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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DOI
高影响因子
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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DOI
PubMed
高影响因子
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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高影响因子
IONICS
·
2019
·Vol. 25
·期 11
·5485-5494
·
IF 2.289
Wang Xiaoqing,Tian Songran,Zhang Xiaoqing,Li Guoyan,Liu Ying,Chen Botao,Cheng Bowen
A 3D Ni 3 S 2 @Mn-Co-OH/NF cross-linked nanosheet heterostructure composite electrode has been successfully fabricated by a facile two-step hydrothermal method. The as-prepared Ni 3 S 2 @Mn-Co-OH/NF composite electrode exhibits a high capacitance (3163 F g −1 at a current density of 3 mA cm −2 ), a superior rate performance (2071 F g −1 at a current rate of 30 mA cm −2 ), and stable cycling property (maintaining 96.6% of the initial capacitance after 4000 cycles at a current rate of 10 mA cm −2 ). This excellent electrochemical performance can be ascribed to the unique cross-linked nanosheet heterostructure formed directly on Ni foam current collector and the synergistic effect between Mn-Co-OH and Ni 3 S 2 of the composite electrode.
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高影响因子
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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高影响因子
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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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Jian Zhang,Jia-Fang Xie,Jie-Jie Chen,Wen-Wei Li,Jia-Cheng E. Yang,Yu-Ming Zheng,Han-Qing Yu
Heterogeneous peroxymonosulfate (PMS) activation is of great potential for sustainably degrading antibiotics included emerging contaminants from water. However, developing synthetic metal catalysts with incompatible mass transfer and optimized metal sites to effectively enable low-levels PMS activation and antibiotics removal is challenging. Herein, a protein-like Co catalyst of spatially hierarchical hydrophilicity is synthesized by constructing flower-like Mg/Al layered double hydroxide (LDH) on super-active carbon (AC) to disperse thin-layer Co(OH) 2 along the edge of LDH. The resulting AC-LDH@Co(OH) 2 catalyst demonstrates an impressive antibiotic removal of ≈80% within 15 s and turnover frequency of 45.72 min −1 based on catalyst mass by activating 0.075 mM PMS, surpassing single-atom catalysts included reports. In a fixed-bed reactor with secondary wastewater effluent, AC-LDH@Co(OH) 2 realizes complete removal of norfloxacin for 66 h with neutral effluent pH and negligible metal leaching. Experiments combined with theoretical computations reveal that the protein-like complex not only accelerates transfer of low-levels hydrophilic PMS and hydrophobic antibiotics, but also stably confines Co sites with regulated electronic structure for multiply reactive oxygen species generation.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Mengyin Liao,Chao Wang,Xuanhua Zhang,Chao Luan,Wenyuan Xu,Zhongyi He
Novel Pt/Co(OH)2-NiO/C catalysts based on carbon black were successfully synthesized using the hydrazine hydrate reduction method and galvanic replacement strategies. They were subsequently tested for their activity in the electrocatalytic oxidation of methanol. It was observed that the peak current density of Pt/Co(OH)2-NiO/C (8.29 A mg-1Pt) was 22.4 times higher than that of commercial Pt/C-JM (0.37 A mg-1Pt). The electrocatalytic activities and durabilities of the synchronously synthesized Pt/Co(OH)2-NiO/C catalysts were significantly better than those of PtCo/C, PtNi/C, and PtCoNi/C-X (X = 200, 400, 600) catalysts synthesized by calcination in Ar at different temperatures. The reason is that the highly dispersed Pt helps to expose more active sites on the catalyst surface, and the addition of Co(OH)2 and NiO alters the electron density of Pt, which reduces the adsorption of intermediate CO, attenuates the toxic effect, and enables more efficient oxidation of methanol.
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高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2020
·Vol. 22
·期 2
·1-12
·
IF 2.132
Sun Xueying,Li Siqi,Liu Rongmei,Sun Xiulun,Liu Xinjie,Li Anran,Li Wen
In this work, we designed a simple hydrothermal synthetic method for a ZnCo-PBA@α-Co(OH) 2 nanosphere@nanosheet material with good electrochemical properties. The obtained material had a specific capacitance of 423.92 F g −1 at 1 A g −1 and a cycling retention ratio of 78.48% after 1000 cycles at 5 A g −1 . A hybrid supercapacitor device (ZnCo-PBA@α-Co(OH) 2 //AC) assembled with activated carbon as the negative electrode had a specific capacitance of 122.4 F g −1 at 1 A g −1 , a cycling retention rate of 73.53% after 5000 cycles at 5 A g −1 , and a very high energy density of 49.13 Wh kg −1 at power density of 1734.0 W kg −1 . The significantly improved electrochemical performance of the ZnCo-PBA@α-Co(OH) 2 nanocomposites can be attributed to the positive synergistic effects of the porous structure of the PBA material and the large specific surface area of the α-Co(OH) 2 nanosheets, on the ion permeability and number of active sites in the reinforcing material; thus, this composite is a potential material for use in future energy storage systems.
