International Journal of Applied Ceramic Technology
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2024
·
IF 1.8
Shuaijun Yang,Mei Wang,Yetong Lv,Huilin Sheng,Yexia Qin
Oxidation resistance is crucial to the potential applications of high-entropy carbides (HECs) at elevated temperatures. Here, we realize the exploration of (Hf, Ta, Zr, Cr)C high-entropy carbides (HEC-TM, TM = Hf, Zr, Ta, and Cr) with good oxidation resistance by optimizing their compositions. To be specific, 21 kinds of HEC- x TM ( x = 0–25 mol%) samples are fabricated by a high-throughput ultrafast high-temperature sintering technique, followed by oxidation testing at 1673 K for 30 min. Among all the HEC samples, the as-fabricated HEC-0Zr samples are proved to possess the best oxidation resistance with an oxidation depth of only 53 µm. Further study on isothermal oxidation kinetics demonstrates that the as-fabricated HEC-0Zr samples follow a linear oxidation law. The good oxidation resistance of the as-fabricated HEC-0Zr samples is believed to result from the (Ta, Me) 2 O 5 phase with a low melting point, which can promote the densification of the oxide layer. This research opens up a new way for efficiently discovering new HECs for extreme applications.
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高影响因子
MICROCHEMICAL JOURNAL
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2024
·
IF 4.9
Xuanqi Hao,Xiao Zhang,Jianrong Wang,Chenchen Liu,Chuanhao Li,Ping Yang
To create fluorescent sensors for Cr (VI) and l-arginine detection, blue-emitting carbon dots (CDs, named as M-CDs) were prepared via a solvothermal synthesis by using m-phenylenediamine. The introduction of sulfuric acid changed the blue-emitting of CDs into green-emitting (named as S-CDs), in which the photoluminescence (PL) peak wavelengths of samples M-CDs and S-CDs were 450 and 540 nm, while their PL efficiencies were 21.7 and 84.2 % respectively. Sulfuric acid resulted in the average fluorescent lifetime of the CDs was prolonged into 8.19 from 4.65 ns. The photo and thermal stable tests demonstrated that theses CDs revealed excellent stability. Meanwhile, CDs flexible films with bright blue- and green-emitting were prepared utilizing the favorable solubility of CDs in polar solvents. Mono-dispersed CDs as luminescent materials demonstrated it promising prospects in luminescent devices field. Furthermore, M-CDs exhibited excellent selectivity towards Cr(VI) and l-arginine. The detected limit (0.86 μM for Cr(VI) and 0.43 μM for l-arginine) was determined by assessing the response of M-CDs to various concentrations of Cr(VI) ion and l-arginine solutions. These bright CDs revealed great potential for accurate detection of Cr(VI) and l-arginine.
