepared using the same procedure but in the absence of sucrose during the spray pyrolysis. The prepared yolk–shell Co₉S₈ microspheres exhibited a Brunauer–Emmett–Teller (BET) specific surface area of 18 m² g^?1 with a mean pore size of 16 nm. The yolk–shell Co₉S₈ microspheres have initial discharge and charge capacities of 1008 and 767 mA h g^?1 at a current density of 1000 mA g^?1, respectively, while the filled Co₉S₈ microspheres have initial discharge and charge capacities of 838 and 638 mA h g^?1, respectively. After 100 cycles, the discharge capacities of the yolk–shell and filled microspheres are 634 and 434 mA h g^?1, respectively, and the corresponding capacity retentions after the first cycle are 82 % and 66 %.     

Multi-stage Ordered Mesoporous Carbon-graphene Aerogel-Ni3S2/Co4S3 for Supercapacitor Electrode

Transition metal sulfides have emerged as promising materials in supercapacitor. In this work, we firstly developed an interface-induced superassembly approach to fabricate NiS_x and CoS_x nanoparticles, which based on ordered mesoporous carbon-graphene aerogel composites for supercapacitor electrodes. The obtained multi-component superassembled nanoparticles-carbon matrix composites have controllable 3D porous structure of multi-stage composite. The two-dimensional graphene interlaced to form a 3D framework with large sponge-like pores, and then the graphene surface was loaded with mesoporous carbon with mesoporous pore size and vertical orientation. The composites display high specific capacitance of 958.1 F g⁻¹ at 0.1 A g⁻¹. The capacitance retains about 97.3 % after 3000 charging-discharging cycles at 2 A g⁻¹. These results indicate that the obtained OMC−GA−Ni₃S₂/Co₄S₃ is a promising material for electrochemical capacitors, which providing new technical methods and ideas for the research of new energy and analytical sensor materials in the fields of energy storage, photocatalysis, point-of-care testing devices and other fields.     

Enhanced Supercapacitor Performance Using a Co3O4@Co3S4 Nanocomposite on Reduced Graphene Oxide/Ni Foam Electrodes

To avoid an enormous energy crisis in the not-too-distant future, it be emergent to establish high-performance energy storage devices such as supercapacitors. For this purpose, a three-dimensional (3D) heterostructure of Co₃O₄ and Co₃S₄ on nickel foam (NF) that is covered by reduced graphene oxide (rGO) has been prepared by following a facile multistep method. At first, rGO nanosheets are deposited on NF under mild hydrothermal conditions to increase the surface area. Subsequently, nanowalls of cobalt oxide are electro-deposited on rGO/Ni foam by applying cyclic-voltammetry (CV) under optimized conditions. Finally, for the synthesis of Co₃O₄@Co₃S₄ nanocomposite, the nanostructure of Co₃S₄ was fabricated from Co₃O₄ nanowalls on rGO/NF by following an ordinary hydrothermal process through the sulfurization for the electrochemical application. The samples are characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The obtained sample delivers a high capacitance of 13.34 F cm⁻² (5651.24 F g⁻¹) at a current density of 6 mA cm⁻² compared to the Co₃O₄/rGO/NF electrode with a capacitance of 3.06 F cm⁻² (1230.77 F g⁻¹) at the same current density. The proposed electrode illustrates the superior electrochemical performance such as excellent specific energy density of 85.68 W h Kg⁻¹, specific power density of 6048.03 W kg⁻¹ and a superior cycling performance (86% after 1000 charge/discharge cycles at a scan rate of 5 mV s⁻¹). Finally, by using Co₃O₄ @Co₃S₄/rGO/NF and the activated carbon-based electrode as positive and negative electrodes, respectively, an asymmetric supercapacitor (ASC) device was assembled. The fabricated ASC provides an appropriate specific capacitance of 79.15 mF cm⁻² at the applied current density of 1 mA cm⁻², and delivered an energy density of 0.143 Wh kg⁻¹ at the power density of 5.42 W kg⁻¹.     

