CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
JiaYu Chen,Peng Fu,Daofei Lv,Yang Chen,Meiling Fan,Junliang Wu,Amogh Meshram,Bin Mu,Xiang Li,Qibin Xia
A high-performance denitration catalyst based on Mn-Ce mixed-oxide derived from a specific Mn/Ce precursorwas fabricated by solvothermal method. It exhibited outstanding low-temperature activity, which achieved above 90% NO x conversion in the temperature of 150–310 °C. Remarkably, Mn-Ce mixed-oxide demonstrated a much better SO 2 tolerance, in which the NO x conversion increased from 92.6% to 97.8% at 150 °C after introducing 200 ppm SO 2 . The synthesized Mn-Ce mixed-oxide has a porous structure with abundant chemisorbed oxygen spices and exposed active sites. In addition, the increased acidity and redox capacity enhanced the catalytic activity after introducing SO 2 . Meanwhile, the injection of SO 2 separates NH 3 adsorption sites from oxidation agents, inhibiting the unwanted oxidization of ammonia to nitrogen oxides. Furthermore, the reaction pathway on Mn-Ce mixed-oxide proved to be the L-H mechanism based on in situ DRIFTS. Thus, the synthesized Mn-Ce mixed oxide demonstrated an excellent denitration performance and the especially high SO 2 tolerance, showing great potential for low-temperature NH 3 -SCR.
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Catalysts
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2020
·Vol. 10
·期 11
·1329
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IF 3.52
Shijie Hao,Yandi Cai,Chuanzhi Sun,Jingfang Sun,Changjin Tang,Lin Dong
Monolithic Mn-Fe-Ce-Al-O catalyst with honeycomb cordierite ceramic as a carrier was reported for the first time for low temperature deNOxapplication. In the reaction of selective catalytic reduction (SCR) of NO with NH3, a NO conversion of above 80% at 100 °C was obtained. Notably, the catalyst also showed excellent resistance against SO2and H2O. About 60% NO conversion was maintained after successive operation in the mixed stream of SO2and H2O for 168 h. The Brunner−Emmet−Teller (BET) measurement, SEM, EDS, thermogravimetric analysis (TG), FT-IR, and XPS results of the used catalysts indicated that certain amounts of ammonium sulfate was formed on the surface of the catalyst. XPS results revealed that partial of Fe2+was oxidized to Fe3+during the reaction process, and Fe2+species have strong redox ability, which can explain the decrease in activity after reaction. In addition, SO2and H2O induced a transformation of Ce from Ce4+to Ce3+on the surface of the catalyst, which increased the amount of chemisorbed oxygen. Owing to these factors, the addition of Ce and Fe species contributes to excellent resistance of the catalyst to SO2and H2O.Keywords:honeycomb catalyst;Mn-Fe-Ce-Al-O;low temperature denitration;water and sulfur resistance
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CATALYSIS LETTERS
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2020
·Vol. 151
·期 4
·966-979
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IF 2.482
Liu Qinglong,Yang Jingchao,Luo Mingsheng,Yang Zhi,Zhao Qiuna
Abstract A series of Mn–Ti oxide catalysts were synthesized by the sol–gel method and the effects of different synthesis conditions were investigated in sequence. The microstructures and properties of the catalysts were characterized by using N 2 adsorption–desorption, XRD, SEM, H 2 -TPR, NH 3 -TPD, Raman and XPS. The catalytic performance over Mn–Ti oxide catalysts prepared under different synthesis conditions for the low-temperature SCR of NO with NH 3 were also comparatively evaluated. The results reveal that the calcination temperature and metal source play a significant role in the characteristics and the SCR activities of the catalysts. A relatively low calcination temperature is beneficial to low-temperature SCR activity. Manganese nitrate or manganese acetate as the Mn source combining with tetrabutyl titanate as Ti source can achieve high SCR activities. The excellent low-temperature NH 3 -SCR activity can be ascribed to the appropriate textural properties, amorphous Mn-oxides with equal ratio of Mn 3+ /Mn 4+ , good low-temperature reducibility and abundant surface B-acid sites. Graphic Abstract
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2021
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IF 4.464
Yinghui Han,Junxiu Zhou,Lidong Wang,Lei Xing,Zhiwen Xue,Yunpeng Jiao,Yiheng Pang
