ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·
IF 0
Wang Fei,Jin Yulong,Xue Yun,Yu Shuihang,Liu Na,Ma Qingxiang,Xu Jie,Xue Bing,Wei Xuejiao
It is desirable but challenging to develop highly-efficient catalysts for the direct synthesis of dimethyl carbonate (DMC) from methanol and CO 2 . The vacancy-mediated incorporation of heteroatom into surface reconstruction is an efficient method of defect engineering for enhancing the catalytic properties. In this work, manganese-doped cerium oxide porous nanoribbons (Mn/CeO 2 -BTC) were prepared derived from a Ce-BTC by a sacrificial template approach. It is found that the catalytic activity of Mn/CeO 2 -BTC catalysts can be readily controlled by varying the amount of Mn dopants and the as-synthesized 0.1-Mn/CeO 2 -BTC exhibited an outstanding activity for the synthesis of DMC from CO 2 and methanol, which reached a high DMC yield (6.53 mmol DMC /g cat. ) without any dehydrating agents. Based on characterization results, the enhanced performance may be attributed to the defective structures caused by Mn doping and the porous nanoribbons of the CeO 2 crystals, which provide more surface oxygen vacancies and acidic-basic sites, favoring adsorption and activation of CO 2 and methanol.
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DOI
PubMed
RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 5
·3135-3150
·
IF 1.674
Wang Cheng-zhi,Zhao Yong-gang,Zhang Cheng,Yan Xin,Cao Peng
Honeycomb cordierite-based Mn–Ce/Al 2 O 3 (Mn–Ce/Al 2 O 3 –C) and Fe–Mn–Ce/Al 2 O 3 (Fe–Mn–Ce/Al 2 O 3 –C) catalysts were prepared by an impregnation method and investigated in low-temperature selective catalytic reduction (SCR) of NO with NH 3 at 100 °C. The Fe–Mn–Ce/Al 2 O 3 –C catalyst exhibited not only higher catalytic activity, but also much better SO 2 and H 2 O resistance in the presence of 30 ppm SO 2 and/or 5 vol% H 2 O than Mn–Ce/Al 2 O 3 –C. After doping Fe, the NO conversion of Mn–Ce/Al 2 O 3 –C catalyst displayed an increasing trend from 79 to 84% in the absence of SO 2 and H 2 O at 100 °C under a gas hour space velocity of 1667 h −1 . The results of characterization indicated that addition of Fe was advantageous to increase BET surface area, pore volume and inhibit loss of surface Mn and Ce species. Additionally, it was helpful for generating higher concentration of Mn 4+ , more chemisorbed oxygen and more uniform dispersion of amorphous Mn and Ce in the surface of catalyst, which were beneficial to interact with reactants. Furthermore, in contrast to Mn–Ce/Al 2 O 3 –C, the SCR activity of Fe–Mn–Ce/Al 2 O 3 –C catalyst in the presence of H 2 O, SO 2 and H 2 O and SO 2 were 79, 75 and 64%, with the increase of 14, 18 and 19%, respectively. It is indicated that the addition of Fe could inhibit sulfate formation and thus enhance SO 2 resistance. XPS results reveal that the doping of Fe into the ceria lattice led to some Ce 4+ transferred into Ce 3+ in order to maintain the electrical neutrality, thereby facilitating the reduction of Ce 4+ → Ce 3+ and the formation of oxygen vacancies. NH 3 temperature-programmed desorption (TPD) results imply that the doping of Fe onto Mn–Ce/Al 2 O 3 –C can remarkably improve the distribution and concentration of acid sites. All the above factors contributed to the improvement of overall NH 3 SCR performance of the Fe–Mn–Ce/Al 2 O 3 –C catalyst compared with that of the Mn–Ce/Al 2 O 3 –C catalyst.
