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Yuanchao Pang, Shuyang Zhang, Sheng Chen, Jin Liang, Mingyan Li, Dawei Ding, Shujiang Ding
The increasing demands for effective energy storage systems derived from low-cost and eco-friendly raw materials have aroused wide concern. In this contribution, we proposed nitrogen abundant amorphous micron-sized carbon ribbons (AMCRs) originated from biomass raupo as novel substrate due to their specific quasi two-dimensional morphologys and outstanding dispersion ability. Owing to the innate nitrogen atoms on the surface of AMCRs, ultrathin binary and ternary metal oxides (NiO, CoO, and NiCo2O4) nanosheets can be uniformly developed under benign conditions...
August 6, 2018: Chemistry: a European Journal
Xiaoqiang Du, Qibin Wang, Yu Li, Xiaoshuang Zhang
It is imperative to develop bifunctional electrocatalysts with good activity and stability for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this paper, a hierarchical NiCo2O4/Ni3S2 hybrid is synthesized by direct growth on nickel foam (NF) using co-precipitation and sulfuration as a general two-step method. When the NiCo2O4/Ni3S2/NF material is used as an electrode, it displays high activity and perfect stability for OER. A low overpotential of only 360 mV is obtained at 40 mA cm-2, comparable to the benchmark of IrO2 electrodes (330 mV overpotential at 40 mA cm-2), benefiting from the particular hybrid structure of NiCo2O4/Ni3S2/NF with large surface area and fast electron transfer...
July 31, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Nengneng Xu, Yixiao Cai, Luwei Peng, Jinli Qiao, Yu-Dong Wang, William M Chirdon, Xiao-Dong Zhou
Central to commercializing metal-air batteries is the development of highly efficient and stable catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this study, a composite catalyst with a unique interpenetrating network (denoted as NiCo2O4@MnO2-CNTs-3) was synthesized and exhibited better bifunctional activity (ΔE = 0.87 V) and durability than both Pt/C and Ir/C catalysts. The improved performance arises from three factors: (i) MnO2 promotes the ORR while NiCo2O4 facilitates the OER; (ii) carbon nanotubes improve the electronic conductivity; and (iii) the highly porous structure enables the adsorption-desorption of O2 and enhances the structural stability...
July 19, 2018: Nanoscale
Andrew Schranck, Randal Marks, Elon Yates, Kyle Doudrick
Cyclic voltammetry (CV) and in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were used to investigate the effect of major urine compounds on the electro-oxidation activity of urea using a nickel cobaltite (NiCo2 O4 ) catalyst. As a substrate, carbon paper exhibited better benchmark potential and current values compared with stainless steel and fluorine-doped tin oxide glass, which was attributed to its greater active surface area per electrode geometric area. CV analysis of synthetic urine showed that phosphate, creatinine, and gelatin (i...
July 17, 2018: Environmental Science & Technology
Yan Xing, Man Yang, Yunfeng Li, Yue Yu, Xianchun Liu, Zhan Shi
In this work, a series of three-dimensional porous flower-like zinc doped NiCo2O4 (ZNCO) nanostructures with different Zn doping level are successfully prepared by a facile solvothermal process without using any templets. The obtained products are characterized by various techniques, and their electrocatalytic performances are also assessed by oxygen evolution reaction (OER). According to the electrochemical characterization, it is demonstrated that ZNCO-0.15 (i.e Zn0.15Ni0.85Co2O4) nanoflowers show a lower overpotential, smaller Tafel slope, higher electrochemical active surface area (ECSA), as well as larger turnover frequency (TOF) value than those of Co3O4, NiCo2O4 and ZnCo2O4 NFs, indicating that introduction of optimal content of zinc ions plays an important role in enhancing electrocatalytic performances for OER...
June 12, 2018: Chemistry: a European Journal
X Luo, M Huang, D He, M Wang, Y Zhang, P Jiang
High electrical conductivity and the exposure to more active sites are crucial to boost the performance of a glucose sensor. A porous binary metal oxide nanoarray integrated on a binder-free 3D electrode is expected to offer a highly sensitive sensing platform. As a model, porous NiCo2O4 nanowire arrays supported on carbon cloth (NiCo2O4 NWA/CC) have been prepared and used for enzyme-free glucose sensing. NiCo2O4 NWA/CC shows larger effective surface area, superior electronic conductivity, and higher catalytic activity towards enzyme-free glucose sensing, with a linear range from 1 μM to 0...
May 29, 2018: Analyst
Hairong Xue, Hongjie Yu, Yinghao Li, Kai Deng, You Xu, Xiaonian Li, Hongjing Wang, Liang Wang
Control of structures and components of the nanoarray catalysts is very important for electrochemical energy conversion. Herein, unique NiCo2 O4 @MnO2 core-shell nanoarray with hollow NiCo2 O4 Cores and MnO2 flake shells is in situ fabricated on carbon textile via a two-step hydrothermal treatment followed by a subsequent annealing. The as-made nanoarray is highly active and durable catalyst for oxygen evolution reaction in alkaline media attribute to the synergetic effect derived from spatially separated nanoarray with favorable NiCo2 O4 and MnO2 compositions...