The metal-organic frameworks (MOF) is a promising electrode material for supercapacitor , but the traditional monometallic metal-organic frameworks are limited by poor conductivity and structural stability. In this work, a novel manganese (Mn) and nickel (Ni) bimetallic metal-organic frameworks anchored on multi-walled carbon nanotubes (Mn/Ni-MOF@MWCNTs) were fabricated via a one-step solvothermal method . The morphologies, micro-structures and electrochemical properties of Mn/Ni-MOF@MWCNTs with different mass ratios of Mn and Ni were compared. The results indicated that multi-walled carbon nanotubes (MWCNTs) provides numerous active anchoring sites which is introduced into the architecture of the optimal Mn/Ni-MOF; these sites are responsible for enhancing the electrons transfer and structural integrity, with the small contact resistance and charge transfer resistance. As a result, a specific capacitance of 793.6 F g −1 at 1 A g −1 in 1 M LiOH aqueous solution was achieved, and the capacitance retention was retained at 74.92% after 1000 cycles at 1 A g −1 . The crystal structures and valence band information of the anchored Mn/Ni-MOF were obtained by DFT calculation. Besides, Mn/Ni-MOF@MWCNTs//Mn/Ni-MOF@MWCNTs symmetry supercapacitor showed an excellent energy density of 33.2 Wh kg −1 at a power density of 1198 W kg −1 and stabilizing capacity retention of 78.3% over 2000 cycles. These results provide a promising strategy for high-performance electrochemical energy storage .
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MATERIALS & DESIGN
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2017
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IF 4.364
Xiu Liu,Lei Huang,Dengsong Zhang,Tingting Yan,Jianping Zhang,Liyi Shi
This work reports the synthesis of highly dispersed Mn-Co/RGO via a novel light driven approach having attributes of being green, facile and controllable, for the catalytic degradation of methylene blue (MB) in the presence of H 2 O 2 . The prepared catalysts were characterized by TEM, EDS , IR, XRD and XPS techniques. A synergy between RGO and Mn-Co species existed where the former helped in adsorption of MB and stabilization and dispersion of Mn and Co on the surface while the latter improved H 2 O 2 utilization by generating HO , which enhanced the decomposition of MB. It was found that O 2 •− and O 2 •− /HO • were the main radicals in post Mn/RGO and Mn-Co/RGO treatment, respectively. Both O 2 •− and HO • oxidized MB with a faster rate by the former, but its side reaction can hinder effective utilization of H 2 O 2 while the reverse was true for the latter. A 50 mg/L MB was completely decomposed within 15 min using 10 mg of Mn-Co/RGO. Thus the synergistic effect of RGO by adsorption MB and Co species avoiding the side reaction led to enhanced rate of MB decomposition.
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Analytical Methods
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2020
·Vol. 12
·期 27
·3513-3522
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IF 2.596
Zhenping Liu,Jingzhou Hou,Qiang He,Xiaogang Luo,Danqun Huo,Changjun Hou
In this work, a new application of Mn-doped ZnS quantum dots (Mn-ZnS QDs) was developed to screen chloramphenicol (CAP) and tetracycline (TC) residues simply and rapidly. Mn-ZnS QDs synthesized by a hydration method and modified by L-cysteine for better stability emit phosphorescence at 583 nm with the excitation wavelength at 289 nm. Based on the overlap of the Mn-ZnS QDs excitation spectra and CAP or TCs ultraviolet spectra, the excited light of the Mn-ZnS QDs was partially absorbed by CAP or TCs owing to the inner-filter effect (IFE), leading to a decrease in the phosphorescence intensity. The phosphorescence intensities of the samples prepared by mixing different TCs and CAP were in good agreement with the expected results from adding a single antibiotic sample. Therefore, the total molar concentrations of CAP and TCs could be screened based on the linear equation of a single standard substance. Represented by tetracycline (TC), as a member of the tetracycline family, under optimized conditions, showed a good linear relational concentration range over 4 orders of magnitude from 50 to 1.5 × 105 nM with a limit of detection (LOD; S/N ratio = 3) down to 8.6 nM. The phosphorescent sensor was also used to detect total TCs in actual samples successfully. The evaluations of the recovery rate and selectivity were good. These results demonstrated that the presented phosphorescent sensor can be a simple and rapid screening platform for CAP and TCs.
