ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2018
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IF 6.653
Xinyao Shi,Wen Fang,Ni Tang,Paul N. Williams,Xuan Hu,Zhaodong Liu,Daixia Yin,Lena Q. Ma,Jun Luo
The speciation of selenium (Se) controls its fate and behavior, determining both its biological and environmental activities. However, in situ monitoring of SeIV presents a significant challenge due to its sensitivity to redox change. A novel diffusive gradients in thin films (DGT) technique containing mercapto-, amino-bifunctionalized SBA15 mesoporous silica nanoparticles was developed and evaluated in a series of laboratory and field deployment tests. The SBA-DGT exhibited a linear accumulation of SeIV (r2 > 0.997) over a 72 h deployment, with negligible accumulation of SeVI(<5%). Consistent prediction of SeIV occurred within ionic strength and pH ranges of 0.1–200 mmol L–1 and 3.6–8, respectively. Limits of detection of the SBA-DGT were 0.03 μg SeIV L–1, which is suitable for natural waters. Moreover, the properties of the bifunctionalized SBA15 enable it to be fabricated within ultrathin (0.05 mm) gel layers for use in conjunction with O2 planar optode imaging. This new sandwich sensor technology with SBA-DGT was validated by mapping the two-dimensional distribution of SeIV and oxygen simultaneously in rice rhizospheres. This study shows that SBA-DGT provides a selective measurement of SeIV in situ, demonstrating its potential for both environmental monitoring and as a research tool for improving our understanding of Se biogeochemical processes.
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Journal of CO2 Utilization
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2018
·
IF 5.503
Qian Li,Zhuxing Sun,Haiqiang Wang,Zhongbiao Wu
In this study, hollow-structured Bi decorated g-C 3 N 4 hybrids were successfully fabricated by a simple solvothermal method and applied for the first time to the photocatalytic reduction of CO 2 . Remarkably, the composites exhibited excellent CO 2 conversion efficiencies in the presence of H 2 O under visible light irradiation compared to unmodified g-C 3 N 4 , especially for the production of CH 4 . The optimum photocatalyst 30-Bi/g-C 3 N 4 presented the best production of CO and CH 4 , approximately 3 times and 9 times as high as those of unmodified g-C 3 N 4 , respectively. A series of characterizations were conducted to explore the essence behind such an enhancement; we found that enhanced light harvesting, quick separation of photoinduced carriers and more negative conduction band, due to the formation of a Schottky junction between g-C 3 N 4 and Bi metal and the solvothermal process, co-contributed for the enhanced CO 2 conversion; A more important finding was that the surprising improvement of CH 4 yield stem primarily from the introduction of the hollow-structured Bi, which enabled the accumulation of electrons on its surface exhibiting the metal-like property. The CO 2 photocatalytic conversion process was also investigated by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) spectroscopy and we found that HCO 3 − and CO 2 − were active intermediates over 30-Bi/g-C 3 N 4 and Bi doping could promote the activation of CO 2 . In summary, this work presented hollow-structured Bi decorated g-C 3 N 4 composites as new materials for energy applications, proving once more the meta-like nature of bismuth, and laying the groundwork for the utilization of Bi in CO 2 photocatalytic reduction processes.
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NEW JOURNAL OF CHEMISTRY
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2015
·Vol. 39
·期 9
·7363-7371
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IF 3.086
Wen-Yong Hu,Huan Liu,Yuan-Zhi Shao
In this study, four bi-modal core-shelled contrast agents of SiO2(FITC)@Gd2O(CO3)2·H2O with varying shell thicknesses but the same cores have been prepared via a two-step wet chemistry method. The four samples were quite close to sphericity and their averaged diameters were 127, 140, 148.7 and 174.0 nm. The composition of their shells was also examined. As the shell thickness increased, the fluorescence intensity halved but the longitudinal relaxivity remained high (28, 29, 27, 24 mM−1 s−1). The measured relaxivities of the samples were more than 5.8 times higher than the relaxivity of Gd-DTPA-BMA in a 0.55 T MR (magnetic resonance) system. The levels of cytotoxicity were tested on four cell lines (293, HeLa, HFL1, MCF-7) and the results indicated that the samples were safe. The intracellular fluorescence in HeLa cells was clearly observed using laser confocal microscopy. These results showed that this material had potential for application in MR-fluorescence bi-modal imaging.
