International Journal of Electrochemical Science
·
2023
·
IF 1.5
Zhe Li,Chun-yong Zhang,Hao-yu Wang,Lin Zhu,Hai-tao Liu,Li Shu,Ying-pin Weng
Herein, a simple hydrothermal method was used to synthesize cobalt hydroxide/nickel sulfide and cobalt foam (Co(OH) 2 /NiS@CF) composite electrode. By simply heating cobalt foam in the aqueous solution containing cobalt nitrate, nickel nitrate, and thiourea, Co(OH) 2 /NiS nano stereoscopic website was synthesized on Cobalt foam. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and electrochemical tests were used to characterize these composite electrodes. When the molar ratio of Co(NO 3 ) 2 ·6H 2 O to Thiourea of 4:5, Co(OH) 2 /NiS@CF exhibits excellent performance under these tests. The specific capacitance was 1260 F/g at 1.0 A/g. The composite electrode had 92.3% capacitance retention after 2000 charge-discharge cycles at 1.0 A/g.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Yunqing Pi,Peng Zhao,Lingjia Ma,Yangdan Cao,Huiqing Gao,Shuying Dong,Jianhui Sun
The Co(OH) 2 /reduced graphene oxide hybrids (Co(OH) 2 /rGO) was prepared and used as catalyst to enhanced heterogeneous activation of Oxone for the decomposition of Levofloxacin (LVF). The Co(OH) 2 /rGO composites with different Co(OH) 2 loading have been successfully synthesized, where the sample contain 20% Co(OH) 2 exhibited superior activation, attributing to the synergistic effect between Co(OH) 2 and rGO. Meanwhile, the effects of some important reaction parameters on the decomposition of LVF by Co(OH) 2 /rGO/Oxone process were investigated. The results indicated that the decomposition rate of LVF(>94.5%) was increased with the increasing of Oxone concentration, and 20% Co(OH) 2 /rGO dosage neutral pH. Moreover, the Co(OH) 2 /rGO catalyst showed high activity and stability during the repeated experiments.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 10
·13941-13947
·
IF 2.478
Liu Ying,Cao Bo,Zhang Xu,Luo Rong,Luo Chunhua,Lin Hechun,Peng Hui
Layered Co(OH) 2 has been regarded as a potential candidate for pseudocapacitor electrode material, but it is limited by its poor conductivity and low surface area. Herein, carbonated multi-walled carbon nanotubes (MWCNTs-COOH) were used to improve the conductivity of α-Co(OH) 2 nanocomposites. α-Co(OH) 2 nanoflowers were successfully grown and tangled with MWCNTs-COOH to form a randomly oriented network structure mediated by ammonia using water-methanol as co-solvent at room temperature. The capacitance performances of the obtained α-Co(OH) 2 @MWCNT-COOH composites were investigated to find that MWCNT-COOH improved the specific capacitance efficiently. Especially, in the presence of 20% in mole of MWCNT-COOH, the composite gave rise to the high specific capacitance of 1027 F/g at the current density of 2 A/g with good cycle stability, whose specific capacitance remained 78% of its original even after 5000 cycles at 30 A/g current. The large surface area and strengthening the conductivity of the composites lead to the improvement of efficiency in charge/discharge process.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Chunyan Fan,Xuxin Song,Yao Tang,Zehao Zang,Yangyang Ren,Lanlan Li,Xiaofei Yu,Xiaojing Yang,Zunming Lu,Xinghua Zhang
Designing catalysts that simultaneously optimize both hydrogen and oxygen evolution reaction (HER and OER) emerges as a critical materials challenge. Co(OH)₂ is recognized as an effective OER electrocatalyst, but the low HER activity limits its application in overall water splitting. In this work, we synthesized sulfur (S) and selenium (Se) doped Co(OH) 2 catalysts with significantly enhanced HER activity using an electrochemical deposition method. The S-Co(OH) 2 and Se-Co(OH) 2 catalysts own low HER overpotentials of 48 mV and 59 mV at 10 mA cm −2 . And they require 1.56 V and 1.64 V at the same current density for water splitting, the sustain stable performance for > 100 h at current densities (100 mA cm −2 ) show their practical durability. Density Functional Theory (DFT) calculations and experimental results reveal that non-metal doping induces electronic reconfiguration of Co and optimizes the ΔG H* value for intermediate formation, thus accelerating hydrogen generation and enhancing the intrinsic HER activity. This work presents an effective strategy for incorporating non-metal elements into transition metal-based catalysts, and provides insight to boost HER intrinsic activity and achieve bifunctional catalytic performance for water splitting.
