NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 40
·19161-19167
·
IF 3.925
Peng Miao,Weixing Chen,Kailei Li,Weifeng Zhao,Jie Kong
Design of microwave absorbents with hierarchical interfacial structures has become an effective method to scatter microwaves. Metal/carbon composites derived from metal–organic frameworks (MOFs) have attracted considerable attention due to their tunable chemical composition and microstructure. We describe the facile synthesis of a Co/CoO/FeO/C nanocomplex employing Co(OH)2 on NH2-MIL-88B as the “sacrificial template” through one-step pyrolysis. The as-prepared flaky-like Co/CoO/FeO/C nanocomplex showed an effective absorption width of 4.7 GHz at 1.86 mm and a minimum reflection loss of −45.5 dB at 2.01 mm. Our study can aid design of a microstructural strategy for preparing high-performance microwave absorbents.
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高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 48
·18061-18068
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IF 4.39
Jiahui Guo,Xueqing Feng,Songrui Wang,Qikang Wu,Shanshan Lv,Yan Zhou,Han Li,Zheng Chen,Yuzhong Zhang
Novel hexagonal α-cobalt hydroxide nanosheets are synthesized through a 2-methylimidazole-induced hydrolysis strategy with cetyltrimethylammonium bromide (CTAB) as a surfactant. The weak alkaline environment provides favorable conditions for the formation of metastable α-Co(OH)2, while the same raw material will produce β-Co(OH)2 when a strong alkali solution is used. CTAB plays a vital role not only in hexagonal oriented growth, but also in the formation of the hydrotalcite-like structure of α-Co(OH)2 with high crystallinity. The crystallinity of both α- and β-Co(OH)2 is very poor without CTAB as a surfactant. The Co in this Co(OH)2−x layer presents most of the CoII and a small part of the CoIII, and the interlayer nitrate anion balances the positive charge of the host layer. The redox function produced by the CoII and CoIII of α-Co(OH)2 together with the large layer spacing jointly promotes the electron and mass transfer. The use of hydrazine hydrate for transfer hydrogenation involves the transport of protons and electrons produced by decomposition, and the rapid transport is bound to be conducive to the reduction process. Nitro compounds with varieties of functional groups can be smoothly reduced to the corresponding amines with high selectivity, when α-Co(OH)2 was used as a catalyst under mild conditions.
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高影响因子
Journal of Energy Storage
·
2021
·
IF 6.583
Weizhi Gong,Mingjun Wang,Yi An,Junli Wang,Liexing Zhou,Yi Xia,Chunjian Wang,Kun Dong,Cheng Pan,Rongfeng Zhou
Cycling stability and specific capacitance are two of important performance parameters for pseudocapacitive electrodes under frequent charging and discharging. Herein, we present a facile solvothermal approach to rationally design and fabricate chiffon-like and hydrotalcite-like α-Co(OH) 2 nanoflakes for extrinsic pseudocapacitive electrode, which exhibits linear galvanostatic discharge behavior and superior charge-storage performance, including high capacitance of 475 F g −1 at 1 A g −1 , excellent rate capability and superb cycling stability with capacitance retention of 93.9% after 10000 cycles at 10 A g −1 . The superior performance is mostly attributed to the good electrical conductivity and stable microstructure of the hydrotalcite-like α-Co(OH) 2 nanoflakes and the abundant redox active sites on the chiffon-like nanoflakes with short and facile electron transport. In addition, other α-Co(OH) 2 samples with different morphologies and size as contrast are prepared and discussed, indicating that the morphology/size design and optimization of the α-Co(OH) 2 could greatly improve the electrochemical energy-storage performance. The findings demonstrate that the chiffon-like and hydrotalcite-like α-Co(OH) 2 nanoflakes have a great practical application potential in long-life and high-performance supercapacitors . This study also presents a facile way to design and prepare nanoflake-like materials with adjustable lateral size and thickness from spherical morphology consisting of nanoflakes.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yangxin Rong,Yuan Chen,Jihua Zheng,Yan Zhao,Qiuping Li
Herein, a series of alpha-Co(OH) 2 /reduced graphene oxide (rGO) microfilms and film-based nanodevices were developed via a new scalable technique. Due to the unique hexagonal nanoplates of ultrathin alpha-Co(OH) 2 and the intrinsically conductive nature of rGO sheets, such thin films not only can improve the conductivity of alpha-Co(OH) 2 and prevent the re-stacking of alpha-Co(OH) 2 and rGO sheets but also short the transport routes of electrons and ions between the electrode and the electrolyte. The optimized alpha-Co(OH) 2 /rGO flexible electrode presents high specific capacitance (273.86 mF/cm 2 at 0.1 mA/cm 2 ), advanced rate capability, and excellent coulombic efficiency. Simultaneously, in-sandwich symmetric and asymmetric supercapacitors assembled with polyvinyl alcohol-KOH gel as the solid-state electrolyte achieved high areal and volumetric specific capacitances. Furthermore, a self-assembled planar alpha-Co(OH) 2 /rGO micro-supercapacitor (MSC) delivers high specific area capacitance (130F/cm 2 at 0.5 mA/cm 2 ) and excellent energy density (20 mWh/cm 3 @56 mW/cm 3 ), which are superior to most of the recently reported carbon-based and metal hydroxides/oxides/sulfides-based planar MSCs. Also, our planar MSC shows excellent cycling performance, good flexibility, and mechanical stability. This work promotes the syntheses of other two-dimensional metal hydroxides/rGO composite film for high-performance flexible micro-electronics.