CRYSTENGCOMM
·
2021
·Vol. 23
·期 43
·7602-7614
·
IF 3.545
Chao Feng,Gaoyan Xiong,Yaping Li,Qianqian Gao,Yuan Pan,Zhaoyang Fei,Yanpeng Li,Yukun Lu,Chenguang Liu,Yunqi Liu
Determining the effect of crystal facets on reaction performance is essential for designing an efficient propane oxidation catalyst. Herein, α-MnO2 nanowires with exposed (110), (211), (310) and (200) facets were proposed, and their crystal facet-dependent reactivity to propane oxidation was investigated. The resultant α-MnO2 nanowires with predominantly exposed (110) facets showed the maximum propane oxidation activity (T90 = 262.1 °C), oxidation rate, and turnover frequency (at 230 °C), and high stability during the oxidation of propane. In situ diffuse reflectance infrared Fourier transform spectroscopy revealed that the oxidation to form carboxylates is the decisive step; therefore, the production of reactive oxygen species is very important. The results from density of states computations revealed that the lowest electron energy was present in the (110) facet, which helps in the generation of reactive oxygen species and the regulation of the surface valence of Mn. The characterization and calculation results indicated that the (110) facets are conducive to forming oxygen vacancies, which allowed the activation and adsorption of O2 and propane, resulting in significantly enhanced propane oxidation activity. Apart from offering new insights about the structure–activity relationship of α-MnO2 with different facets exposed for short-chain volatile oxidation reactions, this study proposes a technique that can be used for improving other manganese-based catalyst oxidation systems.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2022
·Vol. 128
·期 7
·1-9
·
IF 2.983
Zhang Lei,Han Zhikun,Jia Yang,Han Yuzhen
Nitrogen oxides (NOx) could cause acid rain, photochemical smog, and even cause serious harm to human life and health and safety. Therefore, it was urgent to control and reduce NOx. In this paper, CeO 2 with a spherical structure was prepared by hydrothermal method, and the influence of different preparation conditions on the formation of CeO 2 was studied by orthogonal experiments. Then CeO 2 was used as the carrier, and a MnO 2 @CeO 2 core–shell catalyst with MnO 2 as the core and CeO 2 as the shell was developed. And it was successfully applied to SCO denitration. Through SEM, TEM and XRD characterization, the effects of different manganese-cerium ratios and core–shell morphology on the denitration performance were studied. The results showed that: (1) When the concentration of cerium chloride solution was 0.6 mol/L, urea was 30 g, glucose was 40 g, and the hydrothermal temperature is 200 ℃, the prepared CeO 2 catalyst had uniform particle size and high dispersibility. Its catalytic activity was better than that of catalysts prepared under other conditions, and the conversion rate of NO at 250 ℃ was up to 85%; (2) The denitration performance of the MnO 2 @CeO 2 composite3 catalyst was significantly better than that of the CeO 2 catalyst alone. At the same time, the MnO 2 @CeO 2 core–shell catalyst prepared with MnCl 2 ·4H 2 O as the manganese precursor had a better conversion rate of NO than that of the other two manganese precursor catalysts.
研究领域:
环境科学
·
催化材料
✓ 已验证
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2016
·
IF 5.886
Wenyue Gao,Zhongyuan Liu,Liming Qi,Jianping Lai,Shimeles Addisu Kitte,Guobao Xu
Glutathione (GSH) is a crucial antioxidant produced endogenously and plays key roles in biological systems. It is vitally important to design simple, selective, and sensitive methods to sense GSH and monitor changes of GSH concentration. In this work, the cathodic electrochemiluminescence (ECL) of lucigenin in the presence of MnO2 nanosheets at a glassy carbon electrode was utilized for GSH detection. GSH can reduce MnO2 nanosheets into Mn2+ which can obviously inhibit the ECL of lucigenin. The ECL inhibition efficiencies increase linearly with the concentrations of glutathione in the range of 10 to 2000 nM. The detection limit for GSH measurement is 3.7 nM. This proposed method is highly sensitive, selective, simple, fast, and cost-effective. Moreover, this approach can detect GSH in human serum samples with excellent recoveries, which indicates its promising application under physiological conditions.
