CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Xiaoning Wang,Xuejin Li,Tonghui Cai,Yongpeng Cui,Dongqing Kong,Jing Xu,Haoyu Hu,Yesheng Wang,Han Hu,Xiuli Gao,Yanpeng Li,Qingzhong Xue,Zifeng Yan,Lianming Zhao,Wei Xing
Designing electrocatalysts for hydrogen oxidation reaction (HOR) in alkaline media is crucial but challenging. Among all available electrocatalysts, Ni-based materials are recognized as the most potential precious-metal-free electrocatalysts for HOR. However, they still suffer from serious problems including low activity and poor stability. In this work, a synergistic chemical anchoring and electronic structure regulation strategy is proposed to gain both high electrocatalytic activity and stability for Ni-based HOR catalyst. N-doped graphite nanoflakes (N-GFs) support with abundant N anchoring sites can stabilize the loading of Ni-based active species, giving rise to an excellent stability of the catalyst. Meanwhile, the rationally designed heterostructure in the active Ni 3 N/Ni can trigger the electron transfer across the heterointerface, which optimizes the binding energy of the reaction intermediates, resulting in an accelerated the Volmer reaction. Benefited from the rational design, Ni 3 N/Ni/N-GFs exhibits excellent mass activity (42.7 A g Ni -1 at the overpotential of 50 mV) and stability (more than 24 h continuous operation). Moreover, the Ni 3 N/Ni heterostructure performs better in HOR electrocatalysis than individual Ni or Ni 3 N. These experimental results are rationalized by the theoretical simulations, which demonstrate that the heterostructure effectively weakens the hydrogen adsorption, optimizes the hydroxyl adsorption, and decreases the water formation reaction barrier.
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JOURNAL OF SOLID STATE CHEMISTRY
·
2021
·
IF 3.498
Muge Shele,Fei-Yan Qi,Xin-Yu Tian,Yong-Sheng Bao,Menghe Baiyin
Three organic-decorated quaternary TM-Cd-Sb-Se (TM = Zn, Mn, Fe) compounds were prepared under tris (2-aminoethyl) amine conditions by solvent method, namely, [Zn(tren)] 2 CdSb 2 Se 6 ( 1 ), [Mn(tren)]CdSb 2 Se 5 ( 2 ) and [Fe(tren)]Cd 2 SbSe 5 ( 3 ) [tren = tris (2-aminoethyl) amine)]. The single-crystal X-ray diffraction analyses showed that the three compounds structures were 0-D {[Zn(tren)] 2 CdSb 2 Se 6 } ( 1 ) cluster, 1-D {[Mn(tren)]CdSb 2 Se 5 } ( 2 ) ribbon and 2-D {[Fe(tren)]Cd 2 SbSe 5 } ( 3 ) layered. A series of characterizations of these compounds were performed, as estimated from the adsorption spectra, the band gaps of 1 , 2 and 3 are 2.09, 1.78 and 1.91eV, respectively. Photoluminescence experiments show that compounds 2 and 3 exhibit luminescent properties. And the thermal stability of these compounds was tested by thermogravimetric and differential scanning calorimetry .