Sulfur‐Rich Phosphorus Sulfide Molecules for Use in Rechargeable Lithium Batteries

A new family of sulfur‐rich phosphorus sulfide molecules (P₄S_10+n ) and their electrochemical reaction mechanism with metallic Li has been explored. These P₄S_10+n molecules are synthesized by the reaction between P₄S₁₀ and S. For Li batteries, the P₄S₄₀ molecule in the series of P₄S_10+n molecules provides the highest capacity, which has a first discharge capacity of 1223 mAh g⁻¹ at 100 mA g⁻¹ and stabilizes at approximately 720 mAh g⁻¹ at 500 mA g⁻¹ after 100 cycles. This new class of sulfur‐rich P₄S_10+n molecules and its electrochemical behavior for room‐temperature Li⁺ storage could provide novel insights for phosphorus sulfide molecules and high‐energy batteries.     

Hierarchical FeCo2S4@FeNi2S4 Core/Shell Nanostructures on Ni Foam for High-Performance Supercapacitors

The design of electrode materials with rational core/shell structures is promising for improving the electrochemical properties of supercapacitors. Hence, hierarchical FeCo₂S₄@FeNi₂S₄ core/shell nanostructures on Ni foam were fabricated by a simple hydrothermal method. Owing to their structure and synergistic effect, they deliver an excellent specific capacitance of 2393 F g⁻¹ at 1 A g⁻¹ and long cycle lifespan as positive electrode materials. An asymmetric supercapacitor device with FeCo₂S₄@FeNi₂S₄ as positive electrode and graphene as negative electrode exhibited a specific capacitance of 133.2 F g⁻¹ at 1 A g⁻¹ and a high energy density of 47.37 W h kg⁻¹ at a power density of 800 W kg⁻¹. Moreover, the device showed remarkable cycling stability with 87.0 % specific-capacitance retention after 5000 cycles at 2 A g⁻¹. These results demonstrate that the hierarchical FeCo₂S₄@FeNi₂S₄ core/shell structures have great potential in the field of electrochemical energy storage.     

Rational Design and Synthesis of Hybrid Porous Polymers Derived from Polyhedral Oligomeric Silsesquioxanes via Heck Coupling Reactions

Heck coupling reactions are introduced as an efficient method to prepare porous polymers. Novel inorganic‐organic hybrid porous polymers (HPPs) were constructed via Heck coupling reactions from cubic functional polyhedral oligomeric silsesquioxanes (POSS), iodinated octaphenylsilsesquioxanes (OPS) and octavinylsilsesquioxanes (OVS) using Pd(OAc)₂/PPh₃ as the catalyst. Here, two iodinated OPS were used, IOPS and p‐I₈OPS. IOPS was a mixture with 90% octasubstituted OPS (I₈) and some nonasubstituted OPS (I₉), while p‐I₈OPS was a nearly pure compound with ≥99% I₈ and ≥93% para‐substitution. IOPS and p‐I₈OPS reacted with OVS to produce the porous materials HPP‐1 and HPP‐2, which exhibited comparable specific surface areas with S_BET of 418 ± 20 m² g⁻¹ and 382 ± 20 m² g⁻¹, respectively, with total pore volumes of 0.28 ± 0.01 cm³ g⁻¹ and 0.23 ± 0.01 cm³ g⁻¹, respectively. HPP‐1 showed a broader pore size distribution and possessed a more significant contribution from the mesopores, when compared with HPP‐2, thereby indicating that IOPS may induce more disorder because of the geometrical asymmetry. HPP‐1 and HPP‐2 possessed moderate carbon dioxide uptakes of 134 and 124 cm³ g⁻¹ at 1 bar at 195 K, making them promising candidates for CO₂ capture and storage. The synthesized porous polymers may be easily post‐functionalized using the retained ethenylene groups.

     

Zeolitic Imidazolate Frameworks Derived Co9S8/Nitrogen-Doped Hollow Porous Carbon Spheres as Efficient Bifunctional Electrocatalysts for Rechargeable Zinc–Air Batteries

The development of nonprecious metal-based electrocatalysts with remarkable catalytic activity and long-cycling lifespan toward oxygen reduction reaction (ORR) and evolution reaction (OER) is especially important for rechargeable zinc–air batteries (ZABs). Herein, monodispersed Co₉S₈ nanoparticles embedded in nitrogen-doped hierarchically porous hollow carbon spheres (Co₉S₈ NPs/NHCS) are synthesized through a template-assisted strategy followed by a co-assembly, thermal annealing, and sulfurization process. Benefiting from larger specific surface area, hierarchically porous hollow structure, and carbon nanotubes self-growth, the obtained Co₉S₈ NPs/NHCS-0.5 electrocatalyst exhibits decent performance for ORR (E_1/2=0.85 V) and OER (E₁₀=1.55 V). A rechargeable ZAB assembled using the Co₉S₈ NPs/NHCS-0.5 as air cathode delivers a maximum power density of 116 mW cm⁻², high open circuit voltage of 1.47 V, and good durability (no obvious voltage decay after 1200 cycles (200 hours)). Such a hierarchically porous hollow structure of Co₉S₈ NPs/NHCS-0.5 provides a confined space shell and an interconnected hollow core to achieve outstanding bifunctional catalytic activity and cycling stability, which surpass the benchmark Pt/C-RuO₂.     

