查找使用阿拉丁产品的科研文献

Co(OH)2-NiCo2O4 hybrid nanosheets coupled with N-doping reduced graphene oxide as efficient electrocatalysts for Zn-air batteries

Xiaomin Peng,Jinming Zhang,Tianlun Cen,Zhifeng Ye,Yiyi Liu,Dingsheng Yuan

2-dimensional Co(OH) 2 -NiCo 2 O 4 hybrid nanosheets coupled with N-doping reduced graphene oxide (N-RGO) have been prepared by a facile two-step hydrothermal method for exploring the cost-effective and durable bifunctional oxygen electrocatalysts of Zn-air batteries. Co(OH) 2 -NiCo 2 O 4 /N-RGO exhibits the excellent catalytic activity for ORR with a positive half-wave potential of 0.80 V vs. RHE in 0.1 M KOH. And the assembled rechargeable Zn-air battery achieves a high open-circuit voltage of 1.485 V, a large peak power density of 99 mW cm −2 , and a remarkable cycle life of over 180 h. This work offers an inspiration to obtain efficient electrocatalysts for sustainable energy devices.

In-situ generated NiCo2O4/CoP polyhedron with rich oxygen vacancies interpenetrating by P-doped carbon nanotubes for high performance supercapacitors

Yu Liu,Zhenlin Ma,Xiumei Chen,Yulong Ying,Weidong Shi

Supercapacitor with high storage capacity and small volumes are the development trends of miniaturization and portable energy storage systems. Herein, we design a novel self-supporting P-doped carbon nanotube (P-CNT) intercalating NiCo 2 O 4 /CoP core–shell polyhedron film. P-CNT is an ideal substrate with high electrical conductivity and interconnected porous architecture, which can enable the electrons transport to an external circuit from the electroactive component. NiCo 2 O 4 /CoP core–shell fluffy polyhedrons are derived from metal-organic frameworks with rich oxygen vacancies and abundant characteristics of pseudocapacitance, as well as better wettability. The self-supporting composite film readily achieves an ultra-high gravimetric and volumetric capacitance of 1918.4 F g −1 and 1074.3 F cm −3 at 1 A g −1 . Accordingly, as-assembled hybrid supercapacitors using two binder-free electrodes, i.e., a self-supporting composite film as the positive electrode and P-doped CNT integrating graphene film as the negative electrode, harvest a remarkable gravimetric/volumetric energy density of 68.6 W h kg −1 (41.8 W h L −1 ) at 800 W kg −1 (488 W L −1 ). Our work suggests that the rational-designed NiCo 2 O 4 /CoP@P-CNTs electrode is a competitive candidate for designing next-generation supercapacitors with high volumetric energy density.

Macro-/meso-porous NiCo2O4 synthesized by template-free solution combustion to enhance the performance of a nonenzymatic amperometric glucose sensor

Xiao Xuechun,Zhang Xuanming,Zhang Zhanyu,You Junda,Liu Sirui,Wang Yude

A sensitive nonenzymatic amperometric glucose sensor is described that relies on a glassy carbon electrode modified with a macro-/meso-porous NiCo 2 O 4 . NiCo 2 O 4 with spinel structure has been prepared via a one-step solution combustion method. The material was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen absorption/desorption. An electrode was coated with the porous material and then displayed excellent electrocatalytic activity towards the direct oxidation of glucose in 0.15 M NaOH solution by cyclic voltammetry. Amperometric I-t curve demonstrated a sensitivity of 2100 μA·mM −1 ·cm −2 at an applied potential of 0.45 V (vs Hg/HgCl). The sensor has a linear response in the 0.001 to 1.0 mΜ glucose concentration range, a fast response time (3.9 s) and a low detection limit (0.38 μΜ). Graphical abstract

Architecting an indirect Z-scheme NiCo2O4@CdS–Ag photocatalytic system with enhanced charge transfer for high-efficiency degradation of emerging pollutants

