ENERGY & FUELS
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2021
·
IF 3.605
Zhihui Xu,Xuelei Li,Shishuai Sun,Zepeng Wei,Hongguo Li,Shougen Yin
The synergistic effect of the electrochemical double-layer and pseudocapacitance electrode materials has been extensively used to improve the performance of composite electrodes for supercapacitors (SCs). However, the energy density of SCs is still unsatisfactory for practical utilization. Herein, a C-NiCo2O4/C@Ni–Co–S electrode is ingeniously devised through coupling the interior of 0D/2D carbon-modified NiCo2O4 and the external sheath of Ni–Co–S nanosheets. The 0D carbon quantum dot doping can effectively avoid the agglomeration of NiCo2O4 nanoparticles and improve the electronic conductivity. 2D carbon as the intermediate layer can ameliorate the physical/chemical stability of the electrode. Ni–Co–S nanosheets can improve the area-specific capacitance of the electrode and thus enhance the energy density of the device. As expected, the C-NiCo2O4/C@Ni–Co–S electrode delivers an outstanding specific capacitance of 2396 F g–1 (7.9 F cm–2) at 3 A g–1 and excellent cycling stability (92% after 10 000 cycles). Furthermore, a quasi-solid-state asymmetric supercapacitor (ASC) using C-NiCo2O4/C@Ni–Co–S as positive electrode and active carbon (AC) as negative electrode exhibits a high energy density of 95 Wh kg–1 at 0.9 kW kg–1 and an excellent cycle performance. Our work reveals that this reasonable structure design is very effective for achieving a high-performance positive electrode for practical SC applications.
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Catalysts
·
2021
·Vol. 11
·期 4
·463
·
IF 4.146
Zhenglong Yang,Yan Cui,Pengxiang Ge,Mindong Chen,Leilei Xu
The Ni-based catalysts have a wide range of industrial applications due to its low cost, but its activity of CO2methanation is not comparable to that of precious metal catalysts. In order to solve this problem, Ni-based mesoporous Ce0.8Zr0.2O2solid solution catalysts doped with rare earth were prepared by the incipient impregnation method and directly used as catalysts for the methanation of CO2. The catalysts were characterized systematically by X-ray powder diffraction (XRD), N2physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), H2temperature programmed reduction (H2-TPR), CO2temperature programmed desorption (CO2-TPD), and so on. The results show that Ni is highly dispersed in the mesoporous skeleton, forming a strong metal-skeleton interaction. Therefore, under the condition of CO2methanation, the hot sintering of metallic Ni nanoparticles can be effectively inhibited so that these mesoporous catalysts have good stability without obvious deactivation. The rare earth doping can significantly increase the surface alkalinity of catalyst and enhance the chemisorption of CO2. In addition, the rare earth elements also act as electron modifiers to help activate CO2molecules. Therefore, the rare earth doped Ni-based mesoporous Ce0.8Zr0.2O2solid solution catalysts are expected to be an efficient catalyst for the methanation of CO2at low-temperature.Keywords:Ni-based catalyst;mesoporous Ce0.8Zr0.2O2solid solution;rare earth doped;low-temperature catalytic activity;CO2methanation
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CHEMOSPHERE
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2021
·
IF 7.086
Fang Zhu,Siyi Zhou,Mengying Sun,Jianfeng Ma,Wei Zhang,Kunjie Li,Hao Cheng,Sridhar Komarneni
Mg doped Ni(OH) 2 was synthesized and investigated as an efficient material to activate persulfate (PS) for phenol degradation. The property of the Ni(OH) 2 material was enhanced by Mg doping as the removal efficiency of phenol was increased from 74.82 % in Ni(OH) 2 /PS system to 89.53 % in Mg-doped Ni(OH) 2 /PS system within 20 min. Such a high removal efficiency revealed that doping Mg into Ni(OH) 2 brings about more defects (oxygen vacancies), which facilitated the formation of more active species in the degradation process. The removal efficiencies of phenol increased with the increase of the initial pH from 3 to 11. The influences of Cl − , NO 3 − and HCO 3 − on the stability of the system were also studied and the results showed that removal rates of all systems in the presence of these different inorganic anions could reached about 90 % within 20 min. Based on the electron spin resonance (ESR) experiments, 1 O 2 , O 2 ·- , ·OH and SO 4 •− were identified as the active species in Mg-doped Ni(OH) 2 /PS system for phenol degradation and a degradation mechanism was proposed for this system. In addition, the as-prepared material retained its activation performance even after 3 repeated cycles.
