Symmetry-Basel
·
2023
·Vol. 15
·期 7
·1334
·
IF 2.7
Guolin Song,Chengzhu Shen,David Bassir,Qiulin Li
In this study, a facile strategy of regulated self-assembly synthesis of Mn-MIL-100, using sodium acetate (CH3COONa) as a mono-dentate ligand capping agent (CA), was proposed. The as-prepared product is denoted Mn-MIL-100-CA. The coordination modulation of CH3COONa, led by its interference in the connectivity and symmetry of the metal centers and organic nodes, plays a vital role in the synthesis process. The crystallinity, morphology, topology, and properties of such MOF products were improved, since the self-assembly process of Mn-MIL-100-CA was promoted and regulated effectively. The materials were systematically characterized via XRD, SEM, N2isotherms, XPS, and TGA in terms of crystallization behavior, morphology, topology, chemical composition, and thermal and water stability. The ability of Mn-MIL-100 and Mn-MIL-100-CA to remove methylene blue (MB) from an aqueous solution was investigated using a UV–vis spectrophotometer. The results indicate that with the addition of a molar ratio of 50% CH3COONa, Mn-MIL-100-CA particles developed a regularly symmetrical morphology, i.e., ‘spherical pyramid-like structure’ crystals with a dimension of 2~5 μm. Their specific surface area and pore volume increased by 59.2% and 56.7%, respectively. The increased proportion of Mn3+implies reduced crystal defects and improved crystal structural order and integrity, and therefore an enhanced water stability. Mn-MIL-100-CA exhibited excellent adsorption performance towards MB from aqueous solution. The equilibrium adsorption value was as high as 1079.9 mg/g, which is 44.7% higher than that of Mn-MIL-100 without the addition of CA. The good adsorption capacity and excellent water stability mean that Mn-MIL-100-CA has great potential for the practical removal of MB dye pollutants from water.Keywords:metal organic frameworks;Mn-MIL-100;capping agent;symmetry;self-assembly;methylene blue adsorption
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2023
·Vol. 69
·期 9
·e18149
·
IF 3.7
Yongxiao Tuo,Ying Meng,Qing Lu,Qing Wang,Furong Jia,Yan Zhou,Xiang Feng,Jun Zhang,Xuezhi Duan,De Chen
The enhancement of catalytic activity is always limited by the dilemma in activation and desorption due to Sabatier principle. Locating the Sabatier optimum by manipulating catalyst electronic structure has been a long-standing challenge in heterogeneous catalysis. Herein, we presented a generic strategy to continuously tailor the Pt 5d state occupancy via tuning the Pt O Mn electronic linkage over Al 2 O 3 -confined MnO x islands, aiming at accommodating the C H cleavage and product desorption capabilities in dehydrogenation of liquid organic hydrogen carriers (monocyclic/bicyclic hydrides). Rising Mn valence can decrease the Pt 5d state occupancy through more electron transfer from Pt 5d to O 2p due to the strong π-donation of O 2p to Mn 3d. This will lead to the lower initial C H activation energy barrier while higher product desorption energy barrier. An intermediate Pt 5d filling of ~8.4 in Pt Mn 2 O 3 /Al 2 O 3 enables the balanced level of product desorption and C H activation, thus ensuring a superior dehydrogenation activity. The electron structure-adsorption-performance modulation mechanism described herein provides a benchmark to locate the Sabatier optimum for the metal catalyst design.
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Kunlun Yang,Yuanli Liu,Yizhou Li,Zhen Cao,Chuchen Zhou,Zheni Wang,Xurui Zhou,Shams Ali Baig,Xinhua Xu
In this study, the selective adsorption performance of different Fe-Mn binary oxides (FMBOs) towards Sb(V) in the textile wastewater under different concentrations of coexisting anions, surfactants and dyes were investigated. Results showed that the influences of different anions on the Sb(V) removal followed an order of phosphate > carbonate > sulfate > nitrate > chloride. The frequently-used organic acid of acetate was found to have insignificant effect. The coexisting surfactant with sulfonic groups could have adverse effect on the removal due to sulfonic groups could compete the adsorptive sites on Fe oxides with Sb(V). While the quaternary ammonium surfactant might have minor effect. The influences of the three widely used dyes on the Sb(V) adsorption decreased in the following order: reactive black-5 >acid orange-7> disperse blue-60, which confirmed that the dyes with sulfonic groups would have relatively higher effect. The selective adsorption capacities of Sb(V) by FMBOs followed an order of FMBO 3 > FMBO 5 >FMBO 10 > FMBO 20 >PFO. Fixed-bed column adsorption supplied useful parameters and evidently indicated that the cyclic utilization of FMBO 3 was cost-efficient for practical dynamic Sb(V) removal. The Sb(V) removal by FMBO 3 from real textile wastewater can simultaneously improve the removal efficiency, stabilize pH and prevent the increase of iron concentration as compared to the traditional coagulation, further demonstrating the high practical applicability of FMBO 3 .
