ENVIRONMENTAL POLLUTION
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2019
·
IF 5.714
Yi Shen,Chao Zhu,Baoliang Chen
To improve catalytic performance and stability of Ag nanoparticles (Ag NPs), a facile ultrasonication-assisted chemical reduction method was developed to fabricate reduced graphene oxide (rGO) aerogels loaded with 1–3 nm Ag NPs under the normal temperature and pressure. The ultrasonication facilitated the dispersion of Ag(I) in the form of silver ammonia and anchored onto GO nanosheets . Ag(I) and GO were simultaneously reduced to Ag(0) immobilizing onto 3D rGO hydrogels within the heterogeneous liquid phase, and ultimately formed 3D rGO-Ag NPs aerogels . The 3D rGO-Ag NPs aerogels displayed superb catalytic performance for the reduction of nitrobenzene (NB), 1,3-dinitrobenzene (DNB) and 4-nitrophenol (NP) into aniline, 1,3-diaminobenzene and 4-aminophenol, respectively. The individual reduction rate K obs for NB, DNB and NP were 0.168 h −1 , 0.109 h −1 and 0.092 h −1 , which were much higher than those of other Ag NPs-based materials. Moreover, the immobilization of 1–3 nm Ag NPs in 3D rGO-Ag NPs was stable during the whole reduction reaction without aggregation and leaching. The high stability of Ag NPs in 3D rGO-Ag NPs and superb performance on catalytic reduction of nitroaromatic compounds (NACs) could be concluded into ultrasonication influence in the preparation procedure and synergistic effect of Ag NPs and 3D rGO in the catalytic reduction process. The simple ultrasonication-assisted chemical reduction approach provided a scaled-up application prospect in catalytic reduction of NACs by metal nanoparticle catalysts.
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高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2019
·
IF 3.973
Qingmiao Zhang,Yilei Wang,Wenkun Zhang,Michael E. Hickey,Zhuangsheng Lin,Qin Tu,Jinyi Wang
Nanofibrous membranes which exhibit bacteriostatic functions are a good strategy to prevent microorganisms from adhering to the surface of biomaterials. Here, we report the synthesis of such a nanofibrous membrane which can be applied to biological coatings to reduce bacteriostatic functionality. Ascorbic acid was utilized to reduced chloroauric acid to gold nanoparticles (AuNPs). Dopamine was then polymerized upon AuNP surfaces by ultrasound-assistance, to synthesize core-shell structured polydopamine-coated AuNPs (Au@PDA NPs). The Au@PDA NPs were then mixed with polylactic acid (PLA) for electrospinning into cylindrical nanofibers (136.6 nm diameter). PLA-Au@PDA nanofibrous membranes were finally immersed in silver nitrate for in situ reduction into a silver nanoparticle (AgNP) coating to yield PLA-Au@PDA@Ag nanofibers. The PLA-Au@PDA@Ag nanofibers were characterized based on field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle analyses. The antibacterial properties of the PLA-Au@PDA@Ag nanofibers were examined based on the optical density absorbance of bacterial cell suspensions, traditional colony plate counts, zone inhibition analyses, and field-emission scanning electron microscopy. Escherichia coli and Staphylococcus aureaus respectively served as Gram negative and positive bacterial models of industrial relevance. The data conclusively illustrates the antimicrobial and biomedical applications of PLA-Au@PDA@Ag nanofibers.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Zehao Wang,Xuejun Xu,Zhichun Si,Liping Liu,Yuxiang Liu,Yonghong He,Rui Ran,Duan Weng
MoS 2 /Ag 3 PO 4 heterojunction photocatalysts have attracted great attention in dye degradation and water oxidation, in which Z-scheme plays a critical role in the catalytic performance as a result of energy band structure alignment between MoS 2 and Ag 3 PO 4 . Creating metal sites at composite interfaces as recombination centers of photo-generated electrons from conduction band (CB) of Ag 3 PO 4 and holes from valence band (VB) of MoS 2 is an effective strategy to enhance the charge separation efficiency and photocatalytic performance. Strong coupled MoS 2 /Ag dots/Ag 3 PO 4 ternary heterojunction photocatalysts were fabricated by one-pot precipitation method, in which highly dispersed Ag dots are located at the MoS 2 /Ag 3 PO 4 interfaces and MoS 2 is bonded with PO 4 3- in the form of Mo-O-P. The fabricated MoS 2 /Ag dots/Ag 3 PO 4 photocatalyst presents a 2.8-fold enhancement of photocatalytic activity of water oxidation compared to that of pristine Ag 3 PO 4 , which is achieved for the first time. The great enhancement of photocatalytic performance can be ascribed to the improved Z scheme mechanism with strongly coupled MoS 2 /Ag dots/Ag 3 PO 4 ternary interfaces, in which highly dispersed Ag dots serve as efficient recombination centers resulting in the improved separation of photo-generated holes and electrons of Ag 3 PO 4 as well as photocatalytic activity of oxygen evolution.