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JOURNAL OF NON-CRYSTALLINE SOLIDS
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2015
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IF 1.766
Xijia He,Xuhui Xu,Dacheng Zhou,Cuiqiong Yan,Jianbei Qiu
The copper (Cu) atoms were incorporated into the bismuth (Bi) doped silicate glasses by the copper for sodium (Cu–Na) ion exchange method. After the ion exchange process, the Cu ions were introduced into the glass matrix with different copper valence states, namely, Cu 0 , Cu + , and Cu 2 + . Bi 3 + ions could be reduced to lower valence states of Bi containing Bi near infrared (NIR) active centers with the incorporation of the Cu ions, resulting in the enhancement of the Bi NIR luminescence intensity. During the heat treatment process, some lower valence states of Bi containing Bi NIR active centers could be oxidized, resulting in the attenuation of the NIR luminescence of Bi. Our research may extend the understanding of chemical environment modulation in Bi valence states and offer a valuable way to enhance the NIR luminescence intensity of Bi in glasses.
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TALANTA
·
2015
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IF 3.545
Mengzhen Dai,Ting Huang,Long Chao,Qingji Xie,Yueming Tan,Chao Chen,Wenhua Meng
Horseradish peroxidase (HRP)-catalyzed polymerization of l -DOPA (vs. dopamine) in the presence of H 2 O 2 (and uricase (UOx)) was exploited to immobilize mono-/bi-enzymes for hydroquinone-mediated amperometric biosensing of H 2 O 2 and uric acid (UA). The relevant polymeric biocomposites (PBCs) were prepared in phosphate buffer solution containing HRP and l -DOPA (or plus UOx) after adding H 2 O 2 . The mono-/bi-enzyme amperometric biosensors were prepared simply by casting some of the PBCs on Au-plated Au (Au plate /Au) electrodes, followed by coating with an outer-layer chitosan (CS) film for each. UV–vis spectrophotometry , scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were used for film characterization and/or process monitoring. The HRP immobilized by enzyme catalysis well preserved its bioactivity, as confirmed by UV–vis spectrophotometry . Under optimized conditions, the monoenzyme CS/HRP-poly( l -DOPA) (PD)/Au plate /Au electrode potentiostated at −0.1 V responded linearly to H 2 O 2 concentration from 0.001 to 1.25 mM with a sensitivity of 700 μA mM −1 cm −2 and a limit of detection (LOD) of 0.1 μM, and the bienzyme CS/UOx–HRP–PD/Au plate /Au electrode at −0.1 V responded linearly to UA concentration from 0.001 to 0.4 mM with a sensitivity of 349 μA mM −1 cm −2 and a LOD of 0.1 μM. The mono-/bi-enzyme biosensors based on biosynthesized PD performed better than many reported analogues and those based on similarly biosynthesized polydopamine.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2016
·
IF 3.994
Jingjing Li,Xuemei Zhang,Meng Wang,Xuejuan Li,Hongjie Mu,Aiping Wang,Wanhui Liu,Youxin Li,Zimei Wu,Kaoxiang Sun
The dual-ligand dendritic polyamidoamine-(polyethylene glycol) n -cyclic RGDyC peptide-(TAT peptide) (PP n R(T)) with various supplied molar ratios of polyethylene glycol (PEG) to polyamidoamine (PAMAM) (n = 5, 15, 30) were designed as drug-carriers for the treatment of neovascular diseases; their targeting and penetrating effects were subsequently evaluated. 1 H NMR demonstrated PP n R(T) was successfully synthesized. Compared with the unmodified PAMAM, in vitro cytotoxicity of PP n R(T) to αvβ3 negative cells (αvβ3-) was significantly reduced, whereas the lethality to pathologic neovascular endothelial cells (αvβ3+) was efficiently increased compared to PP n . Compared to PP 5 R(T) and PP 15 R(T), PP 30 R(T) exhibited the most selective and efficient cellular uptake by human umbilical vein endothelial cells (HUVECs, αvβ3+). Membrane interaction study indicated the cellular uptake process of PP 30 R(T) of HUVECs mainly involved specific RGD-αvβ3 recognition as well as electrostatic interactions. Intracellular localization results confirmed PP 30 R(T) was distributed in the cytoplasm in HUVECs. 3D tumor spheroids penetration studies demonstrated that PP 30 R(T) penetrated the A549 cells to reach the depths of the avascular tumor spheroids. In vivo imaging further demonstrated that PP 30 R(T) achieved profoundly improved distribution in tumor tissues where angiogenesis existed. Therefore, the bi-functional dendrimer PP 30 R(T) displayed great potential as a nano-carrier for targeted drug delivery both in vitro and in vivo , and had broad prospects as nanocarriers for the targeted treatment of neovascular diseases.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
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IF 9.446
Danjun Mao,Shanshan Ding,Lingjun Meng,Yuxuan Dai,Cheng Sun,Shaogui Yang,Huan He