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CATALYSIS LETTERS
·
2021
·Vol. 151
·期 8
·2339-2345
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IF 3.186
Zhang Linfeng,Zheng Jing,Zou Wenya,Shu Yongqi,Yang Weiran
Abstract 3-iodopropionic acid (3-IPA) can be efficiently synthesized from the glycerol derivative glyceric acid (GA), which is a potential biomaterial-based platform molecule. In this report, ethyl 3-iodopropionate was rapidly dimerized to diethyl adipate in a microwave reactor using NiCl 2 ·6H 2 O as a catalyst, co-catalyzed by Mn and the 1, 10-Phenanthroline monohydrate ligand. Under the optimum reaction conditions, diethyl adipate can be obtained with 84% yield at 90 °C in just 5 min. Diethyl adipate was hydrolyzed to obtain the adipic acid (AA) in 89% yield with an acid catalyst. AA is an important chemical and a monomer for producing a wide range of high-performance polymeric substances. This rapid coupling method is also applicable to other alkyl halides. Graphic Abstract
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Nanomaterials
·
2020
·Vol. 10
·期 9
·1745
·
IF 4.324
Ze Sun,Liuting Zhang,Nianhua Yan,Jiaguang Zheng,Ting Bian,Zongming Yang,Shichuan Su
Magnesium hydride (MgH2) has been considered as a potential material for storing hydrogen, but its practical application is still hindered by the kinetic and thermodynamic obstacles. Herein, Mn-based catalysts (MnCl2and Mn) are adopted and doped into MgH2to improve its hydrogen storage performance. The onset dehydrogenation temperatures of MnCl2and submicron-Mn-doped MgH2are reduced to 225 °C and 183 °C, while the un-doped MgH2starts to release hydrogen at 315 °C. Further study reveals that 10 wt% of Mn is the better doping amount and the MgH2+ 10 wt% submicron-Mn composite can quickly release 6.6 wt% hydrogen in 8 min at 300 °C. For hydrogenation, the completely dehydrogenated composite starts to absorb hydrogen even at room temperature and almost 3.0 wt% H2can be rehydrogenated in 30 min under 3 MPa hydrogen at 100 °C. Additionally, the activation energy of hydrogenation reaction for the modified MgH2composite significantly decreases to 17.3 ± 0.4 kJ/mol, which is much lower than that of the primitive MgH2. Furthermore, the submicron-Mn-doped sample presents favorable cycling stability in 20 cycles, providing a good reference for designing and constructing efficient solid-state hydrogen storage systems for future application.Keywords:hydrogen storage;MgH2;Mn-based catalysts;catalytic effect;reversibility
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Lanlan Gan,Qian Su,Zhangbao Chen,Xiaoming Yang
Detections of carcinogen and vitamins are generally recognized to be meaningful, especially for nitrites (NO 2 − ) and ascorbic acid (AA). Here blue-fluorescence carbon dots (CDs) with the quantum yield of 11.83% were successfully synthesized by using folic acid and nicotinic acid, and their surfaces were identified to be abundant in the functional groups of amide, carboxyl and hydroxyl. Importantly, the amide on the surfaces of CDs showed the interactions with the nitrites and formed the complex, thus resulting in their quenched fluorescence. To be specific, the fluorescence intensity of CDs proportionally decreased by adding the increased amounts of NO 2 − from 8 to 800 μM, and achieved the detection of NO 2 − at a detection limit of 21.2 µM. Moreover, further introducing ascorbic acid could prevent CDs with NO 2 − to form the complex and recover their fluorescence, and thus providing the new avenue of assaying AA with the generally favorable linear range of 0.1–800 μM, while its related detection limit was 50 µM. In addition, the synthesized CDs exhibited the satisfactory sensitivity toward different pH values, demonstrating their potential of sensing pH. Consequently, the proposed CDs here may provide a new way of monitoring NO 2 − and AA in the target samples.
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ANALYST
·
2020
·Vol. 145
·期 7
·2661-2668
·
IF 3.978
Hongzhi Lu,Shoufang Xu
A simple core shell structured fluorescent sensor was constructed to realize simultaneous detection of hexavalent and trivalent chromium ions. Briefly, blue-carbon dots (b-CDs) were embedded into a silica sphere, then a Cr(III) imprinted silica layer doped with red-CDs (r-CDs) was coated onto the b-CDs@SiO2. Cr(VI) can selectively quench b-CDs based on the inner filter effect and Cr(III) can selectively quench r-CDs based on electron transfer with the aid of the ion imprinting technique. In this strategy, it was not necessary to reduce Cr(VI) to Cr(III) or oxidize Cr(III) to Cr(VI), the chromium speciation of both can be detected simultaneously. When Cr(VI) was detected in the blue channel, the fluorescence intensity quenching effect was seen at 440 nm, and was linear from 0.01 to 10.0 μM, with a detection limit of 3.8 nM. For the detection of Cr(III) in the red channel, the fluorescence intensity quenching effect was seen at 605 nm, and was linear from 0.1 to 15.0 μM, with a detection limit of 46 nM. This strategy enjoyed the advantages of simple construction, convenient detection, good selectivity and high sensitivity.