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ACS Omega
·
2022
·
IF 4.132
Xianglong Li,Yongna Zhang,Weicai Kong,Jing Zhou,Teng Hou,Xianggui Zhang,Lele Zhou,Mingbo Sun,Shu Liu,Bin Yang
In this research, centrifugally spun ultrafine composite starch/polyvinyl alcohol (ST/PVA) fibers with high water stability were prepared by cross-linking with a mixture of glutaraldehyde and formic acid in the form of vapor phase. The effect of cross-linking temperature combined with time on the water stability, crystal structure, and thermal properties of fibers was investigated to obtain the optimum parameters. On this basis, we further prepared Ag-loaded ST/PVA fibers with different contents of nano silver. The structure and properties of Ag-loaded fibers, which cross-linked under the optimum parameters, were analyzed. As a result, the Ag-loaded fibers exhibited excellent water stability and mechanical properties and possessed inhibition zone diameters of 3 and 2 mm to Escherichia coli and Staphylococcus. aureus, respectively. The antibacterial property of the Ag-loaded ST/PVA fibers provided a new route for developing less costly antibacterial fiber materials in the future.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
·
IF 9.446
Qingqing Lang,Yaohan Chen,Tianlong Huang,Lining Yang,Shuxian Zhong,Lanju Wu,Jianrong Chen,Song Bai
The integration of plasmonic metal with wide-bandgap semiconductor is a promising approach to utilize the visible light without compromise of the redox ability of photogenerated charge carriers. However, a larger work function of metal than that of semiconductor is indispensable to enable the injection of hot electrons from plasmonic metal to semiconductor. In this paper, we demonstrated that reduced graphene oxide (rGO) nanosheets as conductive “bridge” can breakthrough the restriction and transfer hot electrons from Ag of smaller work function to TiO 2 of larger work function. In the design, both of the Ag nanocubes and TiO 2 nanosheets are co-deposited on the surface of rGO nanosheets to form Ag-rGO-TiO 2 structure, which was characterized by XRD, TEM, Raman and XPS spectra. On one hand, the Ag-rGO interface facilitates the transfer of hot electrons from Ag to rGO through conductor–conductor contact. On the other hand, the new formed Schottky junction on the rGO-TiO 2 interface further pumps the transferred electrons to the surface of TiO 2 for photocatalytic reduction reaction resulted from the larger work function of rGO than that of TiO 2 . Enabled by this unique design, the hydrogen production activity achieved under visible light irradiation is dramatically enhanced in comparison with that of Ag-TiO 2 counterpart with the direct contact between the same Ag nanocubes and TiO 2 nanosheets. This work represents a step toward the rational interfacial design of plasmonic metal-semiconductor hybrid structures for broad-spectrum photocatalysis.
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高影响因子
MATERIALS RESEARCH BULLETIN
·
2019
·
IF 3.355
Sefiu Abolaji Rasaki,Chunlei Zhao,Rui Wang,Jiacheng Wang,Heng Jiang,Minghui Yang
In this work, Ag/ZnO nanorods are prepared via simple and cost-saving liquid precipitation citrate reduction process (LPCR). The system shows appreciable catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) wherein NaBH 4 is used as electron sacrificer at ambience. It is found out that ZnO nanorods can effectively prevent Ag NPs agglomeration; a problem normally reduces active sites density. The coupling effect between the Ag NPs and ZnO greatly enhances electron transfer rate. This gives rise to high reduction rate constant ( k app ) of ˜3.97 × 10 −3 s −1 for the catalytic reduction of 4-NP. The result is about 1.9times better than that of Ag NPs (2.07 × 10 −3 s −1 ). The k app is well fitted into pseudo-first order kinetics with high correlation coefficient (R 2 ) of about 0.994, indicating chemisorptive reduction process. The remarkable performance obtained here is attributed to strong coupling effect between Ag NPs and ZnO nanorods derived from LPCR synthesis method.