负载硫化钴纳米颗粒的N、S共掺杂石墨烯氧还原电催化剂的制备及性能

采用D-氨基葡萄糖作为Co分散剂和碳源,硫脲作为氮源和硫源,以NaCl为模板制备负载硫化钴纳米颗粒的N、S共掺杂三维石墨烯氧还原电催化剂(CoS/N/S/rGO)。CoS/N/S/rGO具有良好的氧还原反应(ORR)活性,起始电位和半波电位分别为960和815 mV,性能与商业Pt/C相当。此外,CoS/N/S/rGO表现出明显的4电子转移特性和超低的过氧化氢产率。与基于Pt/C的锌-空气电池相比,基于CoS/N/S/rGO的锌-空气电池在6 mol·L~(-1) KOH和0.2 mol~(-1) Zn(CH_3COO)_2碱性电解质中显示出更高的恒电流放电性能以及更好的稳定性。     

Sensitive Voltammetric Determination of Methyl Parathion Using a Carbon Paste Electrode Modified with Mesoporous Zirconia

A mesoporous zirconia modified carbon paste electrode was developed for electrochemical investigations of methyl parathion (MP, Phen‐NO₂). The significant increase of the peak currents and the improvement of the redox peak potential indicate that mesoporous zirconia facilitates the electronic transfer of MP. The oxidation peak current was proportional to the MP concentration in the range from 1.0×10⁻⁸ to 1.0×10⁻⁵ mol L⁻¹ with a detection limit of 4.6×10⁻⁹ mol L⁻¹ (S/N=3) after accumulation under open‐circuit for 210 s. The proposed method was successfully applied to the determination of MP in apple samples.     

General Synthesis of Sulfonate-Based Metal–Organic Framework Derived Composite of MxSy@N/S-Doped Carbon for High-Performance Lithium/Sodium Ion Batteries

A general and simple strategy is realized for the first time for the preparation of metal sulfide (M_xS_y) nanoparticles immobilized into N/S co-doped carbon (NSC) through a one-step pyrolysis method. The organic ligand 1,5-naphthalenedisulfonic acid in the metal–organic framework (MOF) precursor is used as a sulfur source, and metal ions are sulfurized in situ to form M_xS_y nanoparticles, resulting in the formation of M_xS_y/NSC (M=Fe, Co, Cu, Ni, Mn, Zn) composites. Benefiting from the M_xS_y nanoparticles and conductive carbon, a synergistic effect of the composite is achieved. For instance, the composite of Fe₇S₈/NSC as an anode displays excellent long-term cycling stability in lithium/sodium ion batteries. At 5 A g⁻¹, large capacities of 645 mA h g⁻¹ and 426.6 mA h g⁻¹ can be retained after 1500 cycles for the lithium-ion battery and after 1000 cycles for the sodium-ion battery, respectively.     

Enhanced Electrocatalytic Water Oxidation by Interfacial Phase Transition and Photothermal Effect in Multiply Heterostructured Co9S8/Co3S4/Cu2S Nanohybrids

