Analytical Methods
·
2016
·Vol. 8
·期 14
·2923-2928
·
IF 1.915
Xiaohua Li,Yun feng Bai,Feng Feng,Zhujun Zhang
Herein, we present a novel chemiluminescent (CL) sensor combined with an enzyme immobilization technique. We propose a versatile approach for the fabrication of CL sensors based on hydrophilic Co3O4@SiO2 mesoporous nanoparticles. The Co3O4@SiO2 mesoporous nanoparticles immobilized on the 96-well plates exhibited higher catalytic activity on the luminol–H2O2 CL reaction in an alkaline medium. Enzyme reactors were fabricated by incorporating functionalized mesoporous silica particles into calcium alginate fiber (CAF) to efficiently encapsulate the enzyme. The novel CL sensors combined with the enzyme reactors were reversible and reusable, which have been successfully exploited towards the high-throughput determination of glucose in human serum. The method was based on the generation of H2O2 from glucose in human serum by immobilized glucose oxidase (GOD). The linear range of the glucose concentration was 1.0 × 10−6 to 8.0 × 10−5 M and the detection limit was 1.2 × 10−7 M.
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高影响因子
ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Xiaoli Zhang,Jinbao Zhang,Kai Wang
Nanostructured Co3O4 doped with Zn2+, Ni2+, and both were directly grown on an ITO substrate by an easily available hydrothermal method. The doped Co3O4 showed a unique structural morphology evolution upon controlling the doping elements and the doping ratio of the cations. For the codoped samples, the novel rhombus-shaped Co3O4 nanosheets doped with Zn2+ and Ni2+ (concentration ratio of 1:2) exhibited the optimal electrocatalytic performance. The sample showed a current density of 165 mA cm–2 at 1.75 V, approximately 1.6 and 4 times higher than that of samples doped with Zn2+ and Ni2+ at a concentration ratio of 1:1 and 1:3. The unique architecture and its corresponding modified physical properties, such as high active-site density created by codoping, large structural porosity, and high roughness, are together responsible to its superior performance. For codoped Co3O4 nanostructures, Zn2+ facilitates the creation of Co cations in their high oxidation state as active centers, while Ni2+ contributed to the new active sites with lower activation energy. The synergistic effect of Zn2+ and Ni2+ doping can explain the improved physicochemical properties of codoped Co3O4 nanostructures.
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PubMed
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APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2015
·Vol. 119
·期 4
·1483-1490
·
IF 1.704
Wang Xiaoxia,Yu Jianhua,Dong Hongzhou,Yu Mingxun,Zhang Baoqin,Wang Wen,Dong Lifeng
In this work, metal oxide (MnO 2 , SnO 2 and Co 3 O 4 )–graphene composite materials were successfully prepared via different synthesis methods. Uniform metal oxide nanoparticles were well dispersed on graphene sheets, and transmission electron microscopy characterizations showed that the average sizes of MnO 2 , SnO 2 , and Co 3 O 4 particles were about 60, 5, and 10 nm, respectively. Reflection losses of graphene composites and pure graphene were systematically evaluated between 2 and 18 GHz, which revealed that all composites exhibited enhanced microwave absorption properties compared to pure graphene. The minimum reflection losses of MnO 2 -graphene, SnO 2 –graphene, and Co 3 O 4 –graphene composites with a thickness of 2.0 mm were −20.9, −15.28, and −7.3 dB at the frequency of 14.8, 15.94, and 9.6 GHz, respectively, whereas −4.5 dB for pure graphene. The enhanced absorption ability probably originated from the combined advantage of metal oxide particles and graphene, which proved beneficial to improve the impedance matching of permittivity and permeability. Besides, the intrinsic characteristics of MnO 2 , SnO 2 , and Co 3 O 4 nanoparticles, the interface between nanostructured metal oxides and graphene sheets, and the multi-dielectric relaxation processes are all influence factors to improve the properties of microwave absorption.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yibo Xu,Long Cao,Hele Hua,Rui Li,Yunfang Wang,Jianxin Liu,Yawen Wang,Caimei Fan
Electrocatalytic nitrate reduction, as an emerging sustainable process for ammonia production, has garnered significant attention in recent years. In this study, mixed metal oxides CoMoO 4 microspheres was obtained by adding Mo 5+ to the preparation process of Co 3 O 4 . The obtained CoMoO 4 can effectively convert NO 3 – to NH 3 in neutral electrolytes (with a yield of up to 1481.49 μg h −1 mg -1 cat and a Faraday efficiency (FE) of 91.17 %), much better than Co 3 O 4 (with a yield of 785.56 μg h −1 mg -1 cat and a FE of 81.3 %). Subsequent characterization showed that compared to Co 3 O 4 , owing to the introduction of Mo, CoMoO 4 could increase production as well as consumption of *H, and showed enhanced adsorption capacity for reactants and intermediates. More interestingly, multiple characterizations and theoretical computations confirm that after adsorption key *NO intermediates on each catalyst, the change in electron aggregation position led to a different subsequent reaction pathway from *NO→*NOH→*N of Co 3 O 4 to *NO→*NHO of CoMoO 4 , the latter exhibits a lower reaction energy barrier, better facilitating the hydrogenation of *NO and ultimately improving NH 3 yield and selectivity.