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Li-Wen Jiang,Yuan Huang,Bing-Bing Chen,Jian-Qiu Zhou,Hong Liu,Jian-Jun Wang
Hydrogen production via alkaline water electrolysis is of significant interest. However, the additional water dissociation step makes the Volmer step a relatively more sluggish kinetics and consequently leads to a slower reaction rate than that in acidic solution. Herein, we demonstrate an effective strategy that Co(OH) 2 can promote the Volmer process by accelerating water dissociation and enhance the electrocatalytic performance of CoP toward alkaline hydrogen evolution reaction . The Co(OH) 2 nanoplates are electrochemically induced in-situ generated to form a nanotree-like structure with porous CoP nanowires , endowing the hybrid electrocatalyst with superior charge transportation, more exposed active sites, and enhanced reaction kinetics. This strategy may be extended to other phosphides and chalcogenides and provide insight into the design and fabrication of efficient alkaline HER catalysts.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2023
·
IF 8.4
Zhijia Liao,Zhenyu Yuan,Hongliang Gao,Fanli Meng
In response to the pressing demand for acetic anhydride gas detection, this study introduces a novel gas sensor for precisely detecting acetic anhydride concentrations. The optimum conditions for the synthesis of cobalt hydroxyfluoride/cobalt oxide (CHFCO) heterojunctions with good acetic anhydride gas sensitivity were determined by carefully adjusting the calcination time, hydrothermal time and ammonium fluoride content. The best performing composite CHFCO sensor with porous rod particles was tested at 180 ℃ and achieved a response rate of 260 for 100 ppm acetic anhydride gas, with response and recovery times of 60 and 40 s, respectively. In comparison to other prepared sensors, the detection response for acetic anhydride was improved by a factor of 4.30–23.63. Moreover, the CHFCO sensor reliably detected acetic anhydride at a concentration of 500 ppb, exhibiting a response value of 1.56. Notably, the sensor demonstrated great selectivity, moisture resistance , and stability. The findings highlight the significant enhancements in gas-sensitive performance to acetic anhydride achieved by the abundant hydroxyl bonds on the surface of CHFCO heterojunction, the presence of fluorine ions , and the modulation of the band gap. These results provide valuable insights for the advancement of acetic anhydride gas sensors based on CHFCO heterojunction.
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高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2023
·
IF 8.7
Zuozhu Yin,Min Li,Zihao Li,Yuanting Deng,Mingshan Xue,Yuhua Chen,Junfei Ou,Sheng Lei,Yidan Luo,Chan Xie
Traditional membranes are inefficient in treating highly toxic organic pollutants and oily wastewater in harsh environments, which is difficult to meet the growing demand for green development. Herein, the Co(OH) 2 @stearic acid nanocellulose-based membrane was prepared by depositing Co(OH) 2 on the nanocellulose-based membrane (NBM) through chemical soaking method, which enables efficient oil/water mixtures separation and degradation of pollutants by photocatalysis in harsh environments. The Co(OH) 2 @stearic acid nanocellulose-based membrane (Co(OH) 2 @stearic acid NBM) shows good photocatalytic degradation performance for methylene blue pollutants in harsh environment, and has significant degradation rate (93.66%). At the same time, the Co(OH) 2 @stearic acid NBM with superhydrophobicity and superoleophilicity also exhibits respectable oil/water mixtures separation performance (n-Hexane, dimethyl carbonate, chloroform and toluene) under harsh environment (strong acid/strong alkali), which has an excellent oil-water mixtures separation flux of 87 L·m −2 ·h −1 (n-Hexane/water) and oil-water mixture separation efficiency of over 93% (n-Hexane/water). In addition, this robust Co(OH) 2 @stearic acid NBM shows good self-cleaning and recycling performance. Even though seven oil-water separation tests have been carried out under harsh environment, it can still maintain respectable oil-water mixture separation rate and flux. The multifunctional membrane has excellent resistance to harsh environments, oil-water separation and pollutant degradation can be performed even in harsh environments, which provides a convenient way to treat sewage under harsh conditions efficiently and has great potential in practical application.