Yanqing Cong,Jiaxin Yi,Shengna Liang,Feng Zhang,Yi Zhang,Shi-Wen Lv

Bimetallic oxides with spinel structure show great prospects in the photocatalysis owing to many active sites. Herein, a novel 500NiCo 2 O 4 @CdS–5%Ag composite was fabricated via a feasible strategy. Interestingly, the combination with NiCo 2 O 4 could significantly enhance the absorption ability of CdS for visible light. Benefiting from the formation of heterojunction structure between NiCo 2 O 4 and CdS, the recombination of photogenerated electrons and holes was remarkably restrained. As an effective mediator, deposition of Ag could further promote the transfer of photogenerated charge carriers, thereby accelerating the reaction rate. Meanwhile, light absorption capacity of composite was also improved, owing to the surface plasmon resonance effect of metallic Ag. More importantly, 500NiCo 2 O 4 @CdS–5%Ag composite with great stability displayed an excellent performance in the photocatalytic degradation of OFX, and its highest removal efficiency was as high as 99.14%. Possible degradation pathways of OFX were given, and most of OFX could be degraded into CO 2 , H 2 O and other by-products with no toxicity. Significantly, the separation and transfer of photogenerated charge carriers followed indirect Z-scheme heterojunction mechanism. The O 2 − , OH and 1 O 2 were main active species in photocatalytic reaction system. All in all, current work inspired some new ideas for designing novel photocatalytic system in wastewater treatment .

Carbon Cloth Loaded NiCo2O4 Nano-Arrays to Construct Co-MOF@GO Nanocubes: A High-Performance Electrochemical Sensor for Non-Enzymatic Glucose

Bairui Tao,Jiao Li,Fengjuan Miao,Yu Zang

Hierarchically porous graphene/wood-derived carbon activated using ZnCl2 and decorated with in situ grown NiCo2O4 for high–performance asymmetric supercapacitors

Mei-Jiao Zeng,Xiaofeng Li,Shu-Meng Hao,Jin Qu,Wei Li,Jing Wu,Tianyu Zhao,Zhong-Zhen Yu

Although wood-derived carbon (WC) and its derivatives are promising electrodes for supercapacitors because of their hierarchically porous architecture, superior mechanical flexibility, and environmental friendliness, pure WC electrodes usually exhibit poor wettability, inferior areal capacitance, and unsatisfactory electrical conductivity. Herein, hierarchically porous graphene/wood-derived carbon (GWC) aerogels are fabricated for high-performance supercapacitor electrodes by chemical reduction of graphene oxide/wood hydrogels, followed by directional-freezing, freeze-drying, and carbonization at 1000 °C. An activated GWC (AGWC) anode is prepared by activating GWC using ZnCl2 to create more mass transport paths and increase wettability, while the cathode is synthesized by in situ growth of NiCo2O4 (NCO) in the channels of GWC to bring about pseudocapacitance and increase energy storage sites. The resultant NCO@GWC cathode and AGWC anode exhibit superior capacitances of 8540 and 10 965 mF cm−2 (854 and 183 F g−1) at 1 mA cm−2, respectively. The assembled NCO@GWC//AGWC asymmetric supercapacitor exhibits a superior areal capacitance of 7116 mF cm−2 at 1 mA cm−2, a high energy density of 2.2 mW h cm−2 (5.6 mW h cm−3), a power density of 45.1 mW cm−2 (112.8 mW cm−3), and an excellent cycling stability of 100% capacitance retention over 1000 cycles at 10 mA cm−2.

Solution-phase vertical growth of aligned NiCo2O4 nanosheet arrays on Au nanosheets with weakened oxygen–hydrogen bonds for photocatalytic oxygen evolution

Suisui He,Jian Chai,Siyu Lu,Xijiao Mu,Ruitong Liu,Qiang Wang,Fengjuan Chen,Yuee Li,Jingang Wang,Baodui Wang

Vertical heterojunctions of two-dimensional (2D) semiconducting materials have attracted more and more research interest recently due to their unique optical, electrical, and catalytic properties and potential applications. Although great progress has been made, vertical integration of the layered materials formed by 2D semiconductor nanosheets and 2D plasmatic metal nanosheets remains a huge challenge. Here, we demonstrate for the first time a solution-phase growth of vertical plasmatic metal–semiconductor heterostructures in which aligned NiCo2O4 nanosheet arrays vertically grow on a single Au nanosheet, forming vertically aligned NiCo2O4–Au–NiCo2O4 sandwich-type heterojunctions with hierarchical open channels. Such vertical NiCo2O4–Au–NiCo2O4 heterojunctions can effectively promote the separation and transfer of a photoinduced charge. Density functional theory (DFT) studies and time-resolved transient absorption spectroscopy show that electrons transfer from NiCo2O4 to Au, and the formation of the heterojunction weakens the H–O bond of H2O. Due to the unique structure and superiority of the component, the vertical NiCo2O4–Au–NiCo2O4 heterojunctions exhibit significant activity with an O2 production rate of up to 33 μmol h−1 and long-term stability for photocatalytic water oxidation. We calculated the apparent quantum efficiency (AQE) to be 21.9% for NiCo2O4–Au–NiCo2O4 heterojunctions at the wavelength λ = 450 ± 10 nm, which is higher than that of NiCo2O4 nanosheets (10.9%), Au nanosheets (0.96%) and other photocatalysts. The present study paves the way for the controlled synthesis of novel vertical heterojunctions based on 2D semiconductor nanosheets and 2D metal nanosheets for efficient photocatalysis.