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2024
·
IF 4.2
Qi Ding,Hairong Li,Weining Liu,Dandan Huang,Xi Tan,Mingyang Zhao,Qionglin Cheng,Ming Yi,Yaqian Ren
Triethylamine (TEA) is easily volatilized and poses a huge health hazard. Therefore, the rapid detection of TEA is of great significance in environmental protection and industrial applications. In this paper, coral flower-like Fe-doped Co 3 O 4 was prepared using Co-MOF-74 as precursor. Compared with the pure Co 3 O 4 , Co 3 O 4 doped with 2 mol% Fe has better gas sensing performance of TEA. At an optimum operating temperature of 199 °C, the response to 100 ppm TEA is 21.2, five times higher than that of the pure Co 3 O 4 , with a short response recovery time (13 s/15 s). In addition, the gas sensor exhibits a certain selectivity and anti-humidity stability, with a minimum detection limit of 1 ppm at operating temperature. The higher Co 2+ /Co 3+ content in the sensor promotes the reaction of TEA with ionized oxygen, and amplifies the resistance change by adjusting the carrier concentration. Meanwhile, the introduction of Fe enriches the content of vacant oxygen and provides sufficient sites for the reaction and diffusion of TEA, further enhancing the sensing performance. In addition, Co 3 O 4 and Fe 2 O 3 combine to form p-n heterojunction , which helps to accelerate the gas adsorption-desorption process and improve the sensitive response speed. It creates a new design idea for the rapid detection of TEA gas by P-type metal-oxide semiconductors at relatively low operating temperatures.
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FERROELECTRICS
·
2024
·
IF 0.6
Muhammad Rafiq,Raza Ullah,Adeel Ahmed,Muhammad Usman,Bing Yu,You-Qing Shen,Hai-Lin Cong
Since traditional wastewater treatment techniques only partially remove antibiotics like metronidazole (MTZ), the rising use of these drugs causes their entry into wastewater and receiving surface waterways. A flexible method that may effectively degrade such organic pollutants is adsorption assisted photocatalytic degradation. Herein, an easy mixing-and-heating procedure was used to synthesize visible light-induced g-C3N4/Co3O4 heterojunction photocatalysts. The structural properties and morphology of as-prepared materials were measured using characterization techniques such as FTIR, FSEM, and XRD analysis. The as-prepared catalyst has demonstrated a remarkable adoption and photocatalytic performance in degrading MTZ. It was found that 0.2 weight percent of Co3O4 was the optimum amount for achieving the best photocatalytic efficiency. A key factor in boosting photo-generated carrier separation is the synergistic interaction between g-C3N4 and Co3O4. The kinetics study of MTZ adsorption and degradation as well as factors effecting such as pH (2-10) and catalyst dosage process were investigated. The functional treatment method attained 78% degradation of MTZ under the following general conditions: pH = 6, g-C3N4/Co3O4 = 0.04 g/L, and reaction time = 200 min and MTZ concentration = 20 mg/L. A possible mechanism for the photocatalytic degradation was introduced, wherein O2•− was found to be the leading radical, whereas h+ and HO• radicals contribute moderately to the degradation process. The research presents an appealing and environmentally friendly technique for the practical remediation of waste water carrying antibiotics.
