INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Zhiyuan Liu,Jingpeng Niu,Weimin Long,Bing Cui,Kun Song,Fan Dong,Dong Xu
Indoor formaldehyde from substandard furniture and decorative materials seriously endangers human health. How to remove effectively indoor formaldehyde with low concentration at room temperature is a challenging problem. Using a MnO2/AlOOH composite by the MnO2 modification as a catalyst provides an effective approach to solve this challenge. Here, a new type of MnO2/AlOOH composite catalyst with high ability to remove indoor low-concentration formaldehyde was prepared by redox reaction at room temperature. A MnO2/AlOOH composite with a homogeneous dispersion of MnO2 has high specific surface area and a large amount of surface hydroxyl (−OH) which plays a major role in the adsorption of formaldehyde. A partially crystalline structure was observed in the composite, which contains multivalent Mn ions and a large number of vacancy defects. The surface −OH of composite shows strong oxidation activity through the charge exchange of multivalent Mn ions and vacancy defects. The composite has a higher ability to remove indoor low-concentration formaldehyde compared to the birnessite MnO2 at room temperature. This study proposes a new idea for the improvement of catalytic performance in the structure and composition of the catalyst.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Yangyang Wang,Xue Wang,Bingcheng Ge,Jianxin Guo,Carlos Fernandez,Qiuming Peng
The Li–CO2 battery is a potential energy storage device that not only possesses a theoretical energy density as high as 1876 W h kg–1 but also alleviates the consumption of fossil resources by converting the greenhouse gas CO2 into electric energy. However, some technique bottlenecks, such as high overpotential, low recyclability, and low energy density, severely prohibit its application rhythm. Here, we prepare a binder-free MXene–MnO2 composite film using vacuum-assisted filtration and in situ reduction, which can be used as a freestanding cathode for Li–CO2 batteries. This MXene–MnO2 film electrode bestows good cycle stability (∼220 cycles), high specific capacity, and lower overpotential (∼0.89 V) in Li–CO2 batteries. Both experimental tests and first-principles calculations reveal that the enhanced electrochemical properties are associated with three aspects. First, the MXene–MnO2 film offers a high electrical conductivity and porous structure, which provide fast transport channels for electrons and ions. Then, the replacement of Mn by Ti increases the adsorption of Li ions, which facilitates the rapid decomposition of Li2CO3. Finally, the synergistic effect of MXene and MnO2 exposes a large number of active sites, which increases the capacity of Li–CO2 batteries. Therefore, this self-supporting strategy on the MXene composite paves a way to develop high-performance Li–CO2 batteries.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Shengnan Guan,Qifu Huang,Jianru Ma,Wenzhi Li,Ajibola T. Ogunbiyi,Zean Zhou,Kun Chen,Qi Zhang
The catalytic performance of MnO2(x)–CeO2 (x = Mn/Ce molar ratio) and the synergistic effect have been investigated in formaldehyde removal. The results showed that formaldehyde achieved 100% conversion at 60 °C for MnO2(1.5)–CeO2, with the gas hourly space velocity = 120 000 mL h–1 gcat–1. It was lower than the formaldehyde removal temperature of MnO2 (130 °C) and CeO2 (170 °C). The apparent activation energy for HCHO oxidation with MnO2(1.5)–CeO2 was 34.2 kJ mol–1. The partial mutual replacement of Mnx+ and Cex+ decreases the crystallite size due to the MnO2/CeO2 interaction. The X-ray photoelectron spectroscopy and the Raman analyses show that the Mn3+/Mn and Oads/Olatt ratios and the relative concentrations of oxygen vacancies for MnO2(1)–CeO2 and MnO2(1.5)–CeO2 were higher than those of the rest of the catalysts. Thus, the lattice oxygen (Olatt) from CeO2 readily transfers to the oxygen vacancy, achieving Olatt activation to surface-adsorbed oxygen (Oads).
