Processes
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2022
·Vol. 10
·期 12
·2562
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IF 3.352
Yuxi Gao,Baofang Jin,Xiaodong Wu,Zhenguo Li,Rui Ran,Duan Weng
Two Mn0.15Ce0.85O2−δmixed oxides were synthesized by a co-precipitation method using Mn(NO3)2and KMnO4as the manganese precursors, respectively. Structural analyses by X-ray powder diffraction and Raman spectroscopy reveal the formation of MnOx-CeO2solid solutions. The Mn0.15Ce0.85O2−δcatalyst prepared from the high-valent manganese precursor exhibits higher activity for the catalytic oxidation of NO. The advantage of KMnO4is related to the improved redox property of the catalyst as supported by H2temperature-programmed reduction (TPR) and O2temperature-programmed desorption (TPD). The Mn-Ce interactions create more Mn4+, Ce3+and oxygen vacancies on the KMnO4-synthesized mixed oxides based on the Raman and X-ray photoelectron spectra (XPS).Keywords:solid solutions;precursor;oxidation state;lattice defects;NO oxidation
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Journal of Environmental Chemical Engineering
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2023
·
IF 7.7
Qian Wang,Can He,Yue Shan,Zhongguo Zhang,Jiuyi Li
The aim of this study is to investigate the degradation efficiency and mechanism of atenolol (ATL) by catalytic ozonation with Al 2 O 3 supported manganese-cerium mixed oxides (Mn-Ce@Al 2 O 3 ), prepared by the impregnation-calcination method. The Mn-Ce@Al 2 O 3 with 0.2 wt% manganese and 0.2 wt% cerium exhibited superior catalytic performance, resulting in complete ATL degradation and 63% mineralization. Mn-Ce solid solution on the surface significantly increased the specific surface area (279.5 m 2 /g). High amount of Ce 3+ , Mn 3+ and high density of surface-active oxygen were contained on the surface of the catalyst, which facilitates the formation of oxygen vacancies and promotes the electron transfer in the catalyst. Combined with the low charge transfer resistance, surface protonated hydroxyl group, which was the active site of 0.2Mn-Ce@Al 2 O 3 , was more likely to adsorb ozone and decompose it into reactive oxygen species . O 2 · − and •OH were found to be the dominant active radicals for ATL degradation and mineralization that followed first-order kinetics. 17 intermediates were identified and 3 main degradation pathways were summarized, in order to provide reference for the complete mineralization of ATL.
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Journal of Physical Chemistry C
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2023
·
IF 3.7
Liang Jing,Qingmei Cen,Qi Pang,Jin Zhong Zhang
In this work, lead-free zero-dimensional (0D) all-inorganic perovskite Mn2+-doped Cs2InCl5·H2O microcrystals (MCs) with introduced Bi3+ ion were synthesized by supersaturation recrystallization at room temperature. The electronic bandgap of the MCs is tuned from ∼5.1 to ∼3.1 eV, and the electronic absorption is enhanced in the 200–400 nm region by Bi3+ incorporation. Upon excitation at 365 nm, the MCs with introduced Bi3+ exhibit strong red emission peaking at 640 nm, which is attributed to the Mn2+ transition (4T1g → 6A1g). Simultaneous Mn2+ and Bi3+ incorporation into Cs2InCl5·H2O shows 60 times enhancement of the 640 nm emission band compared to Mn2+ alone. This PL enhancement is attributed to the energy transfer (ET) from the [BiCl6]3– octahedron, which acts as a UV light absorber and exciton donor, to [MnCl6]4–. In addition, a yellow-light-emitting diode (LED) device based on the Cs2In0.45Bi0.55Cl5·H2O:17%Mn MCs was fabricated and evaluated, showing high color saturation at a drive current of 420 mA and good stability. This study demonstrates a new method for achieving efficient red emission by incorporating ns2 metal ions and Mn ions in 0D lead-free metal halides.