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PubMed
高影响因子
NANOTECHNOLOGY
·
2021
·Vol. 32
·期 38
·385602
·
IF 3.874
Ximing Zhang,Jingyu Wang,Yang Fan,Hengdong Ren,Zhenying Liu,Yanfen Wang,Yin Liu,Hongcun Bai,Lingbing Kong
In this work, we prepared NiCo alloy/C with rhombic dodecahedron structure and superior microwave absorption performance by using ZIF-67 as the raw material. The rhombic dodecahedron NiCo alloy/C was with rough particles on the surface was photographed by field emission scanning electron microscopy. By adjusting the doping amount of Ni and the temperature of pyrolysis, improved the impedance matching of NiCo alloy/C. Specifically, NiCo alloy/C exhibits a minimum reflection loss of −65.48 dB at 13.48 GHz, while the thickness is 1.63 mm. Defects introduced in the Ni doping process and the special rhombic dodecahedral structure can cause multiple loss mechanisms. Therefore, this NiCo alloy/C composite has the potential to be a potential microwave absorber material with lightweight and high microwave absorption properties.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
·
IF 7.312
Yi Wang,Qingjie Ji,Jixiang Xu,Jun Wan,Lei Wang
In this study, N-doped porous carbon materials embedded with NiN x species (Ni@NC) were fabricated via the pyrolysis of Ni-doped zeolitic imidazolate frameworks-8 (ZIF-8) at the temperature of 900 °C. The obtained Ni@NC-1 catalyst exhibited excellent activity in activating the peroxydisulfate (PDS) that was used for removing tetracycline (TC). The catalytic system exhibited good stability, wide pH adaptation, and high resistance to the operational environment. It was supposed that NiN x species could attach to PDS and act as electron acceptors to receive the electrons for activating the PDS, thus generating highly reactive superoxide radicals (⋅O 2 − ) and singlet oxygen ( 1 O 2 ) species for rapid degradation of TC. The electron transfer and dissolved oxygen-derived ⋅O 2 − were also responsible for the degradation of TC. In addition, the Ni@NC-1/PDS system exhibited high efficiency for removing oxytetracycline, ciprofloxacin, or levofloxacin. The results of this study would promote the design of other MOFs-derived carbon-encapsulated metal species for efficiently activating persulfate to remove antibiotics from the wastewater.