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CHEMICAL ENGINEERING JOURNAL
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2025
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IF 13.2
Yulong Xiang,Xinbin Ji,Xiaoli Dong,Yu Wang,Nan Zheng,Chundong Liu,Menglin Wang,Chumin Yan
Photoreduction of toxic Cr(VI) in wastewater to less toxic Cr(III) presents an effective approach to address the environmental issues. Nevertheless, the photocatalytic performance of these photocatalysts is severely constrained by their narrow light absorption range and the rapid recombination of photo-generated electrons and holes. Herein, DUT-67/Fe 2 O 3 heterojunction photocatalysts were prepared by a simple mechanical grinding method. The formation of DUT-67/Fe 2 O 3 heterostructures not only increased the specific surface area and light absorption range, but also improved the separation of photogenerated charge carriers. Compared to the pristine DUT-67, DUT-67/Fe 2 O 3 exhibited significantly improved photocatalytic performance in the reduction of Cr(VI), achieving a reduction efficiency of up to 94 % within 40 min. Active species trapping experiments identified that electrons served as the primary species in the photocatalytic process. Coupled with electron spin resonance and density functional theory (DFT) calculations, a comprehensive mechanism for the photocatalytic reduction of Cr(VI) by DUT-67/Fe 2 O 3 Z-scheme heterojunction was proposed. This work offers new insights into the underlying mechanisms involving in the interfacial charge transfer and Cr(VI) photoreduction processes.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2017
·Vol. 43
·期 9
·5217-5228
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IF 1.369
Qin Na,Jing Kaiqiang,Chen Rui,Xiong Jinhua,Liang Ruowen,Li Zhaohui,Wu Ling
Abstract SnS 2 /SnO 2 nanocomposites have been successfully prepared via a hydrothermal method using electrospun SnO 2 nanotubes as both substrates and reactants. The ratios of the nanocomposites are controlled by varying the concentration of thioacetamide during the solvothermal synthesis processes. The as-prepared SnS 2 /SnO 2 nanocomposites exhibit considerable improvement on the photocatalytic activities for the reduction of aqueous Cr(VI) under visible light irradiation. Their photoactivities are also much higher than that of SnS 2 nanoplates and a physical mixture of SnO 2 and SnS 2 . In particular, the SnS 2 /SnO 2 -B sample exhibits the highest photocatalytic activity. After visible light irradiation for 60 min, the reduction rate has reached about 100%. The photoelectrochemical analyses further show that the high photocatalytic activity of the SnS 2 /SnO 2 -B sample can be ascribed to the unique structural features and the intimate interfacial contact between SnS 2 and SnO 2 , which is more effective separation of the photo-generated carriers. Graphical Abstract
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Analytical Methods
·
2016
·Vol. 8
·期 28
·5684-5689
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IF 1.915
Na Xu,Quan Zhu,Xiang-Yue Kong,Lei Meng
Polyethyleneimine protected silver nanoclusters (AgNCs@PEI) were prepared and used as high sensitive fluorescence probes for detecting Cr(VI). The mechanism worked by combining Cr(VI) with a primary amine of AgNCs@PEI causing electrostatic interaction, which led to the aggregation of AgNCs, as well as fluorescence quenching. Compared with other fluorescence sensors of Cr(VI) detection, this probe shows excellent performances: (i) The fluorescence probe responds immediately after adding Cr(VI). (ii) The fluorescence quenching efficiency of AgNCs@PEI was linearly related to the concentration of Cr(VI) over the range from 0.5 nM to 25 μM. (iii) The limit of detection is as low as 0.05 nM. (iv) High selectivity for Cr(VI) in 14 types of normal metal ions were obtained and especially the probe can be applied in both acidic and alkaline conditions (pH 2.0–11.0). (v) The probe can be used for the determination of Cr(VI) in real samples with satisfactory results. Therefore, the fluorescence probe is of practical significance and application prospects.