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Materials Research Express
·
2022
·Vol. 9
·期 1
·016303
·
IF 2.025
PeiYuan Fan,WenHua Zhang,Xianglei Yu,GuoYou Gan
Attaining low-temperature sintering and high electrical conductivity is vital in the field of flexible electronics. Inks with silver oxalate as the precursor have recently received significant attention in this field; however, the high sintering temperature and long sintering time limit commercial applicability. High sintering temperature can shorten the sintering time but lead to porous and uneven film morphology; thus, reducing the conductivity. On the other hand, low sintering temperature prolongs the sintering time; thus, reducing the production efficiency. To solve the abovementioned problems, a silver composite conductive ink modified by polyvinylpyrrolidone (PVP) was prepared in this study. The ink used silver oxalate as the precursor, methanol and acetone as the solvent, and 1, 2-diaminopropane as the complexing agent, and could reduce the sintering temperature and time to 160 °C and 20 min, respectively. After sintering, the silver film showed good electrical conductivity, and low resistivity (4.56 μΩ·cm). Furthermore, the impact of sintering temperature on the surface morphology and electrical conductivity were also studied, and the results showed that PVP had a positive influence on the nucleation of silver and the microstructure of the sintered silver film.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2022
·Vol. 106
·期 2
·444-454
·
IF 2.606
Zhang Ji,Mu Chengfa,Shen Tao,Qi Gengxin
Different micro-structured SnO 2 powders were synthesized by hydrothermal and chemical co-precipitation methods. The influence of milling process and sintering parameters on the physical properties of Ag/SnO 2 electrical contact materials was investigated. The microstructure and physical properties of Ag/SnO 2 electrical contact materials were characterized by X-ray Diffraction, Scanning Electron Microscopy and Conductivity analyzer. The results showed that spherical SnO 2 (s) powders with a diameter about 2 μm were synthesized. With increased milling time, there was a slight decrease in the average sizes of Ag/SnO 2 (s) powders, but no significant difference. The optimal density of 9.545 g∙cm −3 and resistivity of 2.67 μΩ∙cm of Ag/SnO 2 (s) electrical contact materials were obtained after sintering at 860 °C for 6 h in air atmosphere. The promotion of sintering densification and improvement of physical properties of Ag/SnO 2 (s) contact may be due to the combined effects of mechanical activation energy and higher sintering temperature. Using the finite element method, simulation models were developed to interpret the effects of different micro-structured SnO 2 powders on the physical properties of Ag/SnO 2 materials.
Graphical abstract
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高影响因子
BIOELECTROCHEMISTRY
·
2022
·
IF 5.76
Qian Liu,Huawei Shen,Baiying Li,Juan Cai,Yang Peng,Zhi Weng,Hongyan Yu,Guoming Xie,Wenli Feng
Currently, developing an effective and easy-to-operate signal amplification assay to detect the trace-amount miRNAs in serum remains a significant challenge. Herein, an ultrasensitive CeO 2 @Ag hybrid nanoflower (CeO 2 @Ag HNF)-labeled electrochemical biosensor was developed for sensing miRNA, based on a target-feedback rolling-cleavage (TFRC) signal amplifier. CeO 2 @Ag HNFs possessing a unique three-dimensional layered structure were synthesized without any complex reaction conditions, such as heating and vacuum. The bimetallic nanoflowers provided a large surface area and excellent CAT-like activity, thereby enhancing electrochemical performance. Based on the principle of branched catalytic hairpin assembly, target miRNA could continuously trigger the assembly of branched junctions with ends composed of DNAzyme. The activated DNAzyme was able to cleave the hairpin substrate efficiently and release to capture more CeO 2 @Ag HNFs label. The process combining target-driven branched catalytic hairpin assembly and DNAzyme-assisted rolling cleavage were defined as TFRC signal amplification. This sensitive electrochemical biosensor exhibited good linear relationship of 1 fM − 1 nM with a detection limit down to 0.89 fM. The proposed method is expected to have a promising application in the miRNA-associated fundamental research and clinical diagnosis.