Molten salt-templated synthesis of ternary NiS–NiCo2O4@C composites as high performance catalysts for 4-nitro phenol reduction and supercapacitor

Shakiaz Ahmad,Chao Yang,Wenyu Xie,Zhibo Deng,Heng Zhang,Yunlong Zhao,Xintai Su

The integration of two transition metals with carbon materials provides a great potential to boost the catalytic and electrochemical properties of supercapacitor . However, a scalable fabrication of such composite materials remains a challenge. Here, ternary composites of NiS–NiCo 2 O 4 @C nanosheets were derived from nickel and cobalt oleate using Na 2 SO 4 as both hard template and sulfur source. The NiS–NiCo 2 O 4 @C composites were then tested as catalysts toward rapid reduction of 4-nitrophenol (4-NP) and as electrode materials for supercapacitors. It was found that the catalytic and electrochemical properties of the composites were tuned by adjusting the ratios of Co to Ni and annealing temperature. The optimized composite showed the highest reduction rate constant for 4-NP reduction (1.78 min −1 ). In addition, this composite has also shown high specific capacitance of 1411 F g −1 at 1 A g −1 and 99.5% capacity retention after 2000 continuous charge-discharge cycles at a current density of 3 A g −1 , which is much higher than their respective monometallic Co and Ni composites. Furthermore, the ASC device (CN14//AC) achieved a high energy density of 37.2 W h kg −1 at a power density of 799.9 W kg −1 , and a good cycling performance of retention(89%) after 5000 cycles.

Hierarchical sheet-like W-doped NiCo2O4 spinel synthesized by high-valence oxyanion exchange strategy for highly efficient electrocatalytic oxygen evolution reaction

Jiabing Luo,Xingzhao Wang,Yufeng Gu,Shutao Wang,Yanpeng Li,Tingyong Wang,Yang Liu,Yan Zhou,Jun Zhang

Limited specific surface area, active site amount, and intrinsic conductivity inhibit spinels' electrocatalytic oxygen evolution reaction (OER) activity. Herein, we proposed a high-valence oxyanion exchange strategy for preparing hierarchical sheet-like W-NiCo 2 O 4 -2 spinel OER electrocatalyst, which exhibits favorable activity (306 mV overpotential@10 mA cm −2 ) and durability in 1.0 M KOH solution, and shows an application prospect in a home-made anion exchange membrane (AEM) electrolyzer. BET results showed that the hierarchical structure increased specific surface area and corresponding edge active sites amount, accelerated mass transport and charge transfer. XPS, ex-situ Raman spectroscopy, and HRTEM characterizations dispicted that W 6+ doping optimizes e g orbital electron filling and promotes M−OOH (M = Co, W) active species generation. DFT calculations reveal that W 6+ doping modulates the adsorption of oxygen intermediates, improving the reaction kinetics, and increasing the density of electronic states nearby the Fermi level, thus enhancing conductivity. This work provides a universal pathway for modulating spinel-based OER electrocatalysts.