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DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Kang Li,Guang Li,Zhiwei Zhao,Xiaohong Ding,Na Li,Shuqi Ma,Yulong Zhang
Chemical looping-oxidative dehydrogenation (CL-ODH) is a promising technology for ethylene production from ethane. Exploring low cost and high activity redox catalysts to improve ethylene yield in the field of CL-ODH of ethane is necessary. In this study, a mesoporous Fe 0.4 Mn 0.6 O x redox catalyst with tunable lattice oxygen mobility was synthesized by a green solid-state grinding method, which used biomass based oxygenates as pore-forming and carbothermal reducing agent. The Fe 0.4 Mn 0.6 O x -0.3 xylitol redox catalyst prepared by this method possessed excellent catalytic performance, the ethane conversion rate and the ethylene selectivity reached 54.23% and 92.42%, respectively. It has been demonstrated that the highly active lattice oxygen in Fe 0.4 Mn 0.6 O x catalyst plays a key role in the ethane catalytic conversion. The high concentration of oxygen vacancies weakens metal–oxygen bonds, thereby promoting the migration of bulk-phase lattice oxygen to the redox catalyst surface to replenish the surface lattice oxygen. This work provides insights into the effects of biomass-based oxygenate species and doping levels on the lattice oxygen mobility of Fe 0.4 Mn 0.6 O x redox catalysts during the CL-ODH of ethane.
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Tianbao Xie,Rongxia Huang,Junhui Tan,Yan ning Luo,Hua-Tay Lin,Yejing Dai
CaBi 2 Nb 2 O 9 (CBN) is a bismuth layered ferroelectric material with extremely high Curie temperature and low dielectric loss, which has great application potential in ultra-high temperature field. However, because of its low piezoelectric coefficient, its practical application still faces great challenges. This study successfully prepared Ca 1-x Ce x Bi 2 Nb 1.98 (W 2/3 Mn 1/3 ) 0.02 O 9 ( x = 0–0.05) two-layer ferroelectric ceramics using direct-reaction sintering method. A pseudo tetragonal structure was successfully constructed near x = 0.02 using the substitution method of Ce 4+ at site A, and W 6+ and Mn 4+ at site B, which altered the crystal structure of CBN based ceramics. The properties of CBN-based piezoelectric ceramics have been significantly improved by this modification. It has a higher piezoelectric constant ( d 33 = 20.6 pC/N) and Curie temperature ( T c = 950 °C), while having a lower dielectric loss (tan δ = 0.031 at 500 °C). In addition, CaBi 2 Nb 2 O 9 based piezoelectric ceramics also show excellent thermal stability. After annealing at 900 °C for 2 h, the d 33 value remained high at 19.2 pC/N, retaining about 93.2% of its original value. Therefore, these findings indicate that Ca 1-x Ce x Bi 2 Nb 1.98 (W 2/3 Mn 1/3 ) 0.02 O 9 is a high-temperature piezoelectric material with great potential.
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Bingbing Liu,Yifei Zhang,Peidong Yang,Yanfang Huang,Yubin Xue,Hu Sun,Shuzhen Yang,Guihong Han
Zinc electrolyte crystallization sediment (ZECS) generated in the zinc hydrometallugy industry contains valuable metals of strontium (Sr), manganese (Mn), and zinc (Zn), which has economical value but poses potential detrimental to the environment. However, the extraction and recovery of Sr is extremely difficult due to the thermodynamically stable Ca and Sr sulfate cocrystallization structure in ZECS. The destruction of refractory sulfate cocrystallization structure is a prerequisite for Sr extraction, and the carbothermal reduction roasting method is demonstrated to be efficient for the phase reconstruction. In this study, a stepwise Sr, Mn, and Zn recovery process from ZECS via carbothermal reduction roasting-acid leaching-selective precipitation-multistage extraction was proposed. In the reduction roasting procedure, all the sulfates including CaSO 4 , SrSO 4 , and Ca 0.7 Sr 0.3 SO 4 are reduced to soluble sulfides. Meanwhile, most MnO 2 is converted to a low-valence Mn product (MnO) that is soluble in acid, and the reduced Zn (g) is volatilized which can be collected from the flue dust. In the acid leaching procedure, the leaching efficiencies of Sr, Ca, and Mn are as high as 97.34%, 97.44%, and 95.49% respectively, while 99.50% Si in the form of silica is enriched in the leaching residue. After that, high-purity Sr solution was obtained after selective precipitation for Mn removal and D2EHPA multistage extraction for Ca removal. 97.41% Mn in the leaching solution is precipitated by adjusting the pH value to 9.5 with NaOH solution. After four-stage extraction, 79.60% Sr and only 0.35% Ca are retained in the aqueous phase. The purified solution contains 2.88 g/L Sr, 0.052 g/L Ca, and 0.014 g/L Mn, which can be used to prepare industrial SrCO 3 product via the carbonation operation. Thermodynamic behavior and reduction roasting reconstruction mechanism of Ca and Sr sulfate cocrystallization structure in ZECS were discussed in this work. The distributions of main metal elements (Sr, Ca, Mn, and Zn) in ZECS during the carbothermal reduction roasting-acid leaching-selective precipitation-multistage extraction process were also systematically studied.