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高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 24
·5809-5817
·
IF 9.125
Haidong Yang,Yu Long,Yan Zhu,Ziming Zhao,Ping Ma,Jun Jin,Jiantai Ma
The exploration of highly efficient nonprecious metal-based electrocatalysts for the oxygen evolution reaction (OER) is of great importance for potential applications in sustainable energy conversion. Recently, the layered metal hydroxide (LMH) family is receiving extensive research attention owing to its unique structural properties. However, the gained electrocatalytic performance of LMH-based catalysts for the OER is still far from the state-of-the-art requirements because of its finite number and poor reactivity of exposed active sites. In response, we synthesized crystal lattice distorted ultrathin cobalt hydroxide (denoted as CLD-u-Co(OH)2) nanosheets with a great number of efficient catalytic active sites through the introduction of Ga into ultrathin Co(OH)2, followed by a selective removal of Ga, denoted as the “introduction @ removal” process. As a result, the crystal lattice distortion confined inside CLD-u-Co(OH)2 generates abundant elongated Co–OOH bonds on exposed (10) facets serving as efficient catalytic active sites for the OER. Besides, the optimized amount of “introduction @ removal” of Ga (4 at%) allows for an exquisite balance between distortion engineering and electrical conductivity, synergistically. The as-prepared CLD-u-Co(OH)2 achieves an overpotential of 265 mV at a current density of 10 mA cm−−2, an unexpectedly small Tafel slope of 47 mV dec−−1, and a long-term stability (beyond 20 h) in basic media. It is mainly attributed to abundant catalytic active sites, robust reactivity per site, and good electrical conductivity. Furthermore, the green and sustainable engineering of crystal lattice distortion to improve the intrinsic electrocatalytic activity of CLD-u-Co(OH)2 nanosheets presented in this work may provide a promising strategy to design and synthesize newly highly efficient LMH-based electrocatalysts for the OER.
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 42
·6305-6313
·
IF 3.474
Abraham Adenle,De-Kun Ma,De-Peng Qu,Wei Chen,Shaoming Huang
The fabrication of hollow micro- and nanocrystals can not only increase the specific surface area of the materials but also benefit the understanding of the crystal facet-dependent catalytic activity. On the other hand, both the rational doping of heteroatoms and loading of co-catalysts can enhance the photocatalytic activity of semiconductor-based photocatalysts. However, up to now, there have been only a few reports on the synergetic effect of the two. In this work, BiVO4 hollow microplates (HMPs) and solid microplates (SMPs) were synthesized by a facile hydrothermal route, and B3+ ion-doped BiVO4 HMPs loaded with Co(OH)2 nanoparticles [Co(OH)2/B–BiVO4] were prepared through a one-step impregnation method. The as-prepared products were characterized in detail. The formation mechanism of BiVO4 HMPs was also proposed on the basis of time-dependent SEM observations and XRD analyses. Taking rhodamine B (RhB) as a kind of pollutant model, the photocatalytic activities of BiVO4 HMPs, BiVO4 SMPs, B3+ ion-doped BiVO4 HMPs, BiVO4 HMPs loaded with Co(OH)2 nanoparticles, and Co(OH)2/B–BiVO4 HMPs were systematically studied. The results show that {010}-dominant BiVO4 SMPs exhibited better photocatalytic activity for the degradation of RhB than {010} and {110}-dominant BiVO4 HMPs. In addition, the doping of B3+ ions and loading of Co(OH)2 nanoparticles could synergistically enhance the photocatalytic activity of BiVO4 HMPs. The present study not only provides reliable evidence for the crystal facet-dependent photocatalytic activity of BiVO4 but also develops a new strategy for enhancing its photocatalytic activity.