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Journal of Energy Chemistry
·
2020
·
IF 7.216
Jia Sun,Lei Du,Baoyu Sun,Guokang Han,Yulin Ma,Jiajun Wang,Hua Huo,Pengjian Zuo,Chunyu Du,Geping Yin
ABO 3 -type perovskite oxides (e.g., LaCoO 3 ) with flexible and adjustable A- and B-sites are ideal model catalysts to unravel the relationship between the electronic structure and electrocatalytic activity (e.g., oxygen reduction/evolution reactions, ORR/OER). It has been well understood in our recent work that the secondary metal dopant at B-site (e.g., Mn in LaMn x Co 1 −x O 3 ) can regulate the electronic structure and improve the ORR/OER activity. In this work, the Mn-Ni pairs are employed as the dual dopant in LaMn x Ni y Co z O 3 ( x + y + z = 1) catalysts toward bifunctional ORR and OER. The structure–property relationships between the triple metal B-site (Mn, Ni and Co) and the electrochemical performance are particularly investigated. Compared to the individual Mn doping (e.g., LaMnCoO 3 (Mn:Co = 1:3) catalyst), the dual Mn-Ni doping significantly improves the ORR mass activity@0.8 V by 1.54 times; meanwhile, the OER overpotential@10 mA cm −2 is reduced from 420 to 370 mV, and the OER current density at 1.55 V is increased by 2.43 times. Reasonably, the potential gap between E ORR @-1 mA cm −2 and E OER @10 mA cm −2 is achieved as only 0.76 V by using the optimal LaMn x Ni y Co z O 3 ( x : y : z = 1:2:3) catalyst. It is revealed that the dual Mn-Ni dopant efficiently optimizes electron structures of the LaMnNiCoO 3 (1:2:3) catalyst, which not only decreases the e g orbital electron number, but also modulates the O 2p-band closer to the Femi level, accounting for the enhanced bifunctional activity.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Miao Fu,Zhiying Feng,Jing Wang,Ying Zhu,Lanlan Gan,Xiaoming Yang
Room-temperature phosphorescence (RTP) materials have harvested enormous attention owing to their advanced optical properties, providing their possibility of the wider applications. Here, we designed a facile strategy to synthesize phosphorus and nitrogen co-doped carbon dots, while creatine provided the carbon and nitrogen source (CDs@creatine). Meanwhile, the as-prepared CDs@creatine exhibited the bright blue fluorescence in aqueous suspension, and showed the green RTP while being fixed on the filter paper. Significantly, the fluorescence of CDs@creatine was quenched by the introduction of warfarin, whereas their RTP was simultaneously enhanced. Specifically, their fluorescence reduction was mainly ascribed to static quenching effect (SQE) and inner filter effect (IFE). In addition, the abundant hydroxyl groups on the surface of CDs@creatine interacted with the carbonyl groups of warfarin to form hydrogen bonds which rigidified the excited triplet against the non-radiative transition, and thus leading to their enhanced phosphorescence. Therefore, a dual-channel detecting strategy of warfarin has been successfully proposed with the fluorescent linear range from 8 × 10 −3 to 8 × 10 −7 M and phosphorescent linear range of 2 × 10 −5 to 1 × 10 −8 M, which established a new way of assaying warfarin. Besides, CDs@creatine served as both fluorescent and phosphorescent ink, and were applied for painting and information encryption.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 36
·36933-36941
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IF 2.914
Chen Jun,He Jinjia,Wang Xiaoping,Hrynsphan Dzmitry,Wu Jiali,Chen Jianmeng,Yao Jiachao
Conversion of Fe II (EDTA)-NO or Fe III (EDTA) into Fe II (EDTA) is a key process in a wet flue gas denitrification technology with Fe II (EDTA) solution. In this work, the stoichiometry, kinetics, and thermodynamics of Fe II (EDTA)-NO reduction by Mn powder were investigated. We first studied the Fe II (EDTA)-NO reduction and product distribution to speculate a possible stoichiometry of Fe II (EDTA)-NO reduction by Mn powder. Then, the effects of major influencing factors, such as pH value, temperature, and Mn concentration, were studied. The pseudo-second-order model was established to describe the Fe II (EDTA)-NO reduction. Simultaneously, according to Arrhenius and Eyring-Polanyi equations, the reaction activation energy ( E a ), enthalpy of activation (∆ H ‡ ), and entropy of activation (∆ S ‡ ) were calculated as 23.68 kJ/mol, 21.148 kJ/mol, and − 149.728 J/(k mol), respectively. Additionally, simultaneous reduction of Fe III (EDTA) and Fe II (EDTA)-NO was investigated to better study the mechanism of Fe II (EDTA) regeneration, suggesting that there was a competition between the two reduction processes. Finally, a simple schematic mechanism of NO absorption by Fe II (EDTA) combined with regeneration of manganese ion and ammonium was proposed. These fundamental researches could offer a valuable guidance for wet flue gas denitrification technology with Fe II (EDTA) solution.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 47
