CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Changwei Bai,Gang Yang,Shirong Zhang,Shihuai Deng,Yanzong Zhang,Chao Chen,Jingsong He,Min Xu,Lulu Long
A novel electrocatalytic anode (ECA)/α-MnO 2 /peroxymonosulfate (PMS) synergistic system was developed and evaluated for the removal of combined tetracycline (TC) and hexavalent chromium (Cr(VI)) pollution from waste waters. The factors affecting the efficiency of the removal of the combined pollutants, such as the synthesis time of the electrode, the amounts of raw materials, the PMS dose, the voltage, the initial pH and the coexisting ions were investigated. The breakdown products of PMS in the ECA/α-MnO 2 /PMS system improved the conductivity of the solution and the electrical current promoted the conversion of the valence state of Mn ions, resulting in a synergistic effect between the ECA and PMS activation processes, which improved the efficiency of removal of TC. The cathode chamber was fully utilized to simultaneously reduce Cr(VI). Synergistic effects occur in the ECA/α-MnO 2 /PMS system in appropriate ranges of the voltage or PMS dose, although the efficiency of the removal of TC depends mainly on the electrical current in the system. Both hydroxyl (•OH) and sulfate (SO 4 •− ) radicals played important parts in the degradation of TC. The main degradation products of TC were identified and degradation pathways proposed. The synergistic effects between the ECA process and a Fenton-like process was studied, providing a new approach for the study of electro-Fenton technology and the removal of combinations of TC and Cr(VI) from waste waters.
研究领域:
环境科学
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污染控制
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电化学技术
✓ 已验证
DOI
高影响因子
ChemSusChem
·
2024
·
IF 7.5
Jie Yu,Manye Liu,Bo Wang,Chenxu Liang,Xuyi Wang,Kai Wang,Quanfang Lu
Graphical Flower-like α -MnO 2 nanospheres with assembled by dozens of nanosheets were fabricated using KMnO 4 as precursor via anode glow discharge electrolysis (AGDE), and then employed as a positive electrode material of supercapacitor to successfully light the light-emitting diode (LED). A novel green synthesis strategy–anode glow discharge electrolysis (AGDE) was employed for one-step preparation of α -MnO 2 in 2 g L −1 KMnO 4 solution, in which Pt needle and carbon rod were regarded as anode and cathode, respectively. The optimal preparation condition is 400 V for 60 min and the power consumption is below 45 W. The XRD, Raman spectra, XPS and EPR proved that α -MnO 2 with structural defects (oxygen vacancies) is obtained. SEM and TEM revealed that α -MnO 2 shows a flower-like nanospheres with a diameter of 165 nm, which is assembled by many nanosheets. A possible formation mechanism is that the MnO 2 is generated via the reduction of MnO 4 − by H⋅ and e aq − in plasma-liquid interface. Electrochemical test found that MnO 2 nanospheres exhibit a specific capacitance of 365 F g −1 at 1 A g −1 , and capacity retention of 79.8 % after 10,000 cycles at 5 A g −1 . The assembled asymmetric supercapacitor shows the maximum energy density of 23.1 Wh kg −1 at power density of 1.89 kW kg −1 . In brief, AGDE is a simple, facile and green technique for the synthesis of α-MnO 2 without adding extra chemicals, and prepared α -MnO 2 can be considered as an excellent candidate of electrode materials for supercapacitor.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Guangli Li,Yafeng Zhang,Yonghui Xia,Tianyu Wang,Yuan Jin
Excessive consumption of Sunset Yellow (SY) and Tartrazine (Tz) might cause adverse effects on human health. Hence, it is essential to develop a rapid and reliable technique for simultaneous determination of SY and Tz. Herein, an innovative voltammetric sensor was constructed for simultaneous determination of SY and Tz using multiwalled carbon nanotubes decorated dandelion-like α-MnO 2 microspheres (MnO 2 /MWCNTs). The physiochemical properties of MnO 2 /MWCNTs were studied by various microscopic, spectroscopic, and electrochemical techniques. Various parameters, including accumulation time, accumulation potential, loading volume, buffer pH, and scanning rate, were systematically explored in order to pursuit the higher peak current response. The MnO 2 /MWCNT effectively enlarged the electroactive surface area and expedited the electron transfer. As a result, the MnO 2 /MWCNT decorated glassy carbon electrode (GCE) displayed superior sensing performance for the electrooxidation of SY and Tz over a wide concentration range (0.06–10 μM), owing to the synergistic effect from dandelion-like α-MnO 2 microspheres and highly conductive MWCNTs. The detection limits were 0.005 and 0.01 μM for SY and Tz, respectively. In addition, the MnO 2 /MWCNT/GCE demonstrated strong anti-interfering capacity against potential interfering species, and highly reproducible electrode manufacture. The MnO 2 /MWCNT/GCE was successfully employed for the simultaneous and sensitive determination of SY and Tz in carbonate beverage with good recovery.