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PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
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IF 7.632
Heng Ban,Youdi Zhang,Shuaibo Chen,Youwei Cheng,Teng Pan,Lijun Wang,Xi Li
In this contribution, readily available 5-methyl furfural (MF) derived from biomass was used as an excellent substitute of the chemically unstable 5-hydroxymethylfurfural (HMF) for preparing the commercial precursor 2,5-furandicarboxylic acid (FDCA). MF was catalytically oxidized by air into FDCA in acetic acid over homogeneous Co/Mn/Br catalysts at 130–170 °C. It was found that both the substitute reactivity and the ring chemical stability have a remarkable impact on the yield of aromatic dicarboxylic acids. The effects of reaction temperature, pressure, catalyst composition and concentration, water concentration in the solvent, and substrate/solvent mass ratio on both the main reaction and the side reaction were investigated systematically and thoroughly using HPLC and an online tail gas monitoring system. Under optimized conditions, the oxidation of MF gave 100% conversion of MF and 75.8% yield of FDCA with 99.6% purity. It was also proven that the addition of 200 ppm cerium could work well at low temperatures (130–140 °C) for enhancing FDCA selectivity via suppressing the side reactions.
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JOURNAL OF POWER SOURCES
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2020
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IF 8.247
Asim Arshad,Sining Yun,Yiming Si,Feng Han,Yongwei Zhang,Yangliang Zhang,Ziqi Wang,Chen Wang
We propose a facile strategy to synthesize highly electrocatalytic active nanohybrids by the integration of aloe vera-peel derived porous carbon into manganese-based and cobalt/manganese-based oxides. These nanohybrids exhibit unique three-dimensional porous network structures and possess high surface areas, providing numerous catalytic sites and multiple rapid electron transfer channels. In this work, the as-synthesized nanohybrids are used as accelerants for tri-iodide reduction in dye-sensitized solar cells, resulting in attractive cell efficiency and superior electrochemical stability. The solar cell with low-cost bio-based carbon integrated cobalt/manganese-oxide counter electrode exhibits higher photovoltaic efficiency than that of platinum electrode (7.01% vs. 6.44%). In addition, hybrid catalyst loaded counter electrodes also demonstrate long-term electrochemical stability in I 3 − /I − electrolyte, retaining 97% of its initial efficiency (6.83% / 7.01%) in working cell, after going through multiple cyclic voltammetry scans. The utilization of synergistic effects of high performance constituents and controlled morphology is a key strategy to intensify the catalytic activity , electrochemical stability, and power conversion efficiency in advanced photovoltaics.
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Journal of Materials Research and Technology-JMR&T
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2021
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IF 5.039
Yuyu Liu,Zheng Chen,Xiaoqin Yang,Jinyong Zhang,Zhonggang Sun,Yuzeng Chen,Feng Liu
Different from the reported catalysts such as metallic glasses ribbons and ball-milled high entropy alloy powder, high entropy alloy nanoparticles (HEA NPs) have attracted wide attention for compelling and functional catalytic properties to degrade methylene blue (MB) dye. CoCrXFeNi (X = Al, Cu, Mn) HEA NPs with different loadings were synthesized by impregnation-adsorption method on activated carbon (AC). Nanoscale HEA NPs with maximized configuration mixing entropy are composed of a single solid-solution face-centered cubic (FCC) phase and the nanocomposites show distinctive porous architectures and large specific surface area (average S BET = 632.7 m 2 /g) for 10 wt.% loadings. The reaction rates ( k o b s ) of 10 wt.% CoCrAlFeNi and CoCrMnFeNi HEA NPs-AC for MB degradation are 0.1998 and 0.1830 min −1 and show comparable intrinsic catalytic performance to amorphous ribbons and HEA powders. The HEA NPs can effectively decompose MB molecule via nanoscale galvanic cell effect which provides a promising material in dye decomposition and mineralization.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Richao Niu,Rubing Han,Yin Huang,Liming Dai,Hongan Zhao,Yining Wang,Junwu Zhu,Shaochun Tang,Jingwen Sun