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DOI
高影响因子
Advanced Science
·
2020
·Vol. 7
·期 21
·2002199
·
IF 15.84
Qiuyu Shen,Xudong Zhao,Yongchang Liu,Youpeng Li,Jian Zhang,Ning Zhang,Chenghao Yang,Jun Chen
Iron/manganese-based layered transition metal oxides have risen to prominence as prospective cathodes for sodium-ion batteries (SIBs) owing to their abundant resources and high theoretical specific capacities, yet they still suffer from rapid capacity fading. Herein, a dual-strategy is developed to boost the Na-storage performance of the Fe/Mn-based layered oxide cathode by copper (Cu) doping and nanoengineering. The P2-Na 0.76 Cu 0.22 Fe 0.30 Mn 0.48 O 2 cathode material synthesized by electrospinning exhibits the pearl necklace-like hierarchical nanostructures assembled by nanograins with sizes of 50–150 nm. The synergistic effects of Cu doping and nanotechnology enable high Na + coefficients and low ionic migration energy barrier, as well as highly reversible structure evolution and Cu/Fe/Mn valence variation upon repeated sodium insertion/extraction; thus, the P2-Na 0.76 Cu 0.22 Fe 0.30 Mn 0.48 O 2 nano-necklaces yield fabulous rate capability (125.4 mA h g −1 at 0.1 C with 56.5 mA h g −1 at 20 C) and excellent cyclic stability (≈79% capacity retention after 300 cycles). Additionally, a promising energy density of 177.4 Wh kg −1 is demonstrated in a prototype soft-package Na-ion full battery constructed by the tailored nano-necklaces cathode and hard carbon anode. This work symbolizes a step forward in the development of Fe/Mn-based layered oxides as high-performance cathodes for SIBs.
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Chao Feng,Shanshan Qiao,Yuan Guo,Yuehong Xie,Li Zhang,Naeem Akram,Shiang Li,Jide Wang
The development of a highly efficient renewable heterogeneous catalysts for the synthesis of cyclic carbonates by the cyclic esterification of epoxides and carbon dioxide under relatively mild reaction conditions is of great significance in the territory of chemical fixation of carbon dioxide (CO 2 ). This work comprises on a functional catalytic material F-Mn-MOF-74 using an effective competitive coordination strategy, adenine (Ad) as alkali source and competitive ligand, introduced onto the synthetic Mn-MOF-74. An F-Mn-MOF-74 crystal having a spherical structure and being functionalized is obtained, and lone pair of electrons on the nitrogen atom in the adenine can compete with 2,5-hydroxyterephthalic acid for coordination. The alkalinity exhibited by adenine is beneficial to enhance the catalytic properties of the crystal in the cycloaddition reaction of epoxide with carbon dioxide. Further catalytic experiments showed that the functionalized F-Mn-MOF-74 crystal combined with tetrabutylammonium bromide in the lacking of solvent showed excellent catalytic activity in the cycloaddition reaction of styrene oxide and carbon dioxide. Under the optimal reaction conditions after screening (100 °C and 10 bar CO 2 pressure), the yield of cyclic carbonate was as high as 99 %. The excellent catalytic performance for other epoxides also confirmed that F-Mn-MOF-74 catalytic material is universal in its application. The catalytic performance of the catalyst was not significantly decreased after being recycled seven times, attributed to its excellent stability. The possible mechanism for the synergistic effect of Lewis acid-base properties of functionalized F-Mn-MOF-74 catalytic material with cocatalyst is also proposed.