July 13, 2018: Nanotechnology
Hui Yuan, Jiantao Li, Wei Yang, Zechao Zhuang, Yan Zhao, Liang He, Lin Xu, Xiaobin Liao, Ruiqi Zhu, Liqiang Mai
Rationally generating oxygen vacancies in electrocatalysts is an important approach to modulate the electrochemical activity of a catalyst. Herein, we report a remarkable enhancement in oxygen reduction reaction (ORR) activity of NiCo2 O4 supported on hollow carbon spheres (HCS) achieved through generating abundant oxygen vacancies within the surface lattice. This catalyst exhibits enhanced ORR activity (larger limiting current density of ∼-5.8 mA cm-2 ) and higher stability (∼90% retention after 40 000 s) compared with those of NiCo2 O4 /HCS and NiCo2 O4 ...
May 16, 2018: ACS Applied Materials & Interfaces
Fen Cui, Yunpeng Huang, Le Xu, Yan Zhao, Jiabiao Lian, Jian Bao, Huaming Li
A 3D hierarchical NiCo2O4/PANI/MF composite foam with a macroporous 3D skeleton, a conductive PANI coating and highly electrochemically active NiCo2O4 nanosheets is synthesized as a lightweight and low-cost electrode material. Due to the collaborative contribution of all the components, the prepared composite foam exhibits excellent capacitive performances when incorporated into an asymmetric supercapacitor.
April 19, 2018: Chemical Communications: Chem Comm
Wei Wang, Jiqiu Qi, Yanwei Sui, Yezeng He, Qingkun Meng, Fuxiang Wei, Yunxue Jin
A facile method was utilized to convert a common biomass of walnut shells into activated porous carbon by carbonization and activation with nitricacid treatment. The obtained activated carbon (WSs-2) exhibited excellent electrochemical performance with high specific capacitance of 137 F · g-1 at 1 A · g-1 and super cycling performance of 96% capacitance retention at 5 A · g-1 after 5000 cycles. In addition, NiCo2O4 nanoneedle arrays with good electrochemical properties were successfully prepared by a simple hydrothermal method...
August 1, 2018: Journal of Nanoscience and Nanotechnology
Jie Zhang, Ruixia Chu, Yanli Chen, Heng Jiang, Ying Zhang, Nay Ming Huang, Hang Guo
Binder-free nickel cobaltite on a carbon nanofiber (NiCo2 O4 @CNF) anode for lithium ion batteries was prepared via a two-step procedure of electrospinning and electrodeposition. The CNF was obtained by annealing electrospun poly-acrylonitrile (PAN) in nitrogen (N2 ). The NiCo2 O4 nanostructures were then grown on the CNF by electrodeposition, followed by annealing in air. Experimental results showed that vertically aligned NiCo2 O4 nanosheets had uniformly grown on the surface of the CNF, forming an interconnected network...
March 23, 2018: Nanotechnology
Beibei Wang, Shaobo Cai, Gang Wang, Xiaojie Liu, Hui Wang, Jintao Bai
Hierarchical ultrathin NiCo2 O4 nanosheeets grown on uniform hollow carbon microspheres (HC@NiCo2 O4 ) are designed and fabricated by a solvothermal reaction followed with an annealing process. When evaluated as an anode for lithium ion batteries, the as-prepared HC@NiCo2 O4 microspheres exhibit excellent electrochemical performance (a high reversible capacity of 1015 mA h g-1 after 100 cycles at a current density of 0.1 A g-1 and a high capacity of 805 mA h g-1 even at a high current density of 0...
March 1, 2018: Journal of Colloid and Interface Science
Chun Chang, Lei Zhang, Chan-Wei Hsu, Xui-Fang Chuah, Shih-Yuan Lu
Mixed NiO/NiCo2 O4 nanocrystals grown in situ from the skeleton of a 3D porous nickel network (3DPNN) were prepared with a simple hydrothermal method followed by a low temperature calcination, exhibiting outstanding electrocatalytic efficiencies toward oxygen evolution reactions (OER). The 3DPNN was prepared with a novel leaven dough method and served as both the nickel source for growth of the mixed NiO/NiCo2 O4 nanocrystals and the charge transport highway to accelerate the sluggish kinetics of the OER. The mixed NiO/NiCo2 O4 nanocrystals exhibited pronounced synergistic effects to achieve a high mass activity of 200 A g-1 at the catalyst mass loading of 0...