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Nano Today
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2022
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IF 18.962
Bei-Bei Yan,Chen-Cheng Xue,Meng-Huan Li,Liang Dong,Yang Zhao,Zhong Luo,Shu-Hong Yu
The drug resistance of hepatocellular carcinoma poses a great obstacle for chemotherapy as it severely undermines the clinical performance of common chemotherapeutics, and the implementation of nanotechnology-enabled combinational therapy offers new opportunities to circumvent this issue. Herein, an all-in-one hollow multi-component nanoformulation (aHNF) for hepatocellular carcinoma (HCC) treatment is reported, which could simultaneously load doxorubicin hydrochloride (Dox), chlorin e6 (Ce6) and manganic ions to realize Mn-amplified chemophototherapy. The loading strategy based on complexation effect and molecular selection establishes a simple yet effective platform for multi-component delivery via enhanced permeation and retention effect (EPR) and enables the sufficient release of photosensitizers to optimize the performance of photodynamic therapy (PDT). The co-delivery of Mn ions could elevate the cytotoxicity of both Dox and Ce6 via increasing the intracellular oxidative stress to damage cellular substructures and disrupt metabolic homeostasis . It also provides contrast for magnetic resonance imaging to guide the PDT treatment. This facile strategy allows to deliver multiple therapeutic modalities to hepatocellular carcinoma tissues, which then acts in synergy to overcome the treatment resistance of HCC and improves the antitumor activity .
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ENVIRONMENTAL ENGINEERING SCIENCE
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2022
·Vol. 39
·期 1
·56-63
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IF 2.172
Jie Zhang,Ben Dong,Jing Liu,Wuxu Yang,Sijie Ge,Shilong He
In this article, Mn doping on Ce-based γ-Al2O3 (i.e., Mn-Ce-γ-Al2O3) was synthesized and then employed as catalysts to study the removal of phenol from aqueous solutions through catalytic ozonation process. The results showed that the phenol removal was remarkably increased to 97.50% if Mn-Ce-γ-Al2O3 was adopted as the catalyst. In addition, the kinetic rate of the reaction was increased, approximately, about 1.49 times when using Ce-γ-Al2O3 catalyst with Mn doping. Moreover, X-ray diffraction, transmission electron microscopy, Brunner-Emmet-Teller measurements, and X-ray photoelectron spectroscopy techniques were used to comprehensively characterize the physicochemical properties of the synthesized Mn-Ce-γ-Al2O3 catalyst, including the phases, morphologies, textural properties, and dispersity of the surface active species. More uniform channel mesoporous structures were obtained after Mn doping on Ce-γ-Al2O3, which could enhance the gas-liquid mass transfer rate, surface hydroxyl groups, Ce3+/Ce4+ ratio, and the formation of Mn-Ce solid solution. In this study, the effects of Mn doping on Ce-based γ-Al2O3 on phenol degradation were investigated and the removal mechanisms were suggested for a better understanding of the improved removal efficiency.
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ENVIRONMENTAL POLLUTION
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2022
·
IF 9.988
Zhuozhi Ouyang,Fadan Lei,Endian Hu,Shuxing Li,Qian Yao,Xuetao Guo
Tetracycline (TC) and Mn(II) is a common antibiotic and metal ion respectively. Nevertheless, literatures involving in the effects of Mn(II) on TC transformation are still insufficient. In this study, the kinetic experiment, spectral analysis, complexation experiment and electrochemical analysis, theoretical calculation and products detection were carried out to probe into oxidation and photolysis of TC with Mn(II). Mn(II) greatly accelerated TC oxidation, preferably tending to complex with TC at O10 – O12 or O2 – O3 site. There were a TC-Mn(II)/TC-Mn(III) redox couple and electron transfer process. Conversely, Mn(II) inhibited photolysis of TC. The photolysis of excited TC could compete with energy dissipation reactions. The electron transfer and complexation reaction easily made excited TC energy transfer, thus slowing down photolysis process. During the TC transformation, the intensity of functional groups was significantly decreased. Simultaneously, the degradation pathways mainly included eight reactions. It is a very interesting and probably overlooked phenomenon, which identifies new transformation of TC with Mn(II). This study helps to further understand fate and environmental behavior of antibiotics and metal ion .