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Inorganic Chemistry Frontiers
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2024
·
IF 6.1
Teng You,Shuang Xiao,Ping Huang,Chunyan Wang,Qiuxia Deng,Ping Jiang,Daiping He
Co3O4 has been explored extensively for glucose electrochemical detection, while it suffers from limited performance, due to the poor electrical conductivity originated from its semiconductor nature. Photethermal effect (PE) localized on the electrode surface has been illustrated as an attractive strategy in boosting water electrolysis, yet little insight was thrown on glucose electrochemical detection. In this paper, a one-stone-two-birds strategy to integrate PE and electrocatalytic activity of Co3O4 nanowires array supported on nickel foam (Co3O4 NWs/NF) was proposed for glucose electrochemical detection. Under near-infrared (NIR) light irradiation, the temperature of Co3O4 NWs/NF electrode was elevated, along with an enlarged electrochemical surface area (ECSA) and accelerated electron transfer process. PE assisted Co3O4 NWs/NF (PE- Co3O4 NWs/NF) shows high performance in glucose sensing, with a wide linear range from 1 μM to 0.73 mM, an excellent sensitivity of 26.17 mA mM-1 cm-2 and a low limit of detection of 0.56 μM. Moreover, PE-Co3O4 NWs/NF shows good feasibility and reliability for glucose determination in human serum samples. This work proposes a photothermal electrocatlytic dual functional system for glucose electrochemical sensing, and provides a novel approach in boosting Co3O4 catalytic activity in glucose detection.
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高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lihong Liu,Ming Yang,Bo Li,Duo zhang,Lihua Huo
In this paper, Au-modified Co 3 O 4 hollow nanospheres/graphene composites (Au-Co 3 O 4 /rGO) were synthesized for the first time through a novel “one-pot cooking” method at ambient temperature. The hollow nanospheres exhibited a particle size of approximately 10–15 nm, while the modified Au nanoparticles were about 4–5 nm in diameter. A high-efficiency and high response H 2 S gas sensor was constructed based on Au-Co 3 O 4 /rGO ternary composites. The effects of different Au modifying mass ratios on the H 2 S gas-sensitive performance of the composites were systematically investigated. At an operational temperature of 92 °C, the Au-Co 3 O 4 /rGO sensor, incorporating an Au loading mass ratio of 1.3 wt%, exhibited a response value of 175.4 for H 2 S at 100 ppm, a recovery time of 30 s, and a detection limit reaching as low as 10 ppb. This response was tripled compared to the undoped Co 3 O 4 /rGO sensor. At the same time, the H 2 S sensing mechanism by Au-Co 3 O 4 /rGO was discussed in detail.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Xiaocong Qin,Qi Xue,Changluo Su,Yuan Dang,Xiaoqin Sun,Yuanzhen Zhou
Catalytic oxidation is an efficient method for mitigating toluene emissions, but enhancing catalytic performance for toluene oxidation remains a challenge. To enhance the oxidation capacity of catalysts, appropriate morphology and composition adjustments are required. Herein, the porous CeO 2 -Co 3 O 4 hybrid nanosheets (CeO 2 -Co 3 O 4 HNSs) have been designed and prepared by the hydrothermal method . Compared with single composition CeO 2 and Co 3 O 4 , the CeO 2 -Co 3 O 4 HNSs exhibit superior performance, achieving a remarkable 90% toluene conversion at a reaction temperature of 215°C with a space velocity of 36,000 mL/(h·g). Their enhanced activity can be attributed to the unique morphology and multi-component synergistic effect. The introduction of Co can significantly increase the content of oxygen vacancy and optimize the electronic structure, which can enhance the formation of surface-active oxygen and accelerate the cycle of the Ce 3+ /Ce 4+ redox pair. This work establishes a promising avenue for treating volatile organic compounds in exhaust emissions.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2024
·
IF 5.8
Ze Gao,Renming Liu,Daming Yang,Hongji Xu,Yuqi Wang,Bowen Li,Ming Feng,Ting Wang,Gangyong Jin
The adsorption and activation of N 2 as well as the competitive hydrogen evolution reaction (HER) pose significant challenges to the electrocatalytic nitrogen reduction reaction (ENRR), which severely limits its industrial application. Therefore, exploring the ENRR electrocatalysts with high activity and selectivity is an extremely important task. In this work, the oxygen vacancy-rich Fe 2 O 3 /Co 3 O 4 heterostructures (referred to as Vo-X-Fe 2 O 3 /Co 3 O 4 ) were rationally designed by employing Co 3 O 4 as a template via a simple hydrothermal and subsequent calcination method, which acted as highly efficient ENRR electrocatalysts. The electrocatalytic activity of Vo-X-Fe 2 O 3 /Co 3 O 4 can be easily regulated by optimization of the Fe content and the introduction of oxygen vacancy (Vo). The results demonstrate that the optimized Vo-1.0-Fe 2 O 3 /Co 3 O 4 catalyst achieves a high NH 3 yield of 47.37 μg h −1 mg cat −1 and a Faradaic efficiency (FE) of 22.42 %. Moreover, the excellent stability and reproducibility are also demonstrated. The comprehensive characterizations reveal that the exceptional performance of Vo-1.0-Fe 2 O 3 /Co 3 O 4 can be attributed to the improved N 2 adsorption and activation, restricted competitive HER and promoted electron transfer kinetics induced by the synergistic introduction of Vo and Fe. This work emerged a new speculating orientation for rational design of ENRR catalysts.