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ChemSusChem
·
2021
·Vol. 14
·期 14
·2935-2942
·
IF 8.928
Jifang Zhang,Wanbing Gong,Huajie Yin,Dongdong Wang,Yunxia Zhang,Haimin Zhang,Guozhong Wang,Huijun Zhao
Graphical Keep it 100 : A facile immersion approach has been developed to grow ultrathin nickel hydroxide nanosheets, which show excellent performance as the anode for electrocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid with 100 % yield and essentially 100 % faradaic efficiency under a low potential within a short reaction time. Development of electrocatalysts that are capable of efficiently oxidizing biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) is critically important for production of degradable plastics via non-fossil routes. In this study, a facile and scalable immersion synthetic approach has been developed to grow ultrathin nickel hydroxide nanosheets in situ on commercial nickel foam (Ni(OH) 2 /NF) as an anode for the electrocatalytic oxidation of HMF to FDCA with complete HMF conversion, 100 % FDCA yield, and >99 % faradaic efficiency at 1.39 V (vs. RHE) within 90 min. Mechanistic studies reveal that the initial oxidation of HMF takes place at the carbonyl group and FDCA is generated through two further oxidation steps. Impressively, the synthesized Ni(OH) 2 /NF can also be used to electrocatalytically oxidize other alcohol/aldehyde-containing compounds to the targeted products in alkaline medium with 100 % yield and >94 % faradaic efficiency under a low oxidation potential of 1.39 V (vs. RHE) within short reaction times.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
·
IF 8.128
Bo Lv,Xuefan Feng,Xiaoping Xi,Xinyan Feng,Zhenyu Yuan,Yu Yang,Fuqin Zhang
Heterogeneously structured materials with supported precious metals , such as Pd, Pt, and Ru, as co-catalysts are important catalysts for efficient photocatalytic water splitting. However, the high costs and low reserves of precious metals have been an obstacle to their application in hydrogen production . In this work, the noble-metal-free Cd 0.3 Zn 0.7 S solid solution was designed and synthesized with an optimized molar ratio of Cd/Zn for the best visible light photocatalytic performance. In addition, a heterojunction hybrid material formed between the Cd 0.3 Zn 0.7 S and Ni(OH) 2 nanosheet was engineered to improve the utilization of light and to inhibit the recombination of holes and electrons. Ni(OH) 2 nanosheets assisted the transfer of the photoexcited electrons to participate in the reduction reactions which is critical for efficient and rapid catalytic hydrogen production. The photoelectrochemical property of the hybrid material was investigated with UV–vis absorption, photoluminance (PL) and electrochemical impedance spectroscopy measurements. The mechanism of the high-efficiency and low-cost photocatalytic hydrogen production was established by analyzing the hydrogen evolution kinetics. With the success of replacing precious metal with nickel-based surface heterostructure, this work is expected to provide a new type of photocatalyst for the application of photocatalytic hydrogen production.
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PubMed
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
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2021
·
IF 3.927
Ping Ma,Xianliang Li,Yuchi Zhang,Le Han,Yan Xu
In this work, hierarchical spinel-type semiconductors MGa 2 O 4 (M = Ni, Co) were successfully synthesized via a facile hydrothermal method and a subsequent calcination strategy. The phase compositions, microstructures, as well as the gas sensing performances of these isostructural corn-like MGa 2 O 4 (M = Ni, Co) architectures were comparatively and systematically investigated. The experimental results showed that the hierarchical corn-like NiGa 2 O 4 spinel exhibited the optimum selective triethylamine (TEA) sensing performance with a gas response value (R g /R a ) of 7.60 at 270 °C, and excellent long-term stability for at least one month. The TEA gaseous sensing properties of these materials were significantly influenced by the transition metal M(II) ions dominated at the octahedral sites of spinel, and the sensing mechanism involving the surface redox reactions between the active oxygen species and TEA gases, as well as the charge carrier hopping process and changes of conductivity were discussed. This work not only demonstrated the facile preparation of hierarchical corn-like spinel-based gas sensors with rich active sites, we also discovered that the gas sensing performances of MGa 2 O 4 (M = Ni, Co) can be decisively modulated by the transition metal M(II)-ions.
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 6
·064513
·
IF 4.316
Yunyi Xu,Wen Jin,Tingting Yu,Feng Wang,Xiaoyu Guo,Yiping Wu,Ye Ying,Ying Wen,Haifeng Yang
The development of durable and efficient anode electrocatalysts is crucial for direct methanol fuel cells. In this paper, polyaniline (PANI) microtubes are firstly prepared by removing the polystylene (PS) core from PANI coated electrospun PS. The catalyst of PtNi/PANI@rGO is built by two steps: graphene oxide (GO) is mixed with PANI microtubes to obtain PANI@GO and then PANI@GO is used as a support material to load PtNi nanoparticles by reductive reaction while GO is reduced into rGO. The morphology, electronic structure and chemical structure of the catalysts are characterized by SEM, TEM, XPS and Raman spectroscopy, respectively. The electrochemical analysis of electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometric measurement are performed to analyze the electrocatalytic performance. The electrochemical results indicate that as-synthesized PtNi/PANI@rGO has the high activity toward methanol oxidation, and its mass activity is 1.7, 1.3 and 4.1 times higher than that of PtNi/PANI, PtNi/rGO and commercial Pt/C catalysts, respectively. The PANI microtubes not only improve the electron transfer kinetic but also help avoid the accumulation of graphene layers. The doping of Ni into Pt changes the surface electronic structure to elevate the catalytic activity and helps effectively improve the resistance to CO poisoning.