The rational design of advanced nanohybrids (NHs) with optimized interface electronic environment and rapid reaction kinetics is pivotal to electrocatalytic schedule. Herein, we developed a multiple heterogeneous Co₉S₈/Co₃S₄/Cu₂S nanoparticle in which Co₃S₄ germinates between Co₉S₈ and Cu₂S. Using high-angle annular-dark-field imaging and theoretical calculation, it was found that the integration of Co₉S₈ and Cu₂S tends to trigger the interface phase transition of Co₉S₈, leading to Co₃S₄ interlayer due to the low formation energy of Co₃S₄/Cu₂S (−7.61 eV) than Co₉S₈/Cu₂S (−5.86 eV). Such phase transition not only lowers the energy barrier of oxygen evolution reaction (OER, from 0.335 eV to 0.297 eV), but also increases charge carrier density (from 7.76×10¹⁴ to 2.09×10¹⁵ cm⁻³), and creates more active sites. Compared to Co₉S₈ and Cu₂S, the Co₉S₈/Co₃S₄/Cu₂S NHs also demonstrate notable photothermal effect that can heat the catalyst locally, offset the endothermic enthalpy change of OER, and promote carrier migrate, reaction intermediates adsorption/deprotonation to improve reaction kinetics. Profiting from these favorable factors, the Co₉S₈/Co₃S₄/Cu₂S catalyst only requires an OER overpotential of 181 mV and overall water splitting cell voltage of 1.43 V to driven 10 mA cm⁻² under the irradiation of near-infrared light, outperforming those without light irradiation and many reported Co-based catalysts.     

Molecular Expansion for Constructing Porous Organic Polymers with High Surface Areas and Well-Defined Nanopores

Construction of porous organic polymers (POPs) with high surface areas, well-defined nanopores, and excellent stability remains extremely challenging because of the unmanageable reaction process. Until now, only a few reported POPs have Brunauer-Emmett-Teller (BET) surface areas (S_BET) exceeding 3000 m² g⁻¹. Herein, we demonstrate a molecular expansion strategy to integrate high surface areas, large nanopore sizes, and outstanding stability into POPs. A series of hyper-crosslinked conjugated polymers ( HCCPs ) with exceptional porosity are synthesized through this strategy. Specially, HCCP-6 and HCCP-11 exhibit the highest surface areas (S_BET >3000 m² g⁻¹) and excellent total pore volumes (up to 3.98 cm³ g⁻¹) among these HCCPs . They present decent total CH₄ storage capacities of 491 and 421 mg g⁻¹ at 80 bar and 298 K, respectively. Meanwhile, they are highly stable in harsh environments. The facile and general molecular expansion strategy would lead to improved synthetic routes of POPs for desired functions.     

General Formation of MxCo3−xS4 (M=Ni,Mn, Zn) Hollow Tubular Structures for Hybrid Supercapacitors

A simple and versatile method for general synthesis of uniform one‐dimensional (1D) M_xCo_3?xS₄ (M=Ni, Mn, Zn) hollow tubular structures (HTSs), using soft polymeric nanofibers as a template, is described. Fibrous core–shell polymer@M‐Co acetate hydroxide precursors with a controllable molar ratio of M/Co are first prepared, followed by a sulfidation process to obtain core–shell polymer@M_xCo_3?xS₄ composite nanofibers. The as‐made M_xCo_3?xS₄ HTSs have a high surface area and exhibit exceptional electrochemical performance as electrode materials for hybrid supercapacitors. For example, the MnCo₂S₄ HTS electrode can deliver specific capacitance of 1094 F g^?1 at 10 A g^?1, and the cycling stability is remarkable, with only about 6 % loss over 20 000 cycles.     

Facile synthesis of cobalt oxide/reduced graphene oxide composites for electrochemical capacitor and sensor applications

Reduced graphene oxide sheets decorated with cobalt oxide nanoparticles (Co₃O₄/rGO) were produced using a hydrothermal method without surfactants. Both the reduction of GO and the formation of Co₃O₄ nanoparticles occurred simultaneously under this condition. At the same current density of 0.5 A g⁻¹, the Co₃O₄/rGO nanocomposites exhibited much a higher specific capacitance (545 F g⁻¹) than that of bare Co₃O₄ (100 F g⁻¹). On the other hand, for the detection of H₂O₂, the peak current of Co₃O₄/rGO was 4 times higher than that of Co₃O₄. Moreover, the resulting composite displayed a low detection limit of 0.62 μM and a high sensitivity of 28,500 μA mM⁻¹cm⁻² for the H₂O₂ sensor. These results suggest that the Co₃O₄/rGO nanocomposite is a promising material for both supercapacitor and non-enzymatic H₂O₂ sensor applications.     