研究领域:
分析化学
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食品科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
IONICS
·
2024
·
IF 2.4
Gu Chengyang,Zhang Zhenzhong,zhang Xiaomin,Zhao Fangxia,Chen Haoyi,Tang Xingfeng
In order to determine the optimal crystalline form of manganese-based catalysts for zinc-air battery cathodes, in this paper nano-α-MnO 2 and amorphous manganese dioxide (AMO) materials were successfully synthesised by hydrothermal and liquid-phase co-precipitation methods, respectively. The results show that the spherical AMO material has larger specific surface area and more mesopores than the rod-like α-MnO 2 . Moreover, AMO has abundant structural defects and short-range ordered atomic arrangements that can enhance the ion diffusion kinetics and improve the catalytic performance of the materials. Through electrochemical tests, it is found that the AMO materials have better catalytic properties compared to α-MnO 2 . At a current of 10 mA/cm 2 , its discharge-specific capacity reached 575.2 mAh/g, which is 11.1% higher than that of 517.8 mAh/g for α-MnO 2 . And AMO have higher peak power density and smaller charge/discharge voltage gaps. In the long-cycle test, the initial round-trip efficiency of the electrode prepared of AMO is also better than that of α-MnO 2 . However, when the AMO electrodes are charged and discharged for a long time, part of the AMO will be converted to α-MnO 2 , which lead to a gradual decrease in the cycling stability of the AMO electrodes. Therefore, this paper concludes that AMO materials are superior to α-MnO 2 as catalysts for zinc-air batteries.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
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IF 6.551
Hao Zhou,Xiaoying Zhu,Baoliang Chen
A novel magnetic catalytic composite (MBM) was developed by compositing α-MnO 2 with a magnetic biochar containing Fe 3 O 4 . XRD and EDS confirmed the crystalline structure and the chemical composition of MBM, while the one-dimensional α-MnO 2 nanorods were observed on MBM by SEM. 4-chlorophenol as a typical toxic chlorinated organic compound was selected as the model pollutant. Even the MBM composite (MnO 2 content: 0.2 g/L) needed the same time (120 min) as the pure α-MnO 2 nanorods (0.2 g/L) to completely remove the 4-chlorophenol (10 mg/L) with overdosed peroxydisulfate (PDS), MBM indicated faster pollutant removal rate than the pure α-MnO 2 nanorods in the first 100 min. It is possible that the adsorption of 4-chlorophenol by biochar might shorten the migration pathway of the generated active species to the pollutants, resulting the boosted removal rate. MBM was stable in the neutral environment which was desirable for the efficient pollutant removal. Both the radical quenching tests and the EPR spectra identified the main active specie generated by activation of PDS through MBM was singlet oxygen possibly generated by recombination of superoxide ions from the metastable manganese intermediates at neutral pH. TOC data of the effluent ensured 63.5% of the pollutant molecules were completely mineralized after the degradation. The applied magnetic field could recover MBM easily for reuse. This work shed lights on the preparation of highly efficient and environmentally friendly catalytic composites for PDS activation in persistent pollutant removal.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysts
·
2023
·Vol. 13
·期 3
·588
·
IF 3.9
Haiou Zhang,Yixin Zhang,Huikang Song,Yan Cui,Yingying Xue,Cai-e Wu,Chao Pan,Jingxin Xu,Jian Qiu,Leilei Xu,Mindong Chen
As a toxic pollutant, carbon monoxide (CO) usually causes harmful effects on human health. Therefore, the thermally catalytic oxidation of CO has received extensive attention in recent years. The CuO-based catalysts have been widely investigated due to their availability. In this study, a series of transition metal oxides (Fe2O3, Co3O4and NiO) promoted CuO-based catalysts supported on the α-MnO2nanowire catalysts were prepared by the deposition precipitation method for catalytic CO oxidation reactions. The effects of the loaded transition metal type, the loading amount, and the calcination temperature on the catalytic performances were systematically investigated. Further catalyst characterization showed that the CuO/α-MnO2catalyst modified with 3 wt% Co3O4and calcined at 400 °C performed the highest CO catalytic activity (T90= 75 °C) among the investigated catalysts. It was supposed that the loading of the Co3O4dopant not only increased the content of oxygen vacancies in