The novel Bi-rich Bi 4 O 5 Br 2 with tunable morphologies of two-dimentional (2D) nanosheets (NSs), three-dimentional (3D) monodisperse layered microspheres (LMs) and hollow spheres (HSs) have been successfully synthesized via an ionic liquid-in-water (IL/W) microemulsion method. Surfactant TX-100 served as the stabilizer of the IL/W microemulsion, and its concentration significantly influenced the morphology and size of the resulting Bi 4 O 5 Br 2 crystal. Possible formation mechanisms have also been discussed. UV–vis diffuse-reflectance spectra and Density function theory (DFT) calculations indicated that Bi 4 O 5 Br 2 possessed stronger visible light adsorption and more negative conduction band minimum (CBM), which is beneficial to effectively activate molecular oxygen to produce O 2 − . The photocatalytic activity of Bi-rich Bi 4 O 5 Br 2 with varied shapes was investigated and compared with BiOBr for the removal of fungicide o-phenylphenol (OPP) and antibacterial agent norfloxacin (NOR) and tetracycline hydrochloride (TC) under visible light irradiation. The as-prepared Bi 4 O 5 Br 2 HSs and LMs possess higher photocatalytic efficiency than Bi 4 O 5 Br 2 and BiOBr NSs, which is attributed to the hollow/layered spherical structures and Bi-rich strategies. The O 2 − and h + are identified to be the major photoactive species during the photo-degradation process by scavenger experiments and EPR methods. This study is expected to provide a stepping stone to purposively design and explore other novel hollow structures with controllable morphology and enhanced photocatalytic activity.
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ELECTROCHIMICA ACTA
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2017
·
IF 4.798
Wen Wu,Zhenghua Tang,Kai Wang,Zhen Liu,Ligui Li,Shaowei Chen
Peptide driven metallic nanomaterials fabrication under mild conditions has become a significant research thrust recently, thanks to its capability to generate multifunctional materials with tunable electronic and catalytic properties. Herein, peptide Z1 is employed to fabricate a series of AuPt alloyed nanoparticles with different Au-to-Pt ratios. The morphology is examined by electron microscopic techniques, and well-defined peanut-shape is observed for Au 33 Pt 67 while spherical particles are obtained for the other samples. The AuPt alloys demonstrate effective electrocatalytic activity toward both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) and Au 33 Pt 67 exhibits the best bifunctional electrocatalytic performance. Its ORR activity is superior than commercial Pt/C in alkaline media, verified by the positive onset potential (+1.02 V vs. RHE) and large diffusion-limited current density, while its HER activity is comparable with Pt/C, evidenced by the small overpotential at 10 mA cm −2 (−171 mV vs. RHE) and low Tafel slope. Moreover, Au 33 Pt 67 exhibits markedly higher long-term durability than Pt/C for both ORR and HER. The excellent activity and stability for ORR and HER are ascribed to Au alloying Pt induced synergistic effects. The results highlight the advantages of using peptide to fabricate bi-functional or multiple functional electrocatalysts with desirable activity and robust stability.
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Water
·
2024
·Vol. 16
·期 17
·2389
·
IF 3
Yuli Chen,Dechong Ma,Guowen He,Sai Pan
In this study, fusiform bismuth (Bi) was synthesized, and its photocatalytic performance, degradation mechanism, and pathways for removing rhodamine B (RhB) at different pH levels were investigated. Additionally, the morphologies, structural characteristics, surface electronic states, optical properties, active species, and potential degradation pathways of RhB over the fusiform Bi were analyzed. The comparison of the results before and after RhB degradation using the fusiform Bi revealed the formation of a Bi/BiOCl heterojunction photocatalyst. At pH 2.0, 3.0, 5.0, 7.0, and 9.0, the heterojunction exhibited excellent photocatalytic activity, with RhB removal efficiencies of ~97%, 96.7%, 72.6%, 53.5%, and 27.6%, respectively. Moreover, total organic carbon and chemical oxygen demand analyses were performed to evaluate the mineralization rates of RhB with the fusiform Bi at pH 3.0 and 7.0. Furthermore, the effects of catalyst content, initial RhB concentration, light source distance, inorganic anions, and reactant temperature on the photocatalytic performance of the fusiform Bi were investigated. Additionally, the types of active species and potential photocatalytic mechanisms for RhB degradation over the fusiform Bi at different pH levels (3.0 and 7.0) were elucidated. The appropriate degradation pathways were identified via liquid chromatography–mass spectrometry at pH 3.0 and 7.0.