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2019
·Vol. 645
·期 10
·745-751
·
IF 1.337
Xiaofang Li,Yuandong Wu,Dajiang Mei,Thomas Doert
Three new alkali metal transition metal sulfate-oxalates, RbFe(SO 4 )(C 2 O 4 ) 0.5 · H 2 O and Cs M (SO 4 )(C 2 O 4 ) 0.5 · H 2 O ( M = Mn, Fe) were prepared through hydrothermal reactions and characterized by single-crystal X-ray diffraction, solid state UV/Vis/NIR diffuse reflectance spectroscopy, infrared spectra, thermogravimetric analysis, and powder X-ray diffraction. The title compounds all crystallize in the monoclinic space group P 2 1 / c (no. 14) with lattice parameters: a = 7.9193(5), b = 9.4907(6), c = 8.8090(6) Å, β = 95.180(2)°, Z = 4 for RbFe(SO 4 )(C 2 O 4 ) 0.5 · H 2 O; a = 8.0654(11), b = 9.6103(13), c = 9.2189(13) Å, β = 94.564(4)°, Z = 4 for CsMn(SO 4 )(C 2 O 4 ) 0.5 · H 2 O; and a = 7.9377(3), b = 9.5757(4), c = 9.1474(4) Å, β = 96.1040(10)°, Z = 4 for CsFe(SO 4 )(C 2 O 4 ) 0.5 · H 2 O. All compounds exhibit three-dimensional frameworks composed of [ M O 6 ] octahedra, [SO 4 ] 2– tetrahedra, and [C 2 O 4 ] 2– anions. The alkali cations are located in one-dimensional tunnels.
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2019
·Vol. 7
·期 23
·1901082
·
IF 7.125
Daqin Chen,Su Zhou,Feifan Tian,Haitao Ke,Naizhong Jiang,Shujin Wang,Yongzhao Peng,Yue Liu
Recently, Mn 2+ -doped CsPb(Cl/Br) 3 perovskite nanocrystals (NCs), showing the advantages of dual-color emissions via exciton-to-dopant energy transfer and reduced usage of toxic Pb 2+ heavy metal ions by nontoxic Mn 2+ substitution, are widely explored. However, photoluminescence quantum yields (PLQYs) for Mn 2+ -doped CsPb(Cl/Br) 3 NCs still need to be further improved. Here, a halogen-hot-injection strategy is developed to prepare Mn:CsPb(Cl 0.6 Br 0.4 ) 3 NCs with the maximal PLQY of 65%. With this method, intense blue narrowband emission from excitonic recombination and orange broadband emission from Mn 2+ 4 T 1 → 6 A 1 transition can be simultaneously achieved. The competitive luminescence between perovskite NCs and Mn 2+ dopants is systematically investigated by controlling the injected halogen types and ratios. As a proof-of-concept experiment, the present Mn 2+ -doped CsPb(Cl/Br) 3 perovskite NCs with highly efficient dual-color emissions are demonstrated to be applicable as color converter in UV-excitable solid-state lighting.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xinxin Zhang,Kang Hu,Xuliang Zhang,Wajid Ali,Zhijun Li,Yang Qu,Hao Wang,Qingyang Zhang,Liqiang Jing
In this work, an in-situ way has been developed to achieve the co-modification of highly-dispersed Mn and Cu oxides to g-C 3 N 4 nanosheets for efficient CO 2 reduction. The Mn & Cu amount-optimized nanosheets exhibit the improved photocatalytic activity for CO 2 reduction to CO and CH 4 both by 3 times compared with the generally-bulk g-C 3 N 4 , mainly attributed to the nanosheet structure and to the roles of modified Mn and Cu oxides. Based on the transient-state surface photovoltage responses, transient-state photoluminescence spectra, and electrochemical measurements, it is confirmed that the modified Mn and Cu oxides could respectively capture the photogenerated holes and electrons, and provide the catalytic functions for water oxidation and CO 2 reduction. Remarkably, the simultaneous introduction of Mn and Cu oxides shows an obvious synergistic effect on the improvement of photocatalytic activity for CO 2 reduction. This work provides a feasible way to synthesize high-activity g-C 3 N 4 -based photocatalysts for energy production.
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2019
·
IF 2.781
Tianyu Cai,Li Yuan,Guozheng Liang,Hong Wang,Aijuan Gu
Achieving lower curing temperature and higher properties has been the significant target for developing heat-resistant thermosetting resins . Herein, a facile covalent approach has been built to fabricate functionalized graphene oxide (HBP@GO/MnF) through grafting hyperbranched polysiloxane (HBP) and hybridizing metal–organic framework with Mn 2+ (MnF), which has been proved to have desirable abilities of simultaneously decreasing curing temperature as well as improving toughness and stiffness while maintaining the biggest advantage (low dielectric loss) and high thermal resistance of cyanate ester (BCy) resin. A comparative study demonstrates that the activation from HBP endows HBP@GO/MnF with good dispersion in BCy resin and provides strong interfacial action between HBP@GO/MnF and BCy resin. When the loading of HBP@GO/MnF is as small as 0.5 wt%, the peak temperature of curing reduces to 278 °C from 313 °C of BCy, meanwhile severally about 60%, 98%, 120% and 93% increased flexural strength , flexural modulus, impact strength and fracture toughness are achieved. In addition, all modified BCy resins post-cured at 220 °C/4 h have better mechanical properties and higher heat resistance than pure BCy resin post-cured at 240 °C for 4 h. These outstanding performances prove that HBP@GO/MnF is promising filler for fabricating new resins with higher performances and better curing feature.