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Analytical Methods
·
2022
·Vol. 14
·期 10
·1041-1050
·
IF 3.532
Shiqiang Wang,Bing Sun,Huiyun Jiang,Yan Jin,Junjie Feng,Fei An,Haozhi Wang,Wei Xu
Surface enhanced Raman spectroscopy (SERS) has emerged as a promising tool for the rapid and ultrasensitive recognition of trace amounts of environmental pollutants. Hierarchical SERS substrates usually show superior performance to single-component substrates but require complicated preparation protocols. Herein, a facile, robust and low-cost route for the fabrication of hierarchical SERS substrates has been reported, in which no complicated laborious protocols or sophisticated equipment is needed. In the hierarchical SERS substrate, Au nanorods were distributed onto the network of Ag nanowires through evaporation induced self-assembly. The density of the Au nanorods and Ag nanowires could be easily tailored by tuning the number of droplets of gold nanorod solution and the concentration of silver nanowire solution. The nanogaps formed between Au nanorods and Ag nanowires were able to induce a rich enhanced electromagnetic field area via localized surface plasmon resonances and surface plasmon polaritons to achieve amplification of the Raman signal. The as-prepared substrate showed high uniformity and was capable of identifying 10−12 M rhodamine 6G, 10−10 M thiram and 10−10 M crystal violet, with correlation coefficients (R2) all higher than 0.98. This approach can be employed for the detection of trace dyes, pesticides or other environmental pollutants with high sensitivity and uniformity.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 55
·期 2
·701-712
·
IF 3.442
Yang Wangyang,Shen Honglie,Min Huihua,Ge Jiawei
In recent years, Ti 3+ self-doped TiO 2 (B-TiO 2 ) exhibits great potential as a photocatalyst. In this work, Ti vapor-assisted annealing is first demonstrated for Ti 3+ doping and improving the visible absorption of TiO 2 . TEM results exhibit the formation of disordered layer, indicating the successful fabricating of B-TiO 2 . The absorption increase in TiO 2 caused by Ti vapor annealing reaches nearly 50% in the visible wavelength range. Benefiting from the absorption increase, the photocatalytic performance of TiO 2 after Ti vapor annealing increases by 60–70%. Surface modification of Ag onto B-TiO 2 is also carried out to further improve its optical property. Ag-modified Ti 3+ self-doped TiO 2 (B-TiO 2 @Ag) exhibits great visible photodegradation behavior to RhB. The RhB degradation rate reaches 97.76% after 60 min of visible light irradiation. Electrochemical performance tests demonstrate that as-prepared TiO 2 @Ag has lower resistance than W-TiO 2 . The results indicate that B-TiO 2 @Ag has great potential in solar photocatalytic degradation of pollutant.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Huarong Liao,Miaomiao Li,Yuxiang Wang,Guan Wang,Liujun Yang,Junxia Shao,Cheng Zhang,Hua Li,Jianmei Lu
Refining the visible light absorption and optimizing the separation of photogenerated electron-hole pairs are pivotal in enhancing the photocatalytic activity of composites. A novel Z-scheme plasma photocatalyst, Ag/Ag 3 PO 4 /In-MOF (A/AP/In), was developed in this study. Experimental results demonstrated that A/AP/In exhibited the highest photocatalytic activity for BPA among all samples tested, achieving complete degradation of 50 ppm BPA within 30 min, as well as its apparent degradation rate was about 11 times higher than that of pure Ag 3 PO 4 and 4 times higher than that of pure In-MOF. The enhanced photocatalytic activity can be mainly attributed to the existence of Z-type heterojunctions and the surface plasmon resonance (SPR) effect induced by Ag nanoparticles , which facilitate efficient migration and separation of photogenerated carriers. Meanwhile, the incorporation of Ag nanoparticles enhances visible light absorption and protects Ag 3 PO 4 from photocorrosion in the composites. Moreover, A/AP/In maintains the large specific surface area of In-MOF and provides abundant reactive active sites. In addition, the photocatalytic performance of A/AP/In was above 90 % after five consecutive cycles confirming its good stability. Overall, this study proposes a novel approach for constructing bifunctional composites with efficient adsorption/catalytic degradation.
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