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Journal of Energy Chemistry
·
2021
·
IF 9.676
Zhiguo Zhang,Hua Huo,Zhenjiang Yu,Lizhi Xiang,Bingxing Xie,Chunyu Du,Jiajun Wang,Geping Yin
Mn doping is deemed as a promising strategy to improve the electrochemical performance of the α-Ni(OH) 2 battery-type supercapacitor electrode. However, the internal structure evolution, the pathways and the dynamics of the proton/intercalated anion migration, as well as the functioning mechanism of Mn dopant to stabilize the layered structure during cycles remain unclear. Here, we unveil that irreversible oxidization of Mn 3+ at the initial CV cycles, which will remain as Mn 4+ in the NiO 2 slabs after the first oxidization to effectively suppress the phase transformation from α-Ni(OH) 2 /γ-NiOOH to β-Ni(OH) 2 /β-NiOOH and further maintain the structural integrity of electrode. With a synergistic combination of theoretical calculations and various structural probes including XRD and 2 H MAS solid state NMR, we decode the structure evolution and dynamics in the initial CV (cyclic voltammetry) cycles, including the absorption/desorption of hydrogen containing species, migration of intercalated anions/water molecules and the change of interlayer space. This present work elucidates a close relationship between doping chemistry and structural reliability, paving a novel way of reengineering supercapacitor electrode materials.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Fangyou Meng,Yuan Yu,Dongfeng Sun,Li Li,Songmin Lin,Luo Huang,Wenhui Chu,Shufang Ma,Bingshe Xu
A novel three-dimensional (3D) flower-like tungsten phosphide (WP 2 ) nanowire arrays catalyst in-situ grown on nickel foam (NF) is explored. Since this 3D nanostructured electrocatalysts (WP 2 NW/NF) can expose the abundant active sites, and promote electrolyte osmosis to shorten the electron transfer path, the WP 2 NW/NF electrode shows excellent electrocatalytic performance. The current densities of the 3D nanostructured WP 2 NW/NF electrode achieve 10 mA cm −2 at lower cell potential of 1.65 V for overall water splitting, revealing that this 3D nanostructured electrode possesses great application prospect in electrolysis of water to produce large-scale hydrogen and oxygen.
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Catalysis Science & Technology
·
2021
·Vol. 11
·期 7
·2471-2479
·
IF 6.119
Tianying Xie,Limei Cao,Wei Sun,Ji Yang
Severe conditions involved in hydrogen storage and transportation limit the practical applications of hydrogen denitration reaction. In this paper, we developed a new process that consists of methanol steam reforming inline hydrogen production coupled with denitration, which reduces the threshold use of hydrogen. The bifunctional CuZnOx–X–MnPdOz@Ni catalyst prepared in this paper could achieve inline hydrogen production through the CuOx center and reduce NOx by the MnPdOz center. The optimal CuZnOx–CeZrOy–MnPdOz@Ni candidate catalyst could maintain over 90% denitration efficiency under conditions: GHSV = 22 000 h−1 + nmethanol : nwater = 1 : 1.3 + 800 ppm NO at 150 °C. We conducted various characterization methods to reveal the valence state distribution of the promising catalyst. The experimental results indicated that the inline hydrogen selective catalytic reduction of NO is a promising strategy for green, efficient, and sustainable NOx control technology.
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