✓ 已验证
产品关联
DOI
高影响因子
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.
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 10
·1-8
·
IF 5.705
Pang Jiawei,Lu Yuexiang,Gao Xinyu,Song Panshu,Yang Fengyi,Liu Yueying
A selective phosphorescent on-off-on probe with long decay lifetime has been designed for the detection of pyrophosphate ions (PPi). The detection scheme is based on the use of europium(III)-modulated Mn(II)-doped ZnS quantum dots capped with N-acetyl-L-cysteine. Both the aggregation of quantum dots and electron transfer induced by Eu(III) ions cause phosphorescence to be quenched (“off” state). Phosphorescence is, however, restored on addition of PPi to the system (“on” state). The effect is attributed to the removal of Eu(III) from the carboxy groups on the surface of the quantum dots owing to the stronger interaction between PPi and Eu(III). A linear relationship exists between phosphorescence intensity (best measured at excitation/emission wavelengths of 316/594 nm) and PPi concentration in the 400 nM to 6000 nM with a detection limit of 145 nM. An additional attractive feature is provided by the long-lived phosphorescence (1920 μs) of the quantum dots. It can be used to eliminate interference by short-lived fluorescence in biological samples by performing time resolved measurements. The probe was applied to the determination of PPi in spiked in urine samples and gave recoveries in the range from 98 to 105% with RSDs of <2.0%.
Schematic of a long-lived phosphorescent on-off-on probe for the sensitive and selective detection of pyrophosphate ions (PPi). It is based on the use of Eu(III)-modulated Mn(II)-doped ZnS quantum dots (QDs). Phosphorescence is quenched of QDs after the addition of Eu 3+ but restored after the addition of PPi.
✓ 已验证
产品关联
DOI
PubMed
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.
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Xin Zhao,Lei Huang,Hongrui Li,Hang Hu,Jin Han,Liyi Shi,Dengsong Zhang
Different transition metals were used to modify V 2 O 5 -based catalysts (M-V, M = Cu, Fe, Mn, Co) on TiO 2 via impregnation, for the selective reduction of NO with NH 3 . The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO 2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N 2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO 2 showed the highest activity and N 2 selectivity at 225–375 °C. The results of X-ray photoelectron spectroscopy, NH 3 -temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO 2 /H 2 O durability of Cu-V/TiO 2 make it a candidate to be a NO x removal catalyst for stationary flue gas.
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yang Yao,Lin Cao,Haoyue Yang,Raz Muhammad,Yingjie Ren,Xinjiang Luo,Fayaz Hussain,Bing Liu,Minmin Mao,Hadi Barzegar Bafrooei,Ehsan Taheri-Nassaj,Kaixin Song
In this study, high-entropy Mg 1.8 R 0.2 Al 4 Si 5 O 18 (R Ni, Ni 1/2 Co 1/2 , Ni 1/3 Co 1/3 Zn 1/3 , Ni 1/4 Co 1/4 Zn 1/4 Cu 1/4 , Ni 1/5 Co 1/5 Zn 1/5 Cu 1/5 Mn 1/5 ) cordierite ceramics based on equimolar ratios were designed and synthesized through the solid-state reaction technique at high temperatures. The effect of various R-ionic substitutions at the octahedral site and their relationship with ionic polarization, chemical bonding, and configurational entropy were explored. These factors have greatly affected the microwave dielectric properties of Mg 1.8 R 0.2 Al 4 Si 5 O 18 ceramics. The presence of cation radius mismatch and electronegativity mismatch at [MgO 6 ]-octahedron lattice sites revealed lattice distortion resulting from multiple cation substitutions. As the entropy values increased, the temperature stability of microwave dielectric properties of Mg 1.8 R 0.2 Al 4 Si 5 O 18 ceramics improved. For R Ni 1/2 Co 1/2 , a higher Q×f of approximately 73,658 GHz @ 13 GHz, with ɛ r ∼4.44 and τ f ∼ −23.9 ppm/°C was obtained. In the case of R Ni 1/5 Co 1/5 Zn 1/5 Cu 1/5 Mn 1/5 , a near zero τ f (−10.7 ppm/°C), ɛ r = 4.68 and Q×f = 35,478 GHz @13 GHz were achieved, making it potentially suitable for practical applications.
✓ 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）