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2016
·Vol. 4
·期 5
·1970-1979
·
IF 8.262
Juntao Liu,Xiao Ge,Xinxin Ye,Guozhong Wang,Haimin Zhang,Hongjian Zhou,Yunxia Zhang,Huijun Zhao
Novel three-dimensional (3D) graphene/δ-MnO2 aerogels were fabricated via self-assembly and reduction of graphene oxide, followed by in situ solution-phase deposition of ultrathin δ-MnO2 nanosheets. The resultant graphene/δ-MnO2 architectures showed an interconnected 3D network microstructure, in which a large number of ultrathin birnessite MnO2 nanosheets were homogenously deposited on the graphene framework. Due to their unique structural characteristics, the resulting 3D aerogels exhibited a fast adsorption kinetic rate and superior adsorption capacity toward heavy metal ions. The saturated adsorption capacities of graphene/δ-MnO2 aerogels were as large as 643.62 mg g−1 for Pb2+, 250.31 mg g−1 for Cd2+ and 228.46 mg g−1 for Cu2+ calculated by the Langmuir isotherm model, exceeding largely the corresponding pristine 3D graphene and δ-MnO2 nanosheets. It was noted that the heavy metal ions could not only adsorb on the surface of graphene/δ-MnO2, but also intercalate into the interlayer gaps of birnessite MnO2, which reveals the synergistic effect of the static electrical attraction, surface complexation and ion exchange between heavy metal ions and pre-intercalated K+, supported by the expansion of the basic crystal structure of layered MnO2 after adsorption. Furthermore, it is interesting that the regenerated aerogels after the initial HCl and subsequent KOH treatment still maintain their original shape and can be repeatedly used for more than eight cycles without obvious degradation of performance, which achieved the sustainability of the absorbents. More importantly, the hybrid aerogels can be easily separated and do not generate secondary contaminants. High removal efficiency, fast adsorption kinetics, excellent regeneration and reusability, and ease of separation operation make these hybrid aerogels ideal candidates for heavy metal ion decontamination in practical application.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
COMPOSITES COMMUNICATIONS
·
2019
·
IF 0
Fuhai Cui,Weidong Han,Yang Si,Wenkun Chen,Meng Zhang,Hak Yong Kim,Bin Ding
Catalytic oxidation is an efficient and cost-effective technology to eliminate HCHO, and MnO 2 shows excellent performance towards this kind of reactions. In this work, a birnessite type manganese dioxide nanoparticles modified silica-doped titanium dioxide (MnO 2 @SiO 2 –TiO 2 ) nanofibrous membranes were successfully synthesized by using an electrospinning technique and liquid phase synthesis . It is found that MnO 2 @SiO 2 –TiO 2 -4 nanofibrous membrane showed the best catalytic activity for HCHO removal. The as-fabricated nanofibrous membranes exhibited good and reversible catalytic oxidation activity towards formaldehyde, and more than 90% of the catalytic performance could remain after 5 testing cycles. The successfully constructed MnO 2 nanoparticles decorated soft SiO 2 –TiO 2 nanofibrous membranes, which can be a great promise for effectively solving the problem of environmental remediation.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
Nanoscale
·
2019
·Vol. 11
·期 40
·18845-18853
·
IF 6.97
Qi Wang,Chunyan Wang,Xiaodong Wang,Yuan Zhang,Yuehuan Wu,Chuan Dong,Shaomin Shuang
A multifunctional nanosensor of CPs@MnO2–AgNPs was constructed for sensitive and selective sensing of GSH and cancer theranostics in this work. The CPs@MnO2 nanocomposite was synthesized by capping MnO2 onto carbon nanoparticles through an in situ redox reaction under ultrasonication. AgNPs with fluorescence were obtained through a silver-mirror-like reaction using BSA as both a template and reductant and further anchored onto the surface of CPs@MnO2 through electrostatic interaction to construct the CPs@MnO2–AgNP nanocomposite. The fluorescence of AgNPs was effectively quenched by MnO2 through an inner filter effect and a static quenching effect and further recovered by GSH owing to the unique redox reaction between GSH and MnO2. Therefore, a novel fluorescent turn-on nanosensor was established for GSH sensing in vitro and in vivo. For GSH sensing, a satisfactory linear range of 0.8–80 μM with a detection limit of 0.55 μM was obtained under optimal conditions. Moreover, by integrating the GSH-responsive fluorescence imaging capacity, the photothermal activity of carbon nanoparticles and the anticancer effect of AgNPs, the CPs@MnO2–AgNP nanocomposite was successfully applied for cancer theranostics. The fluorescence recognition of cancer was achieved by overexpressing GSH in cancer, meanwhile the photothermal therapy from CPs and chemotherapy from AgNPs jointly produced an enhanced therapeutic effect. This redox-responsive nanocomposite of CPs@MnO2–AgNPs improves the MnO2 nanomaterial-based applications in GSH sensing and cancer theranostics.