the catalyst but also increased the specific surface area and pore volume of the CuO/α-MnO2nanowire catalyst, which would further enhance the catalytic activity. The CuO/α-MnO2catalyst modified with 3 wt% NiO and calcined at 400 °C exhibited the highest surface adsorbed oxygen content and the best normalized reaction rate, but the specific surface area limited its activity. Therefore, the appropriate loading of the Co3O4modifier could greatly enhance the activity of CuO/α-MnO2. This research could provide a reference method for constructing efficient low-temperature CO oxidation catalysts.Keywords:transition metal oxides;CuO-based catalysts;Co3O4modification;α-MnO2nanowire;catalytic oxidation of CO
研究领域:
催化
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Dong Wang,Yumeng Wang,Xuefen Wang
In this work, a thorn ball-like three-dimensional (3D) heterostructured ZIF-67@α-MnO 2 catalyst consisting of ZIF-67 nanocages impaled by α-MnO 2 nanorods were robustly embedded in polyacrylonitrile nanofibers by electrospinning technique for highly efficient removal of low-molecular-weight pollutants (LMWPs, like dyes and antibiotics) from wastewater. Benefiting from abundant active sites and enhanced charge transfer abilities provided by ZIF-67@α-MnO 2 nanoparticles, the optimal ZIF-67@α-MnO 2 nanofibrous membranes (NFMs) showed a significant response towards acid fuchsin (AF) in terms of comparable adsorption capacity (2495 mg/g) and impressive catalytic activity (degradation degree of 99 % AF within 20 min). In addition, the resultant membranes possessed satisfactory versatile catalytic activity toward tetracycline (95.3 %), norfloxacin (98.4 %) and doxycycline hyclate (89.2 %). Besides, the resultant membranes had high permeability of 1302 L·m − 2 ·h − 1 driven by gravity and could efficiently treat 370.5 L·m − 2 AF (20 ppm), which was significantly higher than that of pure ZIF-67 NFMs (141.8 L·m − 2 ). The successful fabricating of such membrane with extraordinary adsorption and catalytic performance provided a promising approach for high-performance catalytic membranes.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Yanli He,Shuguang Shen,Ying Wang,Chenyuan Guo,Yaping Yuan,Yaru Fan,Lili Zhang,Yuyan Song
A simple and low-cost method for the synthesis of α -MnO 2 /C catalyst was proposed, in which KMnO 4 was reduced in-situ by cellulose in urea solution. The heterogeneous catalytic degradation of urea wastewater were carried out over α -MnO 2 /C. The effect of KMnO 4 -urea solution concentration on the structure and performance of the catalysts was investigated. The results indicate that δ -MnO 2 tends to curl and collapse into tunnel structure of α -MnO 2 as the concentration of KMnO 4 -urea solution increases, leading to α -MnO 2 is evenly distributed on carbon carrier. When the concentration of KMnO 4 -urea solution is appropriate, the catalyst has not only a large specific surface area but also high oxygen vacancy density, which is the key to be able to completely degrade the urea process wastewater. The reaction kinetics show that the catalytic hydrolysis of urea behaves as a pseudo-first-order reaction. A possible catalytic mechanism of urea hydrolysis over α -MnO 2 /C was proposed. In addition, the reusability experiments show that the α -MnO 2 /C catalyst has a good recycling ability.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Jingmin Yan,Zhengchen Li,Licheng Ma,Peiwei Han,Wenkai Zhao,Shufeng Ye
In this study, a highly efficient CuO/α-MnO 2 bimetallic catalyst was synthesized by hydrothermal and calcination methods and employed as a peroxydisulfate (PDS) activator for the degradation of thiocyanate (SCN − ) in aqueous phase. The effect of calcination temperature on the catalytic performance of CuO/α-MnO 2 and the mechanism of the CM350/PDS system were studied. Under optimal conditions, almost 100 % of SCN − (100 mg/L) was degraded within 90 min. XRD , XPS , Raman, and H 2 -TPR analyses revealed that the catalytic performance was enhanced in the CM350 catalyst due to the formation of M-O-Cu + -like structures (M = Mn 3+ , Mn 4+ , Cu 2+ ) through the combination of α-MnO 2 with CuO . The structures exhibit excellent redox ability and facilitate electron transfer between Cu and Mn elements, thereby improving the activation effect of PDS. Besides, the Cu 1.5 Mn 1.5 O 4 generated from the high calcination temperature was not conducive to the SCN − degradation reaction. Moreover, the mechanism study indicated that SO 4 ·- , ·OH, and the electron transfer pathway mainly accounted for the SCN − degradation. This study provides some guidance for the synthesis of PDS activation materials and the treatment of industrial wastewater by an advanced oxidation process .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Yingguang Zhang,Muyan Wu,Yifei Wang,Yu Ho Kwok,Wending Pan,Wai Szeto,Haibao Huang,Dennis Y.C. Leung