·27016-27022
·
IF 10.733
Yang Lv,Yiyang Liu,Ting Feng,Jin Zhang,Shanfu Lu,Haining Wang,Yan Xiang
Aqueous organic redox flow battery (AORFB) is one of the attractive technologies for renewable energy storage. The electronic effect or steric effect of the functional groups are commonly under discussion to screen the appropriate organic electrolytes for AORFBs. However, the role of structural reorganization on the electron transfer process of organic electrolytes in AORFBs is still not clear. In this work, we study the electrochemical properties of three bipyridine derivatives as organic electrolytes for AORFBs. The influence of structural reorganization on the electron transfer is investigated by changing the type and position of the functional groups of the bipyridine derivatives. Density functional theory (DFT) calculation reveals that the molecular structures of three molecules have a noticeable difference due to the steric effect of the functional groups. Furthermore, the rate constants of 1,1′-ethylene-2,2′-bipyridinium dichloride and methyl viologen are significantly higher than that of 1-methyl-2-(1-methylpyridin-1-ium-2-yl)pyridin-1-ium dichloride due to the much lower reorganization energy. As a result, a single battery using 1,1′-ethylene-2,2′-bipyridinium dichloride as the organic electrolyte shows excellent cell performance with the energy efficiency of 67.18% and excellent cycling stability with a capacity retention of 99.95% per cycle at the current density of 100 mA cm−2.
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ACS Omega
·
2019
·
IF 2.584
Wei Sun,Qi Sun,Qiang Zhao,Luminita Marin,Xinjian Cheng
In this work, SiO2 microspheres were first prepared by a conventional Stöber method and then etched by NaOH solution to obtain porous ones. By tuning the degree of etching, specific surface area of SiO2 microspheres could be controlled. Then, small fluorescent molecules are synthesized and incorporated onto the surface and/or pores of the SiO2 via layer-by-layer reaction to obtain fluorescent microspheres, namely, SiO2–NH2–BODIPY (SiNBB), SiO2–NH2–BODIPY–indole–benzothiazole (SiNBIT), and SiO2–NH2–BODIPY–indole–benzoxazole (SiNBIO). The as-prepared microspheres SiNBB exhibit highly sensitive and selective recognition ability for Hg2+ and Pb2+. When SiNBB encounters Hg2+ and Pb2+, the fluorescence intensity of SiNBB is increased up to fivefold. SiNBIT and SiNBIO are solely sensitive to Hg2+, and both have a single high sensitivity to recognize Hg2+. The adsorption efficiency of Hg2+ by the three fluorescent microspheres SiNBB, SiNBIT, and SiNBIO reached 2.91, 0.99, and 0.98 g/g of microspheres, respectively. Experimental results of A549 cells and zebrafish indicate that the fluorescent microspheres are permeable to cell membranes and organisms. The distribution of Hg2+ in the brain of zebrafish was obtained by the fluorescence confocal imaging technique, and Hg2+ was successfully detected in A549 cells and zebrafish.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2019
·
IF 2.931
Shengmei Song,Fan Liang,Minglu Li,Fangfang Du,Wenjuan Dong,Xiaojuan Gong,Shaomin Shuang,Chuan Dong
A fluorescent sulfur and nitrogen dual-doped carbon dots (S,N-CDs) was prepared by a simple and one-step acid-base neutralization and exothermic carbonization method. Hexavalent chromium (Cr(VI)) could effectively quench the fluorescence of S,N-CDs based on inner filter effect (IFE) and dynamic quenching, whereas ascorbic acid (AA) could recover the fluorescence of S,N-CDs/Cr(VI) because of IFE weakening. So an “on-off-on” and label-free nano-probe consecutive determination of Cr(VI) and AA was constructed. This nano-probe system demonstrated excellent selectivity and sensitivity to Cr(VI) and AA with linear range of 0.065–198 μmol/L (3.38–10,296 μg/L) and 6.6–892 μmol/L (1.16–157 mg/L), respectively. Meanwhile, the as-prepared S,N-CDs possess low toxicity and could be used for multi-color cell imaging in SMMC 7721 cells. More importantly, this nano-probe was successfully employed for detection of Cr(VI) in tap water and AA in food samples. In view of its simple detection condition, rapid response, wide linear range, low detection limit and inexpensive instrument, the as-constructed nano-probe system could have a wide range of potential application, including water quality monitoring and evaluation, food inspection and testing and biomedical analysis.
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