研究领域:
生物医学工程
·
纳米医学
·
肿瘤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Xu Wu,Heqin Guo,Litao Jia,Yong Xiao,Bo Hou,Yongxiang Gao,Debao Li
δ-MnO 2 exhibits excellent activity for furfural oxidation to furoic acid under base-free conditions. However, its poor C H bond breaking capacity leads to lower conversion efficiency per unit mass catalyst than noble metal. Thus, a series of Ru-modified δ-MnO 2 (Ru x /δ-MnO 2 ) have been made to enhance its C H bond breaking ability. The result showed that the furfural conversion was greatly enhanced on Ru x /δ-MnO 2 due to the enhanced capability for breaking the C H bond. Especially for Ru0.25/δ-MnO 2 , whose conversion rate per unit mass was 18 times higher than δ-MnO 2 . The characterization results showed that the Ru species mainly existed as single atoms or clusters on Ru0.25/δ-MnO 2 and Ru0.5/δ-MnO 2 , while started to aggregate to RuO 2 nanoparticles on Ru1/δ-MnO 2 and Ru2/δ-MnO 2 . With the increase of Ru particles, the Ru's average oxidation state (AOS) decreased from +6 on Ru0.25/δ-MnO 2 to +4.74 on Ru2/δ-MnO 2. The Ru's TOF (intrinsic activity per Ru) was positively linearly related to the Ru's AOS. The electron-deficient Ru in Ru0.25/δ-MnO 2 can strongly adsorb the H atom of the C H of geminal diol intermediate and accelerate the breakage of its C H bond. As a result, Ru in the Ru0.25/δ-MnO 2 exhibited the highest TOF, which can even reach 29.85 mmol FF /mmol Ru /h.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2015
·
IF 6.217
Ke Wang,Shan Gao,Zhaolong Du,Anbao Yuan,Wei Lu,Liwei Chen
Practical supercapacitor devices require high areal capacitance and areal power density, and thus demand high utilization of active material and good rate performance under high areal mass loading. However, ion transport in high-mass-loading electrodes can be a challenge, which leads to deteriorate specific capacitance and rate performance. In this paper, a well-dispersed porous MnO 2 -carbon nanotube (CNT) composite was prepared for use as a supercapacitor electrode material . The small MnO 2 nanoparticles and porous CNT network facilitated fast electron/ion transfer kinetics in the electrode. With a mass loading as high as 6.4 mg cm −2 on the electrode, the MnO 2 -CNT composite exhibited an excellent areal capacitance of 1.0 F cm −2 at 0.2 A g −1 (1.28 mA cm −2 ), with a retention of 77% even at a high current density of 20 A g −1 (128 mA cm −2 ). The electrode exhibited a high power density of 45.2 kW kg −1 (0.29 W cm −2 ) while maintaining a reasonable energy density of 16.7 Wh kg −1 (106 μWh cm −2 ). No apparent fading was observed even after 3000 charge/discharge cycles at 1 A g −1 . This porous and evenly distributed MnO 2 -CNT composite has great potential for practical applications in supercapacitors .
研究领域:
材料科学
·
能源存储技术
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2025
·
IF 4.2
Yongle Zhang,Yingyi Tu,Yunying Huo,Guang Pan,Qiao Zhang,Zhiting Liu,Guangxing Yang,Feng Peng
The electrochemical catalytic oxidation of 5-hydroxymethylfurfural (HMF) to generate high-value products like 2,5-furandicarboxylic acid (FDCA) has become a prominent research interest. In this work, an economical and efficient transition metal ε-MnO2 catalyst was used to electrocatalyze the oxidation of HMF in acidic environments. The results revealed a highly efficient HMF conversion rate of 92.95% and a FDCA yield of 23.03% under the specific conditions of 60 °C, 0.5 M H2SO4 and 1.6 V (vs. RHE). Furthermore, the study outlined the oxidation pathway for HMF, which progresses through the following sequence: HMF → DFF → FFCA → FDCA. The apparent activation energies associated with each oxidation stage were found to be 25.52, 22.12 and 16.21 kJ mol−1, respectively. Moreover, the findings indicated a favorable relationship between the electrocatalytic oxidation activity of HMF and the average surface oxidation state of ε-MnO2.