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DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Xueyan Li,Lei Wang,Xin Zheng,Xiang Tu,Anhong Cai,Jing Deng
In this study, a UV-driven photocatalytic activation of peroxymonosulfate (PMS) system was constructed using bimetallic metal-organic frameworks to degrade pharmaceuticals and personal care products (PPCPs). Mn-MIL-53(Fe) was successfully synthesised by adjusting the doping ratio of Mn using solvothermal method. The removal of ibuprofen (IBP) by UV/Mn-MIL-53(Fe)/PMS process was as high as 79.7% in 30 min with a Mn doping ratio of 1.0 (molar ratio of Mn to Fe), and the reaction rate constant was 26.9% higher than undoped. Mn-MIL-53(Fe) had been systematically characterized in terms of its physical structure, microscopic morphology, surface functional groups and photoelectric properties. The mechanism investigation revealed that the cycling of Mn and Fe accelerated the rate of electron transfer in the system, which significantly increased the activation efficacy of PMS to generate more hydroxyl and sulfate radicals for IBP degradation. A total of 13 transformation products were detected during the degradation of IBP by the UV/Mn-MIL-53(Fe)/PMS process. Theoretical calculations were used to predict the sites on the IBP molecule that were vulnerable to attack, and four possible degradation pathways were deduced. The excellent stability and efficient catalytic properties of Mn-MIL-53(Fe) provided a promising solution to the problem of water treatment contaminated with PPCPs.
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DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Li Tang,Chunyu Wang,Sizhu Tian,Zhimin Zhang,Yong Yu,Daqian Song,Ziwei Zhang
Mn(II)-based electron spin resonance (ESR) spectroscopy was used for detecting butyrylcholinesterase (BChE) and organophosphorus pesticides (OPs). MnO2 nanosheets were synthesized with manganese chloride and hydrogen peroxide. With the catalysis of BChE, S-butyrylthiocholine iodide (BTCh) was hydrolyzed into thiocholine which has a reducing −SH group. In the presence of thiocholine, MnO2 nanosheets were broken down and Mn(IV) in MnO2 nanosheets was reduced into Mn(II). Mn2+ is a paramagnetic ion and gives a good ESR signal. In contrast, MnO2 nanosheets have no ESR signal and need not be separated from Mn2+. Mn2+ can be determined directly by ESR spectroscopy, and no further sensing probe is needed. ESR spectroscopy based on directly detecting Mn2+ is much simpler than those using other probes besides MnO2. The ESR signal of Mn2+ is proportional to the catalytic activity of BChE. OPs which inhibit the activity of BChE can also be detected by probing the ESR signal of Mn2+. Since there is no ESR signal of MnO2 nanosheets, the background signal in the absence of BChE was close to zero. The limit of detection (LOD) of BChE was as low as 0.042 U L–1. The standard curve for determining the OP paraoxon was established by measuring the inhibition of BChE by paraoxon, and the LOD of paraoxon was found to be 0.076 ng mL–1. The spiked Chinese cabbage extract samples were analyzed, and the experimental results indicated that the recoveries were from 96.5 to 102.8%. The planted Chinese cabbage was sprayed with the paraoxon solution, and the residue amount of paraoxon in the extract was estimated by the method. The result obtained by the present method was consistent with that obtained by HPLC, which proved the practicability of this new method.
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高影响因子
RSC Advances
·
2021
·Vol. 11
·期 3
·1524-1530
·
IF 3.361
Fan Bai,Lincheng Xu,Daode Wang,Li An,Zhanzhong Hao,Fan Li
Manganese oxide composites with mixed valence states were prepared through the hydrothermal method by compositing with Ti4O7 and calcining at different temperatures, and their ORR and OER catalytic performance were investigated. The prepared catalysts were characterized by XRD, SEM-EDS, HRTEM-EDS, and XPS methods to analyse their phase constitution, morphology feature, and surface composition. The major phase of manganese oxides was Mn3O4, which is a one-dimensional structure, and its growth was induced by Ti4O7. The ORR and OER catalytic activity can be enhanced due to the preferred orientation of manganese oxides. Electrochemical measurements, namely CV, LSV and EIS, were utilized for determining the ORR and OER catalytic activity, whereas CA and ADT were used for studying the durability and stability. A Li–O2 battery was assembled to test the electrochemical behavior and properties in practical application. MnOx/Ti4O7 calcined at 300 °C exhibited the best catalytic activity of 0.72 V vs. RHE half-wave potential for ORR and 0.67 V vs. RHE overpotential for OER. The proportion of Mn3+ was also highest in all the MnOx/Ti4O7 composites. The assembled Li–O2 battery shows high performance with a voltage gap of only 0.85 V. Therefore, it can be affirmed that the inducement of Ti4O7 could strengthen the preferred orientation in manganese oxide growth and Mn3+ in MnOx/Ti4O7 plays a vital role in catalyzing ORR and OER, with both improving the ORR and OER bifunctional catalytic performance of manganese oxides.