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RSC Advances
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2016
·Vol. 6
·期 64
·59292-59298
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IF 3.289
Jianqiao Zhang,Huan Chen,Zi Chen,Jiaojie He,Wenxin Shi,Dongmei Liu,Huizhong Chi,Fuyi Cui,Wei Wang
A high-performance, cost-effective and spongeous adsorbent was rationally designed for Cr(VI) removal from aqueous solution based on PPy modified natural quasi two-dimensional (2D) structures. Core of corncobs, a kind of agricultural waste composed of quasi 2D sub-micro sheets, has a unique macroporous spongeous microstructure. In consideration of the unique chemical structure of polypyrrole (PPy) and microstructure of the natural sponge, we constructed the microstructured spongeous adsorbents. The PPy active layer provided reactive sizes to detoxifies Cr(VI) ions by ion-exchange. While the spongeous microstructure provided by the microsheets could enhance the adsorption performance by increasing active areas and facilitating the access of pollutants inside the adsorbents. Compared with artificial nano-powder adsorbents, CC–PPy displayed larger advantage in separation process and fabrication/operation cost. Compared with other bulk-style PPy composites, the adsorption capacity of CC–PPy was several times higher. In addition, the regeneration and stability of CC–PPy was outstanding with no loss in the adsorption to Cr(VI) even after 3 adsorption–desorption cycles. The present development provides a solution to design highly efficient and cost-effective water treatment agents.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2017
·Vol. 55
·期 20
·3404-3412
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IF 2.952
Yulong Jin,Ning Zhao,Ruihua Cheng,Xuelian He,Zhen Liu,Dalin Dong,Yuezhen Bin,Xiaowei Chen,Liangbin Li,Boping Liu
Bimodal ultra-high-molecular-weight polyethylene (UHMWPE)/high-density polyethylene (HDPE) in-reactor blends (IRBs) are produced by the bimetallic catalysts, which are synthesized through co-supporting silylchromate and vanadium-oxide-based catalysts on silica or alumina, zirconia and titania-modified silica. After support modification, the activities of the catalysts for ethylene polymerization are substantially enhanced. The IRBs produced by the modified catalysts also contain more UHMWPE and low-molecular-weight polyethylene (LMWPE) fractions, and have much broader molecular weight distribution (MWD). The homogeneous nature of the IRBs is preliminarily confirmed by the differential scanning calorimetry melting curves, showing unique melting peak in both nascent and recrystallized states. The rheological results reflect that the viscosity of the IRBs is reduced more or less when compared with UHMWPE. The distinct elastic dominance of the IRBs is also observed, implying the UHMWPE characteristics in the IRBs. In addition, the intimate mixing of the IRBs is further verified by the similar slopes of Han curves for the polyethylene (PE) samples. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3404–3412
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RSC Advances
·
2016
·Vol. 6
·期 93
·90232-90238
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IF 3.289
Xiao-Fang Liu,Hu Li,Heng Zhang,Hu Pan,Shan Huang,Kai-Li Yang,Song Yang
Catalytic ethanolysis of furfuryl alcohol (FA) to ethyl levulinate (EL) with MIL-101(Cr)–SO3H, prepared by simple one-pot hydrothermal treatment, is presented for the first time. The as-prepared catalyst with high surface area, hydrothermal and chemical stability, good dispersion, and feasible accessibility of –SO3H Brønsted acid sites was found to show superior performance to other sulfonic acid-functionalized solid catalysts. Besides the special textural properties, the obtained good catalytic activity of 79.2% EL yield and 100% FA conversion were also dependent on the density and strength of the Brønsted acid and the reaction parameters. A slight loss of catalytic activity after five consecutive recycles and the hot filtration experiment confirmed the good stability of MIL-101(Cr)–SO3H. Two coexisting reaction paths for the ethanolysis of FA to EL catalyzed by MIL-101(Cr)–SO3H were proposed, wherein 2-ethoxymethylfuran (2-EMF) was observed to be the dominant intermediate.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2015
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IF 2.999
Qian Qi,Yan Liu,Hui Zhang,Yinsheng Li,Hanqin Liang,Zhengren Huang
SiC p /Hastelloy composites were fabricated by pressureless Ti-activated infiltration process. The wetting and infiltration behaviors of Hastelloy on the SiC substrates and the interfacial reaction between the SiC particles and Hastelloy were investigated by real-time observation system, X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy X-ray dispersive spectroscopy (EDS) system. The results demonstrated that the Hastelloy had a good wettability on SiC ceramic and could spontaneously infiltrate into the Ti-activated SiC preform. Moreover, intensive interfacial reaction similar to SiC/Ni system was found between the SiC particles and Hastelloy, which induced defects in the microstructure. In order to inhibit the interfacial reaction, Al 2 O 3 coating on SiC particles was adopted as a diffusion barrier, which effectively reduced the extent of the interfacial reactions.