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高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Ying Wu,Min Li,Wenhui Fang,Yutao Cao,Shixian Xin,Hong Zhao
Electrochemical water splitting is a promising method for hydrogen production but is restricted by sluggish oxygen evolution reaction (OER), so we propose to replace OER with the thermodynamically preferred glucose oxidation reaction (GOR) to reduce the supply voltage. Herein, hollow RuV-Co(OH) 2 arrays have been fabricated by the hydrothermal method of sacrificing ZIF-67 to codope vanadium (V) and ruthenium (Ru). Electrochemical studies show that RuV-Co(OH) 2 has excellent hydrogen evolution reaction (HER) activity with a low overpotential of 77 mV at the current density of 10 mA cm −2 (η 10 = 77 mV) and good GOR activity. Density functional theory (DFT) calculations indicate that V and Ru tune the electronic structure of RuV-Co(OH) 2 , greatly increasing the density of the active sites. Moreover, RuV-Co(OH) 2 assembled glucose-assisted hydrogen evolution cell exhibits a battery voltage of 1.42 V for a current density of 10 mA cm −2 , a significant reduction of 240 mV compared to overall water splitting along with higher-value glucose oxidation products. Furthermore, RuV-Co(OH) 2 exhibits outstanding stability. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate that RuV-Co(OH) 2 has superior mechanical stability. This work opens up a new approach to designing novel bifunctional electrocatalysts for energy-saving H 2 production and valuable coproductions.
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高影响因子
DIAMOND AND RELATED MATERIALS
·
2025
·
IF 5.1
Chenjie Liu,Yijin Wang,Wenlong Xu,Ming Zhou,Fuliang Meng,Xianfeng Meng
In light of electromagnetic pollution caused by the excessive or unregulated use of electromagnetic waves (EMWs), there is an urgent requirement to identify economical EMWs absorption materials. However, the facing challenge lies in the precise design of microstructure and the controlled tuning of electromagnetic parameters. Herein, natural cottonwood fiber was converted into carbon fiber (CF) through optimized pyrolysis, followed by the synthesis of CFs@Co 3 O 4 /Co(OH) 2 composites via in situ hydrothermal method. Ingenious structural design, multi-faceted synergy and heterogeneous interfaces endowed the CFs@Co 3 O 4 /Co(OH) 2 composites with exceptional impedance matching and electromagnetic loss, showing outstanding EMWs absorption ability. The CFs@Co 3 O 4 /Co(OH) 2 sample (CF S @Co-25) with 2.5 mm thickness displayed a maximum reflection loss ( RL max ) of −78.7 dB and an effective absorption bandwidth ( EAB ) of 9.9 GHz. At 3.0 mm matching thickness, the impedance matching value ( Z ) reached 0.99, with an RL max of −105.3 dB. This work offers a scalable and economical approach to developing high-performance carbon-based EMWs absorbers.
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高影响因子
Journal of Physical Chemistry C
·
2019
·
IF 4.309
Xueyang Song,Li Huang,Wenxue He,Chengyong Liu,Fengchun Hu,Yong Jiang,Zhihu Sun,Shiqiang Wei
Electronic metal–support interactions (EMSIs) have opened a new way to tailor the electronic and catalytic properties of supported catalysts. Herein, we demonstrate the EMSIs between Pt nanoparticles and Co(OH)2 flakes grown on SiO2 and show its beneficial effect on enhancing the CO oxidation activity. The EMSI characteristics of the Pt–Co(OH)2/SiO2 catalyst are identified by in situ X-ray absorption fine structure (XAFS) spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and transmission electron microscopy. Quantitative XAFS analysis reveals the presence of metallic-like Pt–Co bonds. The formation of Pt–Co intermetallic bonds allows for electron donation form Co to Pt, leading to the negative charging of the Pt atoms as evidenced by reduced Pt 2p-to-5d electron-transition intensity detected by XAFS spectroscopy and the emergence of a CO adsorption band at 2063 cm–1 in DRIFTS. The significance of EMSIs is manifested by comparing the CO oxidation activity over the Pt–Co(OH)2/SiO2 and Pt/SiO2 catalysts with similar Pt loadings. Pt–Co(OH)2/SiO2 is superior to Pt/SiO2 in both the apparent activation energy (19 vs 64 kJ/mol) and the turnover frequency (0.03 vs 0.003 s–1 at 37 °C). The enhanced activity is attributed to the negative charging of Pt, which downshifts the d-band center and reduces the CO adsorption strength.
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高影响因子
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