研究领域:
分析化学
·
生物医学工程
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 2
·1-9
·
IF 5.479
Yu Jiani,Yang Weitao,Xing Shige,Wang Jun,Han Huanxing,Zhang Pengfei,Xiang Chenyang,Zhang Bingbo
A fluorometric and magnetic resonance (MR) dual-modal detection scheme is presented for determination of ascorbic acid (AA). It is based on the use of a blended Au/MnO 2 @BSA mixture that was prepared via a biomimetic strategy, using bovine serum albumin (BSA) as the template at physiological temperature. The MnO 2 @BSA fraction (one part of the composite) is not susceptible to MR but can be degraded to MR-active compounds upon a redox reaction with even ultralow concentrations of AA. In parallel, the blended Au/MnO 2 @BSA recovers its fluorescence because MnO 2 @BSA acts as a quencher of the fluorescence of circumjacent Au@BSA (the other part of the composite). Fluorescence typically is measured at excitation/emission wavelengths of 470/625 nm. Leveraging on this redox reaction between MnO 2 and AA, a dual-mode detection scheme for AA was developed. Both the fluorescence and the MR signal increase with the concentration of AA. The lowest limit for the detection of AA is 0.6 μM in the fluorometric mode and 0.4 μM in the MR mode. Analysis of AA-spiked serum samples showed that the recoveries obtained by either the fluorometric and MR mode can reach 94%. This is the first report of the use of blended nanoparticles with their inherent cross-validation regularity.
Schematic presentation of the biomimetic synthesis of blended Au/MnO 2 @BSA nanoprobes and fluorometric/MR cross-validation dual-modal detection of ascorbic acid.
研究领域:
分析化学
·
生物医学工程
·
纳米材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 19
·6879
·
IF 4.6
Tiantian Zhang,Jiacheng Xu,Yan Sun,Shiyu Fang,Zuliang Wu,Erhao Gao,Jiali Zhu,Wei Wang,Shuiliang Yao,Jing Li
Pt-based catalysts exhibit unique catalytic properties in many chemical reactions. In particular, metal–support interactions (MSI) greatly improve catalytic activity. However, the current MSI mechanism between platinum (Pt) and the support is not clear enough. In this paper, the interaction of 1 wt% Pt nanoparticles (NPs) onβ-MnO2in carbon monoxide (CO) oxidation was studied. The Pt onβ-MnO2inhibited CO oxidation below 210 °C but promoted it above 210 °C. A Pt/β-MnO2catalyst contains more Pt4+and less Pt2+. The results of operando DRIFTS-MS show that surface-terminal-type oxygen (M=O) plays an important role in CO oxidation. When the temperature was below 210 °C, Mn=O consumption on Pt/β-MnO2was less thanβ-MnO2due to Pt4+inhibition on CO oxidation. When the temperature was above 210 °C, Pt4+was reduced to Pt2+, and Mn=O consumption due to CO oxidation was greater thanβ-MnO2. The interaction of Pt andβ-MnO2is proposed.Keywords:metal–support interaction;CO oxidation;terminal-type oxygen;bridge-type oxygen;Pt;MnO2
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RUSSIAN JOURNAL OF GENERAL CHEMISTRY
·
2024
·Vol. 94
·期 3
·616-629
·
IF 0.9
Chen L.,Lian Q.,Li M.,Yu H.,Lv Y.,Guo M.,Zheng X.
Abstract Rod-shaped MnO 2 was synthesized by hydrothermal method. Ag@MnO 2 NRs were prepared with the Ag nanoparticles grown on the surface of rod-shaped MnO 2 by different reducing agents. The Ag@MnO 2 NRs were characterized by X-ray diffractometry, scanning and transmission electron microscopy, as well as X-ray photoelectron spectroscopy. The catalytic performance, catalytic mechanism and kinetic equation of the Ag@MnO 2 NRs were investigated. The as-prepared Ag@MnO 2 NRs were endowed with oxidase-like activity to catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue product without H 2 O 2 . Due to the inhibition of hydroquinone (HQ) on TMB oxidation, a simple, rapid, sensitive, and selective colorimetric sensor was set for the detection of HQ concentration in actual water. This method was established with an excellent linear range from 5–30 μM and a low detection limit of 1.7 μM. The colorimetric means could be availably used for the detection of HQ in river water samples and the RSD < 4.97%. The above results illustrated that the Ag@MnO 2 NRs had a great application prospect in environmental detection.