Co3O4纳米片的制备及其电化学电容性能

以配位超分子化合物为前驱物,通过液相氧化分解得到了六方形CoOOH纳米片,进而在空气中热处理制得了Co₃O₄纳米片。利用XRD、TEM、FESEM对CoOOH和Co₃O₄纳米片的结构和形貌进行了表征。电化学测试表明,Co₃O₄纳米片电极在6 mol·L^-1 KOH溶液中表现出良好的电化学电容特性,在电流密度为1 A·g^-1其单电极比容量可达到227 F·g^-1。     

Hierarchical Nanoboxes Composed of Co9S8−MoS2 Nanosheets as Efficient Electrocatalysts for the Hydrogen Evolution Reaction

The development of hydrogen evolution catalysts based on nonprecious metals is essential for the practical application of water‐splitting devices. Herein, the synthesis of Co₉S₈?MoS₂ hierarchical nanoboxes (HNBs) as efficient catalysts for the hydrogen evolution reaction (HER) is reported. The surface of the hollow cubic structure was organized by CoMoS₄ nanosheets formed through the reaction of MoS₄^2? and Co²⁺ released from the cobalt zeolite imidazole framework (ZIF‐67) templates under reflux in a mixture of water/ethanol. The formation process for the CoMoS₄ HNB structures was characterized by TEM images recorded at various reaction temperatures. The amorphous CoMoS₄ HNBs were converted through sequential heat treatments into CoS_x?MoS₂ and Co₉S₈?MoS₂ HNBs. Owing to their unique chemical compositions and structural features, Co₉S₈?MoS₂ HNBs have a high specific surface area (124.6 m² g^?1) and superior electrocatalytic performances for the HER. The Co₉S₈?MoS₂ HNBs exhibit a low overpotential (η₁₀) of 106 mV, a low Tafel slope of 51.8 mV dec^?1, and long‐term stability in an acidic medium. The electrocatalytic activity of Co₉S₈?MoS₂ HNBs is superior to that of recently reported values, and these HNBs prove to be promising candidates for the HER.     

Fabrication of Cobaltosic Oxide Nanoparticle-Doped 3 D MXene/Graphene Hybrid Porous Aerogels for All-Solid-State Supercapacitors

MXenes are a new family of 2 D transition metal carbides and nitrides, which have attracted enormous attention in electrochemical energy storage, sensing technology, and catalysis owing to their good conductivity, high specific surface area, and excellent electrochemical properties. In this work, a series of Co₃O₄-doped 3 D MXene/RGO hybrid porous aerogels is designed and prepared through a facile in situ reduction and thermal annealing process, in which the reduced graphene oxide (RGO) conductive network can electrically link the separated Co₃O₄-MXene composite nanosheets, leading to enhanced electronic conductivity. It is found that upon using the Co₃O₄-MXene/RGO hybrid porous aerogel prepared with a mass ratio of Co₃O₄-MXene/RGO of 3:1 (CMR31) as an electrode for a supercapacitor, a superior specific capacitance of 345 F g⁻¹ at the current density of 1 A g⁻¹ is achieved, which is significantly higher than those of Ti₃C₂T_x MXene, RGO, and MXene/RGO electrodes. In addition, a high capacitance retention (85 % of the initial capacitance after 10 000 cycles at a high current density of 3 A g⁻¹) and a low internal resistance R_s (0.44 Ω) can be achieved. An all-solid-state asymmetric supercapacitor (ASC) device is assembled using CMR31, and it has the ability to light up a blue LED indicator for 5 min if four ASCs are connected in series. Therefore, these novel Co₃O₄-MXene/RGO hybrid porous aerogels have potential practical applications in high-energy storage devices.     

Facile Preparation of CuCo2S4/Cu7.2S4 Nanocomposites as High-Performance Cathode Materials for Rechargeable Magnesium Batteries**

Rechargeable magnesium batteries (RMBs) have been considered a promising energy-storage device due to their high energy density and high safety, but they still suffer from a lack of high-rate performance and cycle performance of the cathode. Nanosized CuCo₂S₄/Cu_7.2S₄ composites have been synthesized for the first time by a facile solvothermal method. Herein, the magnesium ion storage behavior when applied in the cathode for RMBs is discussed. Electrochemical results demonstrated that the CuCo₂S₄/Cu_7.2S₄ composites exhibit a high initial discharge capacity of 256 mAh g⁻¹ at 10 mA g⁻¹ and 123 mAh g⁻¹ at 300 mA g⁻¹ at room temperature and an outstanding long-term cyclic stability over 300 cycles at 300 mA g⁻¹. Furthermore, the electrochemical storage mechanism demonstrated that the storage process of magnesium ion in the CuCo₂S₄/Cu_7.2S₄ cathode is mainly driven by strong pseudocapacitive effects.