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高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 8
·2426-2437
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IF 6.177
Xinxin Zhang,Jiajun Dai,Jiageng Ding,Kok Bing Tan,Guowu Zhan,Jiale Huang,Qingbiao Li
Direct epoxidation of propylene (DEP) to propylene oxide (PO) with molecular oxygen is a very desirable reaction but remains a challenge due to the absence of efficient catalysts with high selectivity. The catalytic performance for direct epoxidation of propylene is well related to surface adsorbed electrophilic oxygen species. Herein, we prepared a series of Mn-doped La2CuO4 perovskites (LaMnxCu1−xO3) with adjustable valence electronic structure as selective catalysts to explore the impacts of catalyst intrinsic electronic structure evolution on the activation of molecular oxygen. Therein, LaMn0.5Cu0.5O3 performed the best with a PO selectivity of 74.2% at 150 °C. The characterization results and DFT calculations revealed that the excellent catalytic performance of LaMn0.5Cu0.5O3 might be ascribed to the change of molecular oxygen activation sites: from oxygen vacancy active sites on La2CuO4 to Cu active sites on LaMn0.5Cu0.5O3. Meanwhile, there was a synergistic interaction between manganese and copper affecting the electron density on Cu sites and ultimately modulating the activated states of surface adsorbed oxygen species. In addition, we employed crystal band theory to associate the oxygen vacancy density with the Cu valence state. This is important for people to understand the bulk electronic structure evolution rules caused by transition metal doping and to design catalysts efficiently for oxygen-based chemical reactions.
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Journal of Physical Chemistry C
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2022
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IF 4.177
Zhaoxia Yang,Wenming Tian,Fengke Sun,Shengye Jin,Dongjiang You
One-dimensional (1D) perovskites are ideal broadband-emitting phosphors for white-emitting diode applications. Doping Mn2+ in 1D perovskites provides a new idea to tune the materials’ light-emitting properties. Here, we report an excitation-power-dependent dual-band emission from both self-trapped excitons (STEs) and Mn dopants in individual 1D Mn-doped DMEDAPbBr4 single crystals. By changing the excitation intensity, we realize a broad and continuous color tuning range between blue and orange. The temperature-dependent photoluminescence (PL) and transient spectroscopy measurements demonstrate that the tunable emission color is enabled by the competitive transfers of excitons to the STE state and Mn2+ ions. The Mn-doped 1D perovskites exhibit a high photostability by showing a continuous switch between blue and orange emissions during an uninterrupted operation time of 7.5 h. The high stability and emission-color switchable properties make the Mn-doped 1D perovskites special optically tunable PL materials for potential light-emitting applications.
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International Journal of Environmental Research and Public Health
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2022
·Vol. 19
·期 15
·9437
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IF 4.614
Qianli Guo,Xianhu Qi,Jian Zhang,Bo Sun
Aqueous complexes of Mn(III) ion with ligands exist in various aquatic systems and many stages of water treatment works, while HSO3−is a common reductant in water treatment. This study discloses that their encounter results in a process that oxidizes organic contaminants rapidly. Pyrophosphate (PP, a nonredox active ligand) was used to prepare the Mn(III) solution. An approximate 71% removal of carbamazepine (CBZ) was achieved by the Mn(III)/HSO3−process at pH 7.0 within 20 s, while negligible CBZ was degraded by Mn(III) or HSO3−alone. The reactive species responsible for pollutant abatement in the Mn(III)/HSO3−process were SO4•−and HO•. The treatment efficiency of the Mn(III)/HSO3−process is highly related to the dosage of HSO3−because HSO3−acted as both the radical scavenger and precursor. The reaction of Mn(III) with HSO3−follows second-order reaction kinetics and the second-order rate constants ranged from 7.5 × 103to 17 M−1s−1under the reaction conditions of this study, suggesting that the Mn(III)/HSO3−process is an effective process for producing SO4•−. The pH and PP:Mn(III) ratio affect the reactivity of Mn(III) towards HSO3−. The water background constituents, such as Cl−and dissolved organic matter, induce considerable loss of the treatment efficiency in different ways.Keywords:Mn(III);bisulfite;advanced oxidation processes;sulfate radical;micropollutant abatement