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DOI
高影响因子
IONICS
·
2018
·Vol. 25
·期 6
·2585-2594
·
IF 2.347
Meng Fanbo,Guo Huajun,Wang Zhixing,Wang Jiexi,Yan Guochun,Wu Xianwen,Li Xinhai,Zhou Lijiao
A series of layered Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 cathode materials, of which manganese source was electrolytic manganese dioxide, with different contents of SO 4 2− were successfully synthesized via ball-milling process and solid-state sintering method. The obtained materials were characterized by XRD, XPS, SEM-EDS, C-S, ICP, and HR-TEM. All the obtained materials presented well-ordered layered structure. When the content of SO 4 2− was below 1.30 wt%, the electrochemical properties and structural stabilities at low rate for the layered materials with SO 4 2− were not changed dramatically, while when the content of SO 4 2− increased to 5.85 wt%, the initial discharge capacities decreased dramatically from 248.24 to 209.23 mAh g −1 at 10 mA g −1 . And the pristine sample shows excellent cyclic property and rate capability. It delivered the discharge capacity of 175.25 mAh g −1 after 100 cycles with the highest capacity retention of 90.67% at 200 mA g −1 . Particularly, the treated Li-rich Mn-based materials with the highest amount of SO 4 2− exhibited the best cyclic stability and it delivers the highest capacity retention of 95.17% after 100 cycles at 200 mA g −1 . However, its discharge capacities were much lower than the pristine material. As a result, the addition of SO 4 2− could promote side reactions between electrode and electrolyte and deep-degree corrosion of electrode materials to affect the electrochemical properties and structural stabilities of the Li-rich Mn-based materials.
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Yuling Chen,Wei Huang,Chendi Wang,Xinyu Zhai,Ting Zhang,Yang Wang,Xiaoya Hu
Metalloporphyrinic frameworks have demonstrated to be an alternative candidate for natural enzymes due to their diverse structures and unique peroxidase-mimicking properties. In this study, a manganese–metalloporphyrin framework (PCN-222(Mn)) was synthesized as a biomimetic metal–organic framework (MOF). This catalyst exhibited highly intrinsic peroxidase-like activity with 3,3′,5,5′-tetramethylbenzidine as the chromogenic substrate. Additionally, a higher peroxidase-like activity was observed in a wider pH range (from 3.0 to 8.0), which is undoubtedly advantageous for PCN-222(Mn) to detect H2O2 under physiological and pathological environments. Based on the excellent peroxidase-mimicking activities of PCN-222(Mn), a novel hydrogen peroxide (H2O2) nonenzymic amperometric biosensor was constructed through electro-polymerizing a conductive and stable poly-glutamic acid (PGA) film on the surface of a PCN-222(Mn)-modified electrode (PGA/PCN-222(Mn)/GCE). Resulting from the synergistic activity of PCN-222(Mn) and PGA film, a sensitive, selective, and reliable method was established for H2O2 detection with a linear range of 5 × 10–7 to 1.01 × 10–3 mol/L and detection limit of 3.1 × 10–8 mol/L. In addition, PGA/PCN-222(Mn) has a long-term stability and can be used over 90 cycles without any decrease in analytical performance. These outstanding performances of the developed approach in sensitive and selective determination of H2O2 from human serum provides effective proof for its potential application in monitoring low-abundance H2O2 from complicated biological samples. This research not only expands the electrochemical applications of metalloporphyrin frameworks but also demonstrates a promising strategy for increasing the conductivity and stability of MOF-based electrode materials.
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高影响因子
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