Bimetallic compounds can offer higher electrochemical activity and capacity than monometallic ones owing to their rich chemical valences. Herein, the performance enhancement of monometallic compounds by introducing metal ions was demonstrated, and the effects of different metal ions were investigated. Through introduction of metal ions into LDHs under a hydrothermal environment, one kind of 2D/2D hierarchical CoM-LDH(M=Fe or Mn)/MXene composites were successfully synthesized. It was found that the introduced Fe ions extremely improves the specific capacity and the introduced Mn ions extremely enhances the rate capability of monometallic composite. The fabricated CoFe-LDH/MXene (CF-MX10) electrode exhibits a specific capacity of 808 F g −1 at current density of 0.5 A g −1 , much higher than that of CoMn-LDH/MXene (CM-MX10, 562 F g −1 ) and Co(OH) 2 /MXene (C-MX10, 270 F g −1 ). The high areal capacity or rate capacity are attributed to strong synergistic effect between CoM-LDH and MXene, as well as the introduction of metal ions that change the architecture and the electronic or ionic conductivity , which leads to much improved electrical conductivity and electrochemical stability.
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Journal of Cleaner Production
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2021
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IF 9.297
Weiye Wang,Qingliang Zhao,Jing Ding,Kun Wang,Junqiu Jiang
Bio-electro-Fenton powered by microbial fuel cell (MFC-powered BEF) can in-situ generate and utilize hydrogen peroxide to degrade refractory pollutants. Most of the previous works loaded transition metal on the cathode to participate in the Fenton reaction showed limited electrical or degradation performance. The coupling of alkaline-earth metal (Mg 0 and MgO) and transition metal on cathode could improve the electrochemical and catalytic properties of MFC-powered BEF system, which had not been reported so far. In this research, a novel cathode of Fe–Mn–Mg/carbon fiber (Fe–Mn–Mg/CF) was developed with good polymerization effect of Mg to Fe and Mn, and outstanding production of reactive oxide species (•OH and •O 2 − ), which further improved the overall electricity generation efficiency and enhanced the degradation of pollutants. Accordingly, the maximum power density generated in MFC-powered BEF system with Fe–Mn–Mg/CF cathode was 2.07 times higher than that of the frequently used Fe–Mn/CF. Owing to the superiority of surface holes and MgO in H + adsorption and electron transfer , the integration of Fe, Mn with Mg promoted the in-situ generation of H 2 O 2 and active radicals, resulting in the highest catalytic performance of degrading refractory pollutants . Initial pH, external resistance, initial concentration of contaminant and cycle use frequency of cathode were also evaluated on the degradation efficiency of the BEF system. Furthermore, reaction and degradation mechanisms were proposed from H 2 O 2 production and free radical characterization. Overall, this study provided a novel cathode preparation approach for the MFC-powered BEF system, which vastly promoted its electrochemical and catalytic properties.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
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IF 19.503
Yaowei Lu,Yongxing Wang,Qinghu Tang,Qiue Cao,Wenhao Fang
The synergistic effect in a bimetallic oxide usually plays a vital role in determining the behavior of supported-metal catalysts. We show the unique synergy in a Sn x Mn 1 O y oxide, which can boost the hydrogenation catalysis of supported Pt nanoparticles for selective conversion of levulinic acid (LA) to γ-valerolactone (GVL). On a series of Pt/Sn x Mn 1 O y catalysts with a similar Pt loading ( ca. 0.44 wt%) and a controlled Pt size ( ca. 2.7 nm), the intrinsic TOF presents a volcano-like dependence on Pt 0 sites and Lewis acidity, which is determined by the variable synergistic effect between MnO y and SnO y . The optimal Pt/Sn 0.8 Mn 1 O y catalyst exhibits a high i TOF of 2709 h −1 and achieves 100% selectivity to GVL at 99% conversion of LA at 120 ℃ and 2 MPa of H 2 . DFT calculations demonstrate that the incorporation of Sn can provide a lower energy barrier for the crucial elementary reactions.
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