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DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
M. Thangarasu,P. Priyanka,K.L. Meghanathan,M. Parthibavarman,Sucheta Gaikwad,S. Vadivel,S. Rathinavel,D.R.P. Rajarathnam,Nouf H. Alotaibi,Saikh Mohammad
The issue of inadequate conductivity of electrons is consistently linked to the electrode material for pseudocapacitor , which hinders the complete utilization of the active material. In order to address this issue effectively, we have developed a composite material consisting of carbon nanotubes (CNTs) that are extremely conductive and wrapped around pseudocapacitive Co(OH) 2 nanobricks. The supercapacitor is created in our laboratory using a modified hydrothermal method (MHT) that allows for in situ growth. An electrochemical study confirms that the Co(OH) 2 @MWCNT electrode is extremely reactive, resulting in a maximum specific capacitance of 1911 Fg −1 (at 1 Ag −1 ). Furthermore, after 10,000 cycles of execution, it displays remarkable stability over the long term, with 96.5 % retention at a constant current density of 1 Ag −1 . In addition, the ASC has a significant energy density of 89.3 Whkg −1 at 1 Ag −1 . Furthermore, the device maintains an excellent energy density of 55.5 Whkg −1 while operating at a power density of 1015 Wkg −1 . In addition, the Co(OH) 2 @CNT//AC ASC has remarkable long-term cycling stability, with a just 4 % decrease in capacitance after 10,000 cycles. Furthermore, the device continues to maintain a commendable Coulombic efficiency of 83.5 %. These promising results indicate that these materials have the potential to be used in economical and reliable energy storage technologies .
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2024
·
IF 4.1
Xingnian Duan,Jianmei Cen,Xiaoyu Qiu,Xixiang Liu
The development of high-performance and cost-effective electrocatalysts for oxygen evolution reactions (OER) is key to renewable energy conversion and storage technologies. In this paper, a hierarchical Co(OH) 2 -MoO 3 nanosheets with petal-like architecture was prepared by a simple one-step hydrothermal method using ZIF-67/NF as a precursor, and it was used as a direct electrocatalyst for OER. Notably, this petal-like Co(OH) 2 -MoO 3 /NF layered nanosheets not only prevent the agglomeration of nanostructured material , but also facilitate the complete penetration and diffusion of electrolyte. In addition, due to the strong electronic interaction between Co(OH) 2 and MoO 3 in the Co(OH) 2 -MoO 3 /NF system, Co(OH) 2 -MoO 3 /NF exhibits excellent electrocatalytic OER performance. It has a low overpotential of 273 mV at 10 mA cm −2 and excellent stability. This study provides a simple and effective strategy for the rational design and structural evolution of MOF-derived materials to achieve inexpensive and effective electrocatalysis.
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RARE METALS
·
2025
·
IF 11
Ren Xiao-Qian,Chen Meng-Xin,Cao Xun,Dai Yu-Long,Yu Wen-Xiao,Liu Zhe,Wen Xin-Xin,Ma Guo-Xin,Guo Bing-Rong,Tan Sze-Xing,Liu Jia,Xu Ping,Gao Jia-Jian,Li Si-Wei
Metal oxohydroxides (MOOH) are widely accepted as the true active species for oxygen evolution reaction (OER). However, the MOOH converted from pre-catalysts usually exhibits better catalytic performance than those directly synthesized. The underlying structural reason for this phenomenon remains controversial. In this work, CoOOH and Co(OH) 2 with similar morphology are employed as model catalysts to investigate the origin of in-situ converted catalyst’s high activity, as Co(OH) 2 can be fully converted to CoOOH during OER. In-situ Raman, electron paramagnetic resonance, HR-TEM, and X-ray spectroscopic studies reveal that O vacancies in the CoOOH converted from Co(OH) 2 play a key role in its higher intrinsic activity towards OER than directly synthesized CoOOH. Furthermore, theoretical calculations and electrochemical methods indicate that O vacancies in CoOOH affect the interaction between Co–O bond, downshift the d-band center of Co, further weaken the adsorption of OH*, and finally facilitate the OER process over CoOOH. This work not only provides a deep understanding of pre-catalyst’s high OER activity by taking Co(OH) 2 as an example but also deliver insights into the activation process of other electrochemical oxidation reactions. Graphical
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