JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2020
·
IF 2.369
Xiangmeng Chen,Xingchuan Yang,Yong Xiang,Li Xu,Guoji Liu
Humic acid-derived resin (named “RFH”) is employed for efficiently recovering gold from acidic aqueous solutions. The selectivity and effects of pH, contact time, initial concentration, and temperature on Au(III) adsorption by RFH have been studied. The RFH resin exhibited remarkable selectivity for gold ions over other metal ions and very high adsorption capacity for Au(III), up to 920 mg·g–1. The gold adsorption nicely conforms to the Freundlich isotherm model, and the removal of Au(III) from the aqueous solution by RFH resin follows pseudo-second-order kinetics. The RFH resin before and after adsorption was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), which provided evidence for gold adsorption mechanism of RFH. The results showed that Au(III) was adsorbed on RFH, then reduced to elemental gold, and deposited on the adsorbent in the form of the element gold. We summarize the process as an adsorption–reduction–deposition mechanism. This paper provide a new way for gold recovery from aqueous acidic solutions.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
·
IF 7.489
Fang Li,Haiping Zhou,Jiajie Fan,Quanjun Xiang
Amine-functionalized graphitic carbon nitride (g-C 3 N 4 ) decorated with Au nanoparticles (CN/Au) was prepared by N 2 plasma treatment of g-C 3 N 4 powders impregnated with HAuCl 4 ·3H 2 O. Well-dispersed Au nanoparticles with a small particle size were deposited on g-C 3 N 4 nanosheets. In addition, the amino group was introduced into the CN/Au system. Without the addition of cocatalyst and sacrificial agent, CN/Au exhibited enhanced photocatalytic activity for CO 2 reduction under visible-light irradiation. CO and CH 4 evolution rates of CN/Au reached 28.3 and 1.