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ADVANCED MATERIALS
·
2025
·
IF 26.8
Anquan Zhu,Heng Liu,Lulu Qiao,Bin Liu,Kunlun Liu,Chuhao Luan,Kai Liu,Yin Zhou,Dewu Lin,Guoqiang Gan,Jiapei Li,Guo Hong,Wenjun Zhang
The electrochemical nitrate reduction reaction (eNO 3 RR) is widely recognized as a promising strategy for sustainable ammonia production and supporting the nitrogen cycle. However, its advancement is impeded by complex behavior of reaction intermediates and the inevitable reconstruction of precatalysts. To address these challenges, the generation and utilization of active hydrogen (*H) are strategically managed by tailoring the RuO 2 /Co 3 O 4 precatalyst and optimizing the electrolyte composition (OH − and NO 3 − concentration), thereby selectively enhancing ammonia formation. Consequently, the in situ reconstructed RuO 2 /Co(OH) 2 catalyst achieves an impressive ammonia yield of 35.9 ± 0.9 mg h −1 cm −2 and a Faradaic efficiency (FE) of 98.1 ± 2.6% at −0.3 V versus RHE. Furthermore, the catalyst shows significant potential for applications in nitrate-rich wastewater treatment and rechargeable Zn-NO 3 − batteries, maintaining stable operation for over 260 hours at 1 mA cm −2 with only a 6 mV increase in the potential window. Mechanistic studies reveal that electron-rich RuO 2 facilitates *H generation through water dissociation, which subsequently migrates to Co(OH) 2 to hydrogenate nitrogenous intermediates, selectively producing ammonia. This study highlights the importance of designing efficient catalytic systems that address both precatalyst reconstruction and the complexities of reactant and intermediate conversion in electrolytes, which are essential for managing the intricate electron and proton transfer processes involved in eNO 3 RR.
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PubMed
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ACS Nano
·
2023
·
IF 17.1
Chuansheng He,Linlin Yang,Xiaohui Peng,Shangheng Liu,Jia Wang,Chengyuan Dong,Delin Du,Leigang Li,Lingzheng Bu,Xiaoqing Huang
Thickness regulation of transition metal hydroxides/oxides nanosheets with superior catalytic properties represents a promising strategy to enhance catalytic performance, but it remains an enormous challenge to achieve precise control, especially when it comes to the ultrathin limit (several atomic layers). In this work, a facile strategy of alkylamine-confined growth is proposed for the synthesis of thickness-tunable metal hydroxide/oxide nanosheets. Specifically, ultrathin cobalt hydroxide and cobaltous oxide hybrid (Co(OH)2-CoO) nanosheets (Co–O NSs) with a thickness in the range of 2–6 nm (5–13 atomic layers) are synthesized by using alkylamines with different carbon chain lengths as the ligand to modulate vertical coordination ability. Co–O NSs with a thickness of 2 nm (Co–O NSs-2 nm) exhibit excellent oxygen evolution reaction (OER) performance with an overpotential of 278 mV at 10 mA/cm2. The maximized number of active sites including oxygen vacancies, optimal adsorption strength, and the highest electrical conductivity are considered as the potential factors contributing to the excellent OER performance of Co–O NSs-2 nm. This work holds great significance for the precise thickness-tunable synthesis of transition metal layered hydroxide nanosheets with modulated and improved catalytic performance.
