ACS Applied Nano Materials
·
2022
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IF 6.14
Le Zhang,Xin Zhou,Shaohua Chai,Jian Guan,Guijun Fan,Wuxinchen Yang,Guojun Ma,Ning Han,Yunfa Chen
There is a high demand to synthesize ozone decomposition catalysts especially in high-space-velocity and high-relative-humidity (RH) environments. Herein, two polymorphs of cobalt hydroxide, α- and β-Co(OH)2, are synthesized and applied for ozone elimination. β-Co(OH)2 shows ∼90% ozone decomposition efficiency under high space velocity (weight hourly space velocity (WHSV) = 1,200,000 mL g–1 h–1, 25 °C, 40 ppm), which is far higher than that of α-Co(OH)2 (∼5%). β-Co(OH)2 has high spin Co(II) in distorted octahedral coordination caused by the Jahn-Teller effect, leading to a higher crystal field splitting energy level and thus contributing to the easier electron transfer between the ozone and catalyst. Moreover, β-Co(OH)2 still shows high performance (∼87%) even in humid conditions (RH ∼50%, 25 °C, 40 ppm, WHSV = 600,000 mL g–1 h–1), which is attributable to its abundant surface non-hydrogen-bonded hydroxyls weakening water molecule adsorption, providing an idea to develop highly efficient catalysts for ozone decomposition in humid environments.
研究领域:
材料科学
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催化
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2019
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IF 4.561
Xiangrui Meng,Yijin Mi,Dongling Jia,Ning Guo,Yarui An,Yuqing Miao
Co hydroxide polymorphs (green α-Co(OH) 2 , red β-Co(OH) 2 and brown β-Co(OH) 3 ) formed at separate positions in a test-tube. Diffusion of hydrazine hydrate downward in agar gel facilitated the reaction between hydrazine and Co 2+ leading a dilatational wave of reactant concentration. The resulting periodic Liesegang bands of α-Co(OH) 2 were observed due to the diffusion hindrance of reactants. It can be deduced that the high concentration of Co 2+ causes formation of α-Co(OH) 2 while the low concentrations produce β-Co(OH) 2 . β-Co(OH) 2 is oxidized readily to form brown β-Co(OH) 3 at the upper area of agar gel with high alkali condition and O 2 distribution. This study is helpful to learn the formation of more than one product and prepare multiple materials in single chemical reaction system. In addition, the obtained α-Co(OH) 2 has been stabilized in the gel medium for at least 3 months. It may facilitate its application in many areas especially in electrochemical area since α-Co(OH) 2 typically exhibits higher conductivity and electrocatalysis than β-Co(OH) 2 while in the past its application often is limited by thermodynamically instability.
研究领域:
材料科学
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化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
IF 2.39
Hongtao Cui,Yunan Zhao,Wanzhong Ren,Minmin Wang,Yan Liu
In this work, α-Co(OH) 2 and β-Co(OH) 2 nanosheets were selectively synthesized through an epoxide precipitation reaction under mediation of fluoride ions. The protonation and ring opening reaction of propylene oxide promoted the hydrolysis [Co(H 2 O) 6 ] 2+ to form a mixed phase of α-Co(OH) 2 and Co 2 (OH) 3 Cl in the condition of no existence of fluoride ions. Due to the enhanced hydrolysis of [Co(H 2 O) 6 ] 2+ under function of fluoride ions, pure phases of α-Co(OH) 2 and β-Co(OH) 2 were formed respectively at different concentration of fluoride ions. The mild reaction condition of this route allows for large scale synthesis of cobalt hydroxide nanosheets, which is only limited by volume of the vessel used as reactor.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Xiaojin Yin,Wenhao Xi,Pan Wang,Tongchen Wu,Peide Liu,Bifen Gao,Yun Zheng,Bizhou Lin
It is crucial to develop highly active and durable bifunctional electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for rechargeable Zn-air batteries. Herein, we report a facile approach to synthesize 2D β-Co(OH) 2 nanosheets supported on 1D nitrogen-doped carbon nanotubes through a hydrothermal in-situ growth strategy of Co nanoparticles encapsulated N-doped carbon nanotubes and urea. The as-obtained Co(OH) 2 /NCNTs displays excellent bifunctional activity with a high half-wave potential of 0.85 V vs. RHE for ORR, a low overpotential of 312 mV at 10 mA cm −2 for OER, and a low potential gap of 0.69 V. Density function theory calculations show that the synergistic effort between doped carbon and β-Co(OH) 2 reduces the energy barriers of the rate determining steps for the former toward ORR and for the latter toward OER, contributing to the superior bifunctional catalytic performance. The assembled Co(OH) 2 /NCNTs- based battery performs a high specific capacity of 883 mAh g Zn -1 and remarkable cycle stability. This presented in-situ construction strategy provides an attractive rational design method for preparing carbon-based bifunctional electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2023
·
IF 6.2
Qi Sun,Zhijuan Li,Ningxin Liu,Yuting Zhou,Fuyan Zhang,Shuang Li,Peng Jin,Rui Xiang,Tao Le
There is an urgent need to develop an economical and convenient method for the ultrasensitive detection of patulin (PAT), a mycotoxin that can potentially harm human health when it is found in fruits and their derivatives. In this study, we have developed a novel fluorescent aptasensor that utilizes nitrogen-doped carbon dots (N-CDs) as the fluorescent donor and hexagonal β-Co(OH) 2 nanoplates as the fluorescent acceptor. N-CDs were synthesized through the hydrothermal method, resulting in spherical particles with a diameter of 7.6 nm. These nanoparticles exhibited excellent water solubility and displayed a vibrant blue emission at 448 nm when excited at 360 nm. Cobalt hydroxide nanoplates with a beta crystal structure [β-Co(OH) 2 ] were synthesized using a simple co-precipitation method, exhibiting hexagonal plate-like shapes with uniform lateral sizes of 4–5 μm. The fluorescence of N-CDs can be efficiently quenched by hexagonal β-Co(OH) 2 nanoplates through Förster resonance energy transfer mechanism. The maximum quenching-recovery capability can be achieved when the concentrations of N-CDs-Apt and β-Co(OH) 2 nanoplates are 150 nmol/L and 100 μg/mL, respectively. The pH of the TE buffer should be 8.0, and the incubation time should be 10 min at 25 °C. The developed fluorescent aptasensor displayed an excellent selectivity for PAT determination with a detection limit of 0.57 pg/mL in the linear range of 1.25 pg/mL-100 ng/mL. The rapid PAT determination in fruit juice samples was realized with good recoveries (96.9–105.8%). The developed fluorescent aptasensor based on the interaction between N-CDs and hexagonal β-Co(OH) 2 nanoplates can be a promising method for the rapid and ultrasensitive detection of PAT in agricultural products.
研究领域:
分析化学
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纳米技术
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食品安全
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）