The particular role of fluorine (F) doping in the photocatalytic activity of nanocrystalline titanium dioxide (TiO 2 ) towards toluene degradation was systematically studied. TiO 2 nanosheet catalysts doped with different amounts of F − (denoted by F-TiO 2 ) were synthesized by hydrothermal method. For comparison, calcination was performed on the catalyst to remove F - . The photocatalytic oxidation (PCO) of toluene over F-TiO 2 was found to be much higher than those of TiO 2 and commercial P25 under the irradiation of vacuum ultraviolet (VUV) light, with a high toluene degradation efficiency of about 90 %. Moreover, the toluene degradation efficiency increased to 96 % with the addition of only 1 wt.% α-MnO 2 nanowires, and the residual ozone (O 3 ) in the system can be completely eliminated. In addition, four different substrates were explored for catalyst coating to facilitate the operation and minimize catalyst loading, which can provide a promising strategy for practical volatile organic compounds (VOCs) abatement in industrial applications.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Environmental Science-Nano
·
2023
·Vol. 10
·期 5
·1428-1440
·
IF 7.3
Xixi Chen,Yanjun Li,Wanyi Fu,Shuanghong Tian,Yulong Yang,Kai Yang,Xuanbo Xu,Xihui Zhang
The importance of nonradical Fenton-like catalysis in environmental fields has motivated research for effective singlet oxygen (1O2) production, but realizing the accurate design and regulation of active sites for manipulating oriented 1O2 generation is still highly challenging. In this study, α-, β-, and γ-MnO2 catalysts with different oxygen vacancy (OV) abundance were fabricated to activate H2O2 to generate 1O2 for the degradation of oxytetracycline (OTC). The OV-rich α-MnO2 had a high OTC removal efficiency (>93.5%) at the pH range from 4.0 to 11.0. Moreover, α-MnO2 exhibited great applicability for a real water matrix, and the total removal of various kinds of emerging contaminants from hospital wastewater reached up to 97.4%. The excellent performances of α-MnO2 were attributed to the rich contents of OVs that induced the oriented generation of 1O2. Theoretical density functional theory (DFT) calculations validated that the OV-rich α-MnO2 had the highest H2O2 adsorption ability (−1.39 eV) and the lowest energy barrier (0.41 eV) for the dissociation of *OH to form the *O intermediate, which promoted the oriented formation of 1O2. This work provides a strategy of manipulating the oriented generation of 1O2 towards water decontamination via regulating the abundance of oxygen vacancies in α-MnO2 nanocatalysts.
研究领域:
环境科学
·
催化化学
·
理论计算
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Jinmei Xu,Senqi Xu,Shangqing Tang,Luyao Wang,Kui Wan,Chuqiao Wang
The widespread use and release of 2,4,6-Trichlorophenol (TCP) poses a significant risk to water bodies and ecosystems. Designing efficient and stable catalysts for photocatalytic degradation of TCP remains a great challenge. In this paper, a Z-scheme α-MnO 2 /Bi 2 S 3 (Mn/Bi) composite enriched with oxygen (O Vs ) and sulfur (S Vs ) vacancies is designed for photocatalytic degradation of TCP. 60-Mn/Bi achieved 88 % degradation efficiency for 20 mg/L TCP solution. The reaction rate ( k ) of 60-Mn/Bi is 6.46 and 4.41 times higher than that of α-MnO 2 and Bi 2 S 3 , respectively. The catalyst exhibited high catalytic activity in a wide pH range and high resistance to anion. In addition, the cycling performance of 60-Mn/Bi is relatively stable, and the ion leaching rate is low. The Z-scheme mechanism is confirmed by characterization and DFT, which effectively retained the strong redox capacity. The abundant vacancy structure enhances the adsorption of TCP and promotes the migration of photogenerated carriers. In addition, the rod-shaped Bi 2 S 3 provides a carrier for α-MnO 2 nanoparticles, which effectively alleviates agglomeration and thus exposes more active sites. Three possible degradation pathways were explored by LC-MS and DFT. This study provides a facile method and guidance for the preparation of Z-scheme catalysts to improve photocatalytic degradation performance.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）