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ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Chunyan Fan,Zehao Zang,Xiang Li,Junfang Zhang,Ping Yang,Lanlan Li,Xiaofei Yu,Xiaojing Yang,Zunming Lu,Xinghua Zhang
Transition metal hydroxides have superior oxygen evolution reaction (OER) activity but poor hydrogen evolution reaction (HER) performance, which greatly limits the water splitting for hydrogen production. Herein, copper modification of sulfur doped Co(OH) 2 hybrid catalyst (Cu@S-Co(OH) 2 ) was prepared by one-step of electrodeposition method which can serve as efficient hydrogen evolution reaction catalyst. In the presence of sulfur and copper, Cu@S-Co(OH) 2 hybrid catalyst exhibits the best catalytic activity, showing ultralow overpotential of 42 mV at a current density of 10 mA cm −2 . Compared with Co(OH) 2 , the overpotential is improved by nearly 100 mV as well as enhanced stability. In addition, the active site poison experiments proved that the active center is cobalt metal. Combined with the adsorption strength of the catalyst for OH and H species, it is considered that both S and Cu can enhance the adsorption of OH for Co(OH) 2 , while S is contributed to the adsorption of H, and Cu can promote the desorption of H. This work provides a facile method and new insight to enhance the HER activity for transitional metal hydroxides via metal and non-metallic elements co-modulation.
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DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 22
·8832-8839
·
IF 4.569
Yihao Gao,Jie Bai,Tianning Zhou,Yaqiong Gong
In recent years, Co-based metal–organic frameworks (Co-MOFs) have received significant research interest because of their large specific surface area, high porosity, tunable structure and topological flexibility. However, their comparatively weak electrical conductivity and inferior stability drastically restrict the application of Co-MOFs in the synthesis of electrocatalysts. In this study, ZIF-67 was grown on nickel foam by a room temperature soaking method, and then Ir–Co(OH)2@ZIF-67/NF was assembled by a hydrothermal method. The prepared Ir–Co(OH)2@ZIF-67/NF nanosheets exhibit remarkable conductivity, larger electrochemical active surface area and wider electron transport channels. Only ultralow overpotentials of 198 mV, 263 mV, and 300 mV were needed for Ir–Co(OH)2@ZIF-67/NF to reach the current densities of 10 mA cm−2, 50 mA cm−2, 100 mA cm−2, meanwhile, no obvious degradation of the current density at 10 mA cm−2 was observed for about 16 h. This work may provide a promising strategy for developing high-performance MOF-derived materials as electrocatalysts for the OER under alkaline conditions.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 36
·16705-16713
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IF 3.591
Xue Meng,Li Yan,Maobin Wei,Tao Wang,Ting Xu,Yongsheng Yan,Shihan Cheng
The developed peroxydisulfate (PDS) activation for removing pollutants is a significant technology. Here, a Co(OH)2/Cu2O composite was synthesized and used to activate PDS for tetracycline (TC) degradation. Covering the surface of Cu2O with Co(OH)2 could improve the stability of the material, reactive active sites, and electron transfer efficiency of the catalyst. Thus, Co(OH)2/Cu2O composite exhibited excellent performance in terms of degrading the TC pollutant, and in the Co(OH)2/Cu2O/PDS system, the removal rate of TC could reach 98% within 30 min. Moreover, the effect of pH value, PDS dosage, and TC concentration on the degradation efficiency of TC was systematically studied. According to free radical quenching experiments, the possible mechanism of TC degradation over the Co(OH)2/Cu2O/PDS system was proposed. This work provided a research basis for the use of metal oxides for PDS activation in environmental treatment.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Xudan Li,Hanwei He