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FIBERS AND POLYMERS
·
2014
·Vol. 15
·期 7
·1364-1368
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IF 1.113
Chen Zaina,Feng Xiaoxiao,Han Danmin,Wang Liting,Cao Weipen,Shao Linjun
Porous polyacrylonitrile (PAN) fiber mat was prepared by electrospinning PAN in N,N -dimethylformide solution with poly(methyl methacrylate) (PMMA) as pore-forming agent. Then, the porous PAN fiber mat was chemical modified by the tetraethylenepentamine to acquire aminated porous polyacrylonitrile (APPAN) fiber mat. Common aminated PAN fiber mat was also prepared for comparison. The surface morphologies of the APPAN and PAN fiber mat were characterized by scanning electron microscopy (SEM) and the corresponding specific surface areas were also measured. FT-IR/ATR spectra of the APPAN and PAN fiber mat were recorded for analysis of the surface chemical structures. The Cr(VI) absorption results demonstrated that the porous structure in the fiber could obviously increase the absorption capacity of the fiber mat.
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LANGMUIR
·
2017
·
IF 3.833
Dongfang Wang,Guilong Zhang,Linglin Zhou,Min Wang,Dongqing Cai,Zhengyan Wu
A novel magnetic nanocomposite was synthesized using graphene oxide (GO), polyethylenimine (PEI), and Fe3O4 to removal hexavalent chromium (Cr(VI)) from water and soil. Therein, GO was functionalized with plenty of −NH2 by the modification of PEI through an amidation reaction, and the resulting GO/PEI reacted with FeSO4·7H2O and NaBH4 to obtain RGO/PEI/Fe3O4 (the optimal one is designated as ORPF) through an oxidation–reduction reaction. ORPF could effectively adsorb Cr(VI) through electrostatic attraction, and the adsorbed Cr(VI) ions were partially reduced to trivalent chromium (Cr(III)) with low toxicity by RGO (π electron). Afterward, the resulting ORPF-Cr could be conveniently removed from water with a magnet, achieving the maximum Cr(VI) removal capacity of 266.6 mg/g. Importantly, ORPF, once carried by sponge particles, could efficiently remove Cr(VI) from soil, and the resulting mixture could be facilely collected with a magnet on a filter net. Besides, the leaching experiment suggested that, when supported by filter paper, ORPF was able to decrease the number of leached Cr(VI) ions and meanwhile reduce them to Cr(III). This work provides a promising approach to remediate Cr(VI)-contaminated water and soil using a nanocomposite, which has a huge number of application prospects.
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PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Weizhao Yin,Yongtao Li,Jinhua Wu,Guocai Chen,Gangbiao Jiang,Ping Li,Jingjing Gu,Hao Liang,Chuansheng Liu
A one-pot bio-iron system was established to investigate synergetic abiotic and biotic effects between iron and microorganisms on Cr(VI) removal. More diverse iron corrosion and reactive solids, such as green rusts, lepidocrocite and magnetite were found in the bio-iron system than in the Fe 0 -H 2 O system, leading to 4.3 times higher Cr(VI) removal efficiency in the bio-iron system than in the Fe 0 -H 2 O system. The cycling experiment also showed that the Cr(VI) removal capacity of Fe 0 in the bio-iron system was 12.4 times higher than that in the Fe 0 -H 2 O system. A 62 days of life-span could be achieved in the bio-iron system, while the Fe 0 -H 2 O system lost its efficacy after 30 days. Enhanced effects of extra Fe 2+ on Cr(VI) removal was observed, largely contributed to the adsorbed Fe 2+ on iron surface, which could function as an extra reductant for Cr(VI) and promote the electron transfer on the solid phase. The results also showed that the reduction of Cr(VI) by microorganisms was insignificant, indicating the adsorption/co-precipitation of Cr by iron oxides on iron surface was responsible for the overall Cr(VI) removal. Our study demonstrated that the bio-amended iron corrosion could improve the performance of Fe 0 for Cr(VI) removal from groundwater.
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