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
Materials Research Express
·
2019
·Vol. 6
·期 7
·075005
·
IF 1.449
Xiaoxiao Zhang,Xiaogang Su,Bin Zhang,Jun Wang
The MnO2@CNFs hierarchical structures have been successfully synthesized through a facile hydrothermal reduction method. By controlling the addition amount of KMnO4, the electromagnetic parameters and microwave absorption performance can be tuned effectively. When the mass ratio of CNFs and KMnO4 was 4:1, the obtained composites exhibited strong reflection loss of −42.77 dB at 4.32 GHz with an absorbent thickness of 4.5 mm. Meanwhile, the effective absorption region was 2.8 GHz (13.07–15.87 GHz) at a thin thickness of 1.5 mm. The superior electromagnetic attenuation performance of MnO2@CNFs is ascribed to the unique hierarchical structure. Further, the MnO2 nanoflakes vertically growing on CNFs modulate the complex dielectric parameters of MnO2@CNFs, leading to well-matched characteristic impedance. In addition, the interlaced conductive network is also beneficial for dissipating the incident EM waves through multiple scattering in the large surface area of MnO2. Prospectively, the synthetic strategy proposed in our work can be extended to the fabrication of other carbon-based microwave absorbing composites.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2025
·
IF 7.9
Xu Tian,Qi Wang,Jianzhong Yang,Rui Luo,Xiaolin Zhang,Shangyue Xue,Yuhang Shi,Wanning Hu,Zhe Liu
With the rapid development of electronic science and technology, the demand for portable and flexible energy supply strategies become urgent. Fiber supercapacitors attract extensive attention due to their lightweight, fast charge-discharge and excellent safety, which can be considered as potential energy storage devices to power electronic watches and the human motion monitoring system. MnO 2 shows high theoretical specific capacity, excellent physical/chemical stability and environmental friendliness, showing a broad application prospect as electrochemical active materials. This work proposes an optimal design strategy for MnO 2 -based fiber supercapacitors: β-MnO 2 and γ-MnO 2 are chosen as electrochemical active materials respectively, and the fiber electrode as well as fiber supercapacitors are fabricated via coaxial wet spinning. According to the results, γ-MnO 2 fiber supercapacitor presents the maximum C L of 0.86 μF/cm, E L of 9.65 10 −5 μWh/cm and P L of 0.33 μW/cm. After 10,000 charge/discharge cycles, the fiber supercapacitor can maintain the high level of consistency, demonstrating excellent long-term reliability. Furthermore, the electrochemical performance of the obtained fiber supercapacitors is almost unaffected in bending or knotting situations, indicating outstanding mechanical strength as well as flexibility. This work provides an effective basis for reliable design of fiber supercapacitors and promotes their application in flexible smart wearable field in the future.
研究领域:
材料科学
·
能源存储
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Muhammad Sultan Irshad,Xianbao Wang,Misbah Sehar Abbasi,Naila Arshad,Zihe Chen,Zhenzhen Guo,Li Yu,Jingwen Qian,Jun You,Tao Mei
Solar-driven steam generation is anticipated as one of the most promising and inventive technologies to address the primitive issues of water shortage. Although extensive attempts have been made to develop highly efficient solar steam generators, hindrances are faced to integrate all desired functions in a single evaporating system. Herein, we designed semiconductive in situ-polymerized MnO2 nanowires/chitosan (SPM-CH) hydrogels as flexible, built-in, vertically aligned, macropore-based water channels (∼0.5 μm pore size) for enhanced solar water generation (17.02 kg m–2 in 1 day). The nonradiative relaxation-dependent defect engineering of SPM-CH hydrogel promotes more lattice vibrations, and its polymeric network endorses the formation of enhanced intermediate water clusters for vapor generation. The self-floating and salt-resistant device possesses an excellent evaporation rate (1.78 kg m–2 h–1) during a single sunny day along with efficient solar energy conversion efficiency (90.6%) under 1 sun intensity, good solar absorption (94%), and good compressing flexibility (42% compressive strain). Moreover, COMSOL Multiphysics simulations of SPM-CH hydrogels under experimental conditions reveal its superior centralized heat accumulation within the top-interface matrix. The single-step execution for a freshwater supply purified from various contaminations including industrial wastewater and oil-emulsified water shows its potential as a reusable device toward real-life applications.