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ENVIRONMENTAL RESEARCH
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2022
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IF 8.431
Yajie Guo,Xinyu Zhang,Dandan Zhang,Shunlin Li,Hui Wang,Yiyin Peng,Zhaoyong Bian
The present work demonstrates a simple one-step pyrolysis method for the synthesis of a catalytic sludge-based carbon (SBC) biochar containing Fe and Mn from dehydrated sludge with added KMnO 4 and Fe(II). The electrocatalytic degradation of triclosan (TCS) in water was evaluated using an Fe/Mn-SBC cathode to promote a heterogeneous Fenton-like reaction. The catalyst generated at 500 °C exhibited an abundant porous structure and a relatively high surface area, and produced an electrode with better conductivity and electron diffusion . The presence of metal oxides changed the surface structure defects of this biochar and enhanced its catalytic performance while increasing the electrochemically active surface area by 72.68 mF/cm 2 compared with plain SBC. TCS was degraded (91.3%) within 180 min by oxygen species generated in situ on an Fe/Mn-SBC cathode because the activation energy for oxygen reduction was lowered by 4.62 kJ/mol. The degradation of TCS followed pseudo first-order kinetics and was controlled by TCS diffusion and interfacial chemical reactions between adsorbed TCS and the electrode. Possible TCS degradation pathways were devised based on the main intermediates, and 1 O 2 was found to be more important than •OH radicals. Through toxicity test and prediction, the toxicity of degradation was gradually reduced. This study demonstrates a simple and ecofriendly method for the electrocatalytic degradation of organic pollutants.
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ACS Applied Materials & Interfaces
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2022
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IF 10.383
Yuming Xi,Yangcheng Lu
In this work, for the performance enhancement of iron hexacyanoferrate, an electrochemically active Mn-doped iron hexacyanoferrate cathode is fabricated via a bottom-up approach. It is found that the pre-treatment of interstitial water and appropriate Mn doping are two keys to achieving higher capacity and higher stability. The interstitial water has a trade-off effect between the alleviation of volume expansion upon Na+ (de)intercalation and the retardation of Na-ion diffusion. The moisture-tailored iron hexacyanoferrate with appropriate Mn doping exhibits a high initial Coulombic efficiency of 94.8%, enhanced capacity and rate performance, and excellent cycling stability. These results benefit from the fact that the extraction/insertion of Na ions from/into the lattice via a solid-solution mechanism correspond to both the slight volume expansion and fast sodium diffusion rate; otherwise, the removal of interstitial water and a higher Mn content might lead to poor cycling stability due to excessive volume expansion resulting from rhombohedral to cubic phase transformation. Finally, the less demand on the control of air humidity for the fabrication of electrodes and the potential for the full cell coupled with hard carbon are also demonstrated, which shows great potential for practical applications.
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Sustainable Chemistry and Pharmacy
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2022
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IF 5.464
Zhenwei Zhang,Xiaoshi Ma,Chuanjun Yue,Xuejiao Wei,Baoliang Liu,Xiaohui Chen
Hazardous waste alkaline batteries and waste fatty acids significantly threaten the environment. In this study, waste alkaline batteries were simply transferred to r-MnZn catalysts, which were then applied in the ketonization of fatty acids. The assessment results show that r-MnZn can efficiently convert n-octanoic acid to 8-pentadecanone. The conversion and yield are evaluated as 100% and 92.9%, respectively, which are much better than those of TiO 2 , ZrO 2 , CeO 2 and other metal oxides . The excellent catalytic efficiency is derived from the MnO 2 nanorods in r-MnZn materials which are characterized by XRD, TEM, and XPS. In addition, when using different kinds of fatty acids in ketonization, longer carbon chains require a higher activation energy, and the conversion of fatty acids was lower. Furthermore, the ketone products have a short carbon chain that induces side reactions, leading to a low yield. The above results indicate that r-MnZn is an efficient catalyst applied in the ketonization of fatty acids.
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