Cobalt hydroxide nanosheets/ruthenium oxide (Co(OH) 2 /RuO 2 ) nanocomposite on nickel foam was successfully synthesized via a simple electrodeposition process as an advanced supercapacitor electrode material. The microscopy studies reveal that RuO 2 nanoparticles are loaded uniformly on interconnected Co(OH) 2 nanosheets forming a three-dimensional (3D) network. The performance optimization of composite is come true through adjusting deposition time of RuO 2 nanoparticles. The electrochemical tests indicate that the optimized Co(OH) 2 /RuO 2 nanocomposite displays excellent super-capacitive properties. The specific capacitance is up to 2168 F g −1 as the current density is 1 A g −1 . Compared with the pure Co(OH) 2 and RuO 2 , the capacitance of the Co(OH) 2 /RuO 2 composite increases by 57% and 80%, respectively. The capacitance maintains at 86.0% after 5000 charging and discharging loops at the constant current density of 5 A g −1 , while the pure Co(OH) 2 only maintains 71.7% of the original capacitance after 5000 loops. The asymmetric capacitor assembled using Co(OH) 2 /RuO 2 nanocomposite as positive electrode and activated carbon (AC) as negative electrode exhibits a high energy density of 58.4 W h kg −1 at a power density of 1.2 kW kg −1 . The good pseudocapacitance behavior of the Co(OH) 2 /RuO 2 composite is mainly in virtue of the good synergies between Co(OH) 2 and RuO 2 insuring large surface area, rich electrochemical reactive sites, the short diffusion pathways of ions and good electroconductivity during the charge-discharge process.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2015
·Vol. 78
·期 2
·293-298
·
IF 1.532
Cui Hongtao,Ma Wenle,Wang Li,Xue Junying
Abstract
In this work, α-Co(OH) 2 monolayer nanosheets were prepared by an intercalation agent-free route utilizing a precipitation reaction between epoxide and aqueous complexes of cobalt ions ([Co(H 2 O) 6 ] 2+ ). The protonation and the following ring-opening reaction of epoxide promoted the hydrolysis of [Co(H 2 O) 6 ] 2+ , leading to the formation of α-Co(OH) 2 nanosheets. The obtained nanosheets were then exfoliated to monolayer nanosheets in formamide under ultrasonic vibration. A possible exfoliation mechanism is proposed for the exfoliating process of α-Co(OH) 2 nanosheets. The water molecules incorporated in the layered structure of α-Co(OH) 2 are considered to be the key medium for the layer exfoliation. It seems that the water molecules coordinated with the cobalt ions weakened the interlayer interaction. Therefore, the extraction of water molecules by formamide readily broke the interlayer connection in α-Co(OH) 2 , resulting in the exfoliation of nanosheets. Graphical Abstract α-Co(OH) 2 monolayer nanosheets were prepared by an intercalation agent-free route utilizing a precipitation reaction between epoxide and aqueous complexes of cobalt ions ([Co(H 2 O) 6 ] 2+ ).
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Changming Zhang,Zhihao Liu,Yongjin Zou,Fen Xu,Lixian Sun,Zhicong Hu,Sensen Yu,Cuili Xiang
Spinel-type materials are attracting great attention as potential electrocatalysts for the hydrogen- and oxygen-evolution reactions. However, their inherent catalytic activities are not on par with those of precious-metal catalysts, and their poor stabilities continue to constrain their rapid development. In this study, we fabricated Zr-CuCo 2 S 4 nanowires and Co(OH) 2 nanosheet–nanowires using electrochemical methods, resulting in lattice defects, sulfur vacancies, and more exposed active sites that catalyze the hydrogen- and oxygen-evolution reactions. DFT calculations revealed that sulfur vacancies enhance intrinsic activity, while Zr doping reduces the energy barrier for H*–OH* adsorption, promotes the formation of additional sulfur vacancies, and modulates active-site Cu/Co valence states, which greatly enhances water-dissociation and H*-adsorption kinetics. Consequently, Zr-CuCo 2 S 4 /Co(OH) 2 requires low overpotentials of 88 and 208 mV, respectively, to support highly stable alkaline hydrogen- and oxygen-evolution reactions at 10 mA cm −2 . This study provides a rational strategy for designing low-cost spinels for green and clean energy.
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