研究领域:
材料科学
·
能源技术
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Physics
·
2022
·
IF 11.021
Yue Liu,Zirui Jia,Jixi Zhou,Guanglei Wu
One-dimensional (1D) nanomaterials allow reflection of electromagnetic (EM) waves due to large anisotropy and aspect ratio. It is still a challenge to optimize the impedance matching characteristic for strong EM dissipation of 1D nanomaterials. Herein, we propose a strategy of incorporating two-dimensional (2D) layered double hydroxides (LDHs) sheets with 1D nanowires to reinforce interactions with EM waves. Wherein, 1D MnO 2 nanowires are used to support the LDH nanosheets , which facilitates the EM waves capture and impedance matching characteristics. Moreover, the heterogeneous interfaces and vacancies contributes to the polarization loss as well. As a consequence, the minimum reflection loss ( RL min ) of MnO 2 @ZnCoNi-LDHs demonstrates −56.3 dB at 2.4 mm and the broad effective absorption bandwidth ( f E ) reaches 4.56 GHz at 2.1 mm. This heterogeneous structure assembly strategy can be served as a reference for refining the absorption performance of 1D EM absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Yuelong Xu,Shasha Wang,Bin Ren,Junping Zhao,Lihui Zhang,Xiaoxi Dong,Zhenfa Liu
Carbon aerogels with excellent conductive characteristics and high specific capacitance have attracted more and more interests for next-generation energy storage applications. Three-dimensional interconnected Mn 2 O 3 /carbon aerogel supercapacitor electrodes are prepared by a novel doping method using MnO 2 coordinated by N, N-dimethylmethanamide (DMF). The coordinative MnO 2 (DMF/MnO 2 ) plays a key role in the sol-gel process of resorcinol and formaldehyde. The doped carbon aerogels exhibits a high specific surface area of 859 m 2 g −1 and a good pore-size distribution of 10–15 nm. All of the doped carbon aerogels exhibit higher specific capacitance than pure carbon aerogels, and the highest specific capacitance (170 F g −1 ), at current density of 1.0 A g −1 , is obtained in Mn–CA–5% when 5 mol% DMF/MnO 2 is added to the precursor solution. The specific capacitance is as high as 100 F g −1 , at current density of 10.0 A g −1 , and 97% of initial capacitance is retained over 1000 cycles at a current density of 5.0 A g −1 . The doped carbon aerogels exhibits a high coulombic efficiency (up to 99.8%) and a good rate capability. The corresponding result is due to the novel doping method of DMF/MnO 2 addition.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Shihang Zhang,Liying Zhang,Haipeng Ji
Mn 4+ -activated fluoride phosphors, exemplified by K 2 SiF 6 :Mn 4+ , exhibit exceptional narrow-band red emission but suffer from severe hydrolysis-driven degradation, significantly limiting their operational longevity. This study systematically investigates the stepwise degradation of K 2 SiF 6 :Mn 4+ upon water exposure, uncovering new insights into its hydrolytic behaviour. Upon immersion, the phosphor suspension undergoes a browning-clearing transition, attributed to the hydrolysis of [MnF 6 ] 2– which generates black suspended MnO 2 that temporarily darkens the solution before sedimentation. The degradation process involves two sequential stages: an initial rapid dissolution-dissociation of K 2 SiF 6 :Mn 4+ , accompanied by a sharp pH decrease, followed by relatively slower hydrolysis of [MnF 6 ] 2– and [SiF 6 ] 2– yielding crystalline MnO 2 and amorphous H 2 SiO 3 . Besides, upon reaching dissolution-ionization equilibrium, the released K + , [SiF 6 ] 2– , and [MnF 6 ] 2– ions would nucleate and precipitate, forming crystalline K 2 SiF 6 and K 2 SiF 6 :Mn 4+ particles with much smaller size compared to the original K 2 SiF 6 :Mn 4+ . Notably, this study reveals that the degradation of K 2 SiF 6 :Mn 4+ is significantly accelerated under both blue and UV light illumination, with UV light inducing faster degradation. These findings provide fundamental insights into the hydrolysis-driven degradation mechanism of Mn 4+ -activated fluoride phosphors, offering a scientific basis for developing strategies to enhance their stability and extend their service life.
研究领域:
材料科学
·
化学
✓ 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）