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高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Peng-jie Zhu,Fang-yuan Su,Li-jing Xie,Xiao-Ming Li,Yong-feng Li,Cheng-Meng Chen
Research into environmentally friendly energy storage devices is a vital strategy to address the energy crisis and environmental pollution challenges. In this paper, oxygen-rich vacancy Co 3 O 4 /NiCo 2 O 4 heterojunction hollow nanocage electrodes were synthesized by a two-step hydrothermal and calcination method. Taking advantage of its unique structure, oxygen vacancies, and the synergistic effect of multi-element transition metal oxides, the electrode has good conductivity, high specific surface area, and abundant active sites. As a result, the Co 3 O 4 /NiCo 2 O 4 HHNCs electrode exhibits an ultra-high specific capacitance of 1788F g −1 at 1Ag -1 , and the assembled hybrid supercapacitor has an energy density of up to 43.9 Wh kg −1 , which is promising for applications in energy storage materials.
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高影响因子
Carbon Neutralization
·
2025
·Vol. 4
·期 4
·e70030
·
IF 12
Hailong Zhong,Chuanwang Zeng,Jiajun Lai,Guiyong Liu,luya Jin,Chao Liu,Xiaopeng Qi
Engineering vacancy defects is a critical approach to modulating the properties of catalytic materials. However, the development of highly efficient vacancy defect catalysts and the investigation of their roles and effects remain challenging. In this study, nitrogen-doped carbon-coated Co 3 O 4 porous nanomaterials were synthesized using ZIF-67 as a sacrificial template. Subsequently, through vacuum heat treatment, nitrogen-doped carbon-coated Co 3 O 4 porous nanomaterials with an appropriate amount of oxygen vacancies were finally obtained. This material exhibits excellent oxygen evolution reaction (OER) catalytic activity. At a current density of 10 mA cm −2 , the overpotential is only 293 mV, and it has good cyclic stability. The existence of oxygen vacancies has been confirmed by various characterization methods. Moreover, density functional theory (DFT) calculations show that oxygen vacancies can enhance the electrical conductivity of the material, optimize the binding energy of the intermediates in the OER, and significantly improve the catalytic activity. In this study, a method of designing high-performance OER electrocatalytic materials by regulating the oxygen vacancies in the nitrogen-doped carbon-coated Co 3 O 4 system is proposed, which opens up a new way for the development of efficient transition-metal-based electrocatalysts for water splitting. Summary Using ZIF-67 as a template, obtained uniformly dispersed nitrogen-doped carbon-coated cobalt tetraoxide has relatively abundant porosity. The introduction of oxygen vacancy defects significantly improves the electrical conductivity and specific surface area of the material in favor of electrocatalysis. DFT calculation shows that the introduction of oxygen vacancy can significantly improve the conductivity of the material, Co 3 O 4 system is conducive to the reaction of oxygen-containing intermediates, reduces the binding energy required in the reaction process, and improves the electrocatalytic activity of the material. The prepared Co 3 O 4 /NC-Ov-1 showed excellent OER catalytic performance (overpotential of 293 mV at 10 mA cm −2 ).
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