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JOURNAL OF RARE EARTHS
·
2024
·
IF 5.2
Rui Shi,Yan’an Li,Jiutao Gao,Ziyang Chen,Xin Zhang,Shanlin Zhang,Zaheer Ud Din Babar,Chengxin Li
This study focused on meeting the stringent stability requirements of tubular segmented-in-series solid oxide fuel cells (SOFCs) in reducing and oxidizing atmospheres. To address this challenge, a bi-layer perovskite ceramic interconnect was designed by controlling the oxygen partial pressure, because of the strong correlation between the conductivity of strontium-doped lanthanum titanate (LST) and the oxygen partial pressure. The LST powder was prepared using solid-phase and sol-gel methods, and their influence on particle size and sintering behavior was compared. LST/lanthanum strontium manganite (LSM) bi-layer ceramic interconnects with varying thicknesses were fabricated through screen printing and co-sintering. The results demonstrate favorable interfacial bonding and excellent chemical compatibility between the ceramic layers. The conductivity of the bi-layer interconnect exhibits a temperature-dependent behavior, peaking at 550 °C. Simulation calculations and research findings validate that the conductivity of the bi-layer interconnect is determined by the thickness of the LSM layer and the oxygen partial pressure at the interconnect interface. Optimal conductivity is achieved with a bi-layer interconnect consisting of approximately 15 μm of LST and 4 μm of LSM. This can be attributed to the efficient regulation of oxygen partial pressure at the interface, effectively mitigating LSM decomposition caused by low oxygen partial pressure and the subsequent reduction in conductivity. These results provide valuable fundamental data and methodology for the development of high-performance interconnects for tubular segmented-in-series SOFCs.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Xiaolin Shen,Zhiliang Zhu,Xiaochang Liu,Renlu Qiao,Hua Zhang,Yanling Qiu
Reutilization of spent adsorbent by converting the adsorbed organic pollutants into carbon matrix has attracted more attention in recent years, which delivers a greener way for the preparation of catalysis and environment remediation. In this work, CuBi 2 O 4 after adsorption of pollutant sulfamethazine was further transformed to a photocatalyst CBO-WC500 with high catalytic efficiency for degradation of typical pharmaceuticals. The XAFS analysis proved that Cu-C chemical bond was constructed during the preparation process. The obtained CBO-WC500 was applied to remove sulfamethoxazole (SMX) through photocatalytic Fenton-like reaction, and removal efficiency reached 88.9 % after 60 minutes with the initial 5 mg•L −1 SMX and 0.2 g•L −1 catalyst in peroxymonosulfate (PMS) system. The results showed that the introduction of carbon stem from waste improved separation of photo-generated carriers and electron transfer capability, thus more photo-induced electrons could participate in reaction with PMS. Moreover, Cu(I) and Cu(II) in CBO-WC500 with Cu-Bi-spinel structure played a vital role in PMS activation. Led by electron transportation, reactive species ( 1 O 2 , •OH, SO 4 •- ) originated from PMS contributed to degradation of SMX, and degradation pathway of target pollutant was proposed based on analysis of intermediates. Removal efficiency of CBO-WC500 for SMX kept stable after several cycles’ utilization, and it also showed decent eliminating performance of mixed pollutants in different water matrix. This study has provided a potential way for resource reuse of adsorbed pollutant and realizing reutilization of spent adsorbent as photocatalyst with higher efficiency.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Ming Zhang,Ting An,Xiuduo Song,Fengqi Zhao,Ergang Yao,Yongqiang Xue,Ying Wang,Xueli Chen,Zhifeng Yuan,Libai Xiao
In order to deal with the long-standing contradiction between safety and performance for propellent combustion catalyst, the TKX-50-M (M=Pb, Bi and Cu) were designed, synthesized and characterized. The density, thermal decomposition, mechanical sensitivity and energy performance of the prepared TKX-50-M were studied systemically. By taking NTO-Pb as the benchmark, the TKX-50-M exhibited much better energetic and safety properties. Besides, the combination of TKX-50-Pb, TKX-50-Cu and carbon black is conductive to the combustion of HMX-CMDB propellant. The burning rate of HMX-CMDB propellant increases from 16.80 to 21.28 mm s −1 at 20 MPa, and the pressure index reduces from 0.87 to 0.39 in the pressure range of 10–20 MPa. The catalytic mechanism of TKX-50-M were explored according to the results of combustion wave structure, flame image and characteristics of burning out surface. The catalytic effect of TKX-50-Pb is mainly reflected in the gas phase region, and the introduction of TKX-50-Cu and carbon black shows a significant synergistic catalytic effect. The results of this study not only help to explore insensitive high-energy combustion catalyst, but also helps to improve the combustion, energy and safety performance of CMDB propellants.
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