研究领域:
化学
·
材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2025
·Vol. 236
·期 7
·1-16
·
IF 3
Jiang Yinying,Yu Jiang,Huang Zhi,Yu Jie,Deng Siwei,Zhu Weiwei,Zeng Zixin
Metformin (MET), recognized as the most extensively consumed pharmaceutical globally, exhibits minimally metabolized and is predominantly excreted unchanged. To remove MET from water, this study synthesized Fe 3 O 4 @MnO 2 (FM) catalysts, which could be easily recoverable using magnets. Notably, Fe 3 O 4 nanospheres, characterized by their superior crystallinity, significantly altered the morphology and structure of the externally wrapped MnO 2 . This modification resulted in an expanded surface area and an increased number of active sites. Furthermore, ultrasound (US) was employed to assist in peroxymonosulfate (PMS) activation, ensure effective dispersion of FM-5, and enhance the homogeneity of the reaction system. The synergistic application of US and FM-5 successfully activated PMS, achieving a remarkable MET degradation efficiency of 98.89% within 80 min, predominantly via a pathway governed by ·O 2 − and 1 O 2 . The FM-5/US/PMS system demonstrated robust adaptability under various environmental conditions. An analysis of the correlation mechanism revealed enhanced MET decomposition under alkaline conditions, thereby broadening the pH adaptation range of FM-5/US/PMS. Using density functional theory (DFT) calculations and HPLC–MS detection to propose degradation products, this study identified a product with comparatively lower toxicity. This work could offer a reference for further development of high performance and eco-friendly catalyst. Graphical
研究领域:
环境科学
·
材料科学
·
药学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Junhong Chen,Zhiwei Huang,Xinlong Liao,Shuangning Gan,Mingshuo Tian,Jiangwei Ni,Qiqi Zhou,Wen Chen,Juanjuan Gong,Jing Dong,Jia Chen,Huazhen Shen,Xiaomin Wu,Huawang Zhao,Guohua Jing
Tackling the urgent need for efficient catalytic abatement of harmful volatile organic compounds (VOCs), this study presents the controlled synthesis of hollow MnO 2 microcuboids with hierarchical structures for enhanced benzene oxidation catalysis. The hollow MnO 2 catalysts, obtained via a redox reaction between MnCO 3 precursors and KMnO 4 followed by selective acid etching, exhibit significantly higher surface area, oxygen defects, and Mn 3+ concentration compared to solid MnO 2 . Comprehensive characterization techniques reveal the structure–activity relationships governing the superior catalytic performance, which rivals that of a 1 % Pt/Al 2 O 3 reference catalyst. The unique hollow morphology, comprising thin shell walls built from interconnected nanorods, substantially enhances active site accessibility and lowers the activation energy barrier. A key feature of the hollow structure is its ability to concentrate reactants within the confined internal void through capillary action, a phenomenon that enriches reactant concentrations and further promotes catalytic activity. In-situ DRIFTS analyses provide mechanistic insights into surface species transformations during benzene oxidation. Notably, the hollow MnO 2 catalyst demonstrates impressive long-term stability and high activity in the presence of water vapor, highlighting its potential for practical industrial VOC abatement applications.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2020
·Vol. 26
·期 69
·16392-16401
·
IF 4.857
Chenxia Kang,Ju Fang,Likang Fu,Shuxian Li,Qiming Liu
Graphical Supercapacitive nanoarchitectures : A rationally designed 3D hierarchical carbon cloth/nitrogen-doped carbon nanowires/Ni@MnO 2 (CC/N-CNWs/Ni@MnO 2 ) nanocomposite was prepared by electrodeposition and used as a supercapacitor cathode exhibiting high surface area, outstanding electrical conductivity, and excellent performance in supercapacitors. A 3D hierarchical carbon cloth/nitrogen-doped carbon nanowires/Ni@MnO 2 (CC/N-CNWs/Ni@MnO 2 ) nanocomposite electrode was rationally designed and prepared by electrodeposition. The N-CNWs derived from polypyrrole (PPy) nanowires on the carbon cloth have an open framework structure, which greatly increases the contact area between the electrode and electrolyte and provides short diffusion paths. The incorporation of the Ni layer between the N-CNWs and MnO 2 is beneficial for significantly enhancing the electrical conductivity and boosting fast charge transfer as well as improving the charge-collection capacity. Thus, the as-prepared 3D hierarchical CC/N-CNWs/Ni@MnO 2 electrode exhibits a higher specific capacitance of 571.4 F g −1 compared with those of CC/N-CNWs@MnO 2 (311 F g −1 ), CC/Ni@MnO 2 (196.6 F g −1 ), and CC@MnO 2 (186.1 F g −1 ) at 1 A g −1 and remarkable rate capability (367.5 F g −1 at 10 A g −1 ). Moreover, asymmetric supercapacitors constructed with CC/N-CNWs/Ni@MnO 2 as cathode material and activated carbon as anode material deliver an impressive energy density of 36.4 W h kg −1 at a power density of 900 W kg −1 and a good cycling life (72.8 % capacitance retention after 3500 cycles). This study paves a low-cost and simple way to design a hierarchical nanocomposite electrode with large surface area and superior electrical conductivity, which has wide application prospects in high-performance supercapacitors.
研究领域:
材料科学
·
能源存储与转换
✓ 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）