January 10, 2018: ACS Applied Materials & Interfaces
Surya V Devaguptapu, Sooyeon Hwang, Stavros Karakalos, Shuai Zhao, Shiva Gupta, Dong Su, Hui Xu, Gang Wu
Spinel NiCo2 O4 is considered a promising precious metal-free catalyst that is also carbon-free for oxygen electrocatalysis. Current efforts mainly focus on optimal chemical doping and substituent to tune its electronic structures for enhanced activity. Here, we study its morphology control and elucidate the morphology-dependent catalyst performance for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Three types of NiCo2 O4 catalysts with significantly distinct morphologies were prepared using temple-free, Pluronic-123 (P-123) soft, and SiO2 hard templates, respectively, via hydrothermal methods followed by calcination...
December 27, 2017: ACS Applied Materials & Interfaces
Kavita Kumar, Lola Loupias, Christine Canaff, Sophie Morisset, Stéphane Pronier, Cláudia Morais, Aurélien Habrioux, Teko W Napporn, K Boniface Kokoh
This work reports on the facile synthesis and characterisation of a non-precious-metal bifunctional catalyst for oxygen reduction and evolution reactions (ORR and OER). A few-layer reduced graphene oxide-supported NiCo2 O4 catalyst is prepared using a rapid and easy two-step method of synthesis. It consists of the solvothermal poyl(vinylpyrrolidone)-assisted assembly of metal complexes onto few-layer graphene followed by a calcination step aiming at converting metal complexes into the spinel phase. Using this synthesis approach, the most active material demonstrates an outstanding activity towards the OER and ORR, making it one of the best bifunctional catalysts of these reactions ever reported...
February 5, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Lei Zang, Qiuyu Zhang, Li Li, Yike Huang, Xiaoya Chang, Lifang Jiao, Huatang Yuan, Yijing Wang
Lithium borohydride (LiBH4 ) with a theoretical hydrogen storage capacity of 18.5 wt % has attracted intense interest as a high-density hydrogen storage material. However, high dehydrogenation temperatures and limited kinetics restrict its practical applications. In this study, mesoporous nickel- and cobalt-based oxide nanorods (NiCo2 O4 , Co3 O4 and NiO) were synthesized in a controlled manner by using a hydrothermal method and then mixed with LiBH4 by ball milling. It is found that the dehydrogenation properties of LiBH4 are remarkably enhanced by doping the as-synthesized metal oxide nanorods...
January 4, 2018: Chemistry, An Asian Journal
Hao Tong, Shihong Yue, Liang Lu, Fengqiao Jin, Qiwei Han, Xiaogang Zhang, Jie Liu
To increase the volumetric and gravimetric capacitances of supercapacitors, a new class of electrode materials with high electrochemical activity and favorable structures is extremely desired. In this work, a hollow novel nitrogen-doped 3D elastic single-walled carbon nanotube sponge (NSCS) which is ultra lightweight with the lowest density of 0.8 mg cm-3 , and has a high open surface structure for electrolyte accessibility and excellent compressible properties as the electrode scaffold has been successfully fabricated by the pyrolysis method which could produce the carbon nanotube sponge easily on a large scale without high-cost and time-consuming processes...
November 9, 2017: Nanoscale
Kaibing Xu, Jianmao Yang, Junqing Hu
Hollow micro-/nanostructured electrode materials with high active surface area are highly desirable for achieving outstanding electrochemical properties. Herein, we report the successful synthesis of hierarchical hollow NiCo2 O4 nanospheres with high surface area as electrode materials for supercapacitors. Electrochemical measurements prove that such electrode materials exhibit excellent electrochemical behavior with a specific capacitance reaching 1229 F/g at 1 A/g, remarkable rate performance (∼83.6% retention from 1 to 25 A/g) and good cycling performance (86...
February 1, 2018: Journal of Colloid and Interface Science
Haibo Rong, Zhongqing Jiang, Xiaoning Tian, Yanmin Qin, Si Cheng, Fu Wang, Zhong-Jie Jiang
A facile template-free Ostwald ripening method is developed for the preparation of the reduced graphene oxide supported splode-like NiCo2 O4 hollow microsphere (SNHM/rGO). The graphene oxide used in the reaction mixture is found to play a crucial role in the formation of the SNHM/rGO. It promotes the formation of the NiCo-glycerol microspheres suitable for the Ostwald ripening to form the reduced graphene oxide supported hollow NiCo-glycerol microspheres, which is important for the subsequent calcination to form the SNHM/rGO...
February 1, 2018: Journal of Colloid and Interface Science
Yuxuan Liu, Yu Bai, Yu Han, Zhou Yu, Shimin Zhang, Guohua Wang, Junhua Wei, Qibing Wu, Kening Sun
The development of advanced earth-abundant electrocatalysts for hydrogen production is highly desirable. In this paper, we report the design and synthesis of a novel and highly efficient electrode of NiCo2 O4 nanoneedles decorated with FeCoNi layered ternary hydroxides supported on carbon cloth (FeCoNi-LTH/NiCo2 O4 /CC) by a facile and efficient two-step approach. It exhibits superior bifunctional catalytic activities for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media, due to the special structure and strong synergies...
October 25, 2017: ACS Applied Materials & Interfaces
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