Catalytic performance and mechanism of PTFE modified NiCo2O4 in high-salt organic wastewater treatment during wet air oxidation at ambient pressure

Liangjie Wang,Chunxiang Geng,Dawei Yu,Daoqing Liu,Hao Sun,Ke Xiao,Huazhang Zhao

High temperatures and high pressures restrict the application of catalytic wet air oxidation (CWAO). Thus, realizing the high performance of CWAO under ambient pressure (AP-CWAO) is attractive. In this study, hydrophobic modification by polytetrafluoroethylene (PTFE) was adopted to enhance the O 2 transfer and salts resistibility of hollow microspheres NiCo 2 O 4 (HM-NiCo 2 O 4 ), for harvesting an efficient catalyst of AP-CWAO to treat high-salt wastewater. Under ambient pressure in 10 g/L NaCl solution, PTFE modified HM-NiCo 2 O 4 (PHM-NiCo 2 O 4 ) can catalyze O 2 to realize about 70 % mineralization of bisphenol A (BPA, 100 mg/L) within 240 min at 80 ℃, while it is only about 50 % for HM-NiCo 2 O 4 . Density functional theory calculations and molecular dynamics simulations show that PTFE indeed can enhance O 2 transfer and salt resistibility of HM-NiCo 2 O 4 . HO•, O 2 •- , and 1 O 2 all contribute to the degradation of BPA in presence of O 2 . These reactive oxygen species generate based on Mars-van Krevelen mechanism.

Constructing Ni–Co PBA derived 3D/1D/2D NiO/NiCo2O4/NiMn-LDH hierarchical heterostructures for ultrahigh rate capability in hybrid supercapacitors

Dongyan Gao,Renning Liu,Dandan Han,Pengcheng Xu,Ping Wang,Yen Wei

Engineering hierarchical heterostructure materials has been recognised as a challenging but prepossessing strategy for developing hybrid supercapacitors. Thus, a Ni–Co PBA derived 3D/1D heterostructure NiO/NiCo2O4 based layered double hydroxide on carbon cloth (CC/NiO/NiCo2O4/NiMn-LDH) as a battery-type electrode was successfully designed via a controllable hydrothermal method. The 3D Ni–Co PBA nanocubes served as scaffolds, providing more space for the nickel-cobalt precursors to grow and then calcine to form a continuous conductive layer of 3D/1D CC/NiO/NiCo2O4. Subsequently, 2D ultrathin NiMn-LDH nanosheets were uniformly anchored on 3D/1D NiO/NiCo2O4, resulting in a unique hierarchical structure that effectively addressed the restacking issue and dead volume of NiMn-LDH, contributing to increased charge and electron transport rates, which promoted the reaction kinetics. Benefiting from abundant interfaces with the open channels of the nanoarchitecture, the CC/NiO/NiCo2O4/NiMn-LDH electrode showed an exceptional specific capacity of 1593.0 C g−1 at 1 A g−1 and a desirable rate performance of 92.9% at a current density of 8 A g−1. Surprisingly, HSC devices can achieve an ideal specific energy of 44.28 W h kg−1 at a specific power of 108.22 W kg−1 with 97.59% cycling durability after 10 000 consecutive charge/discharge cycles. These remarkable properties indicate that the designed novel hierarchical heterostructure electrode has great potential for broad applications in electrochemical energy storage systems.

Enhanced Photocatalytic CO2 Reduction over Ni-doped Bi4O5Br2/NiCo2O4 Heterojunction: Synergistic Enhancement Effect between Spin Polarization and Built-in Electric Field

Zhixiong Yang,Bo Hu,Xiaotian Wang,Dmitry Selishchev,Gaoke Zhang

The development of high-performance photocatalysts is crucial for enabling efficient CO2 conversion in photocatalytic systems. Here, we developed a novel heterojunction (N-BON) composed of Ni-doped Bi4O5Br2 and NiCo2O4 for CO2 photoreduction with the help of simulated sunlight. The optimized 21N-BON composite exhibited the highest activity, producing 18.66 μmol·g–1·h–1 of CO with a selectivity of 95.7%, which represents a remarkable 2.15-fold and 4.75-fold increase in CO yield compared to the Bi4O5Br2/NiCo2O4 heterojunction and Ni-doped Bi4O5Br2, respectively. Photoelectrochemical testing, photoluminescence analysis, and theoretical calculations demonstrated that the enhanced performance of the 21N-BON composite is attributed to improved photogenerated carrier separation, driven by the synergistic effects of Ni-doping-induced spin polarization and the built-in electric field from heterojunction construction. Additionally, theoretical calculations and in situ DRIFTS analyses was used to clarify the CO2 reaction mechanisms on the photocatalyst surface, showing that Ni doping improved CO2 adsorption and promoted the formation of key reaction intermediates. This study offers important guidance for developing advanced photocatalysts for solar-driven CO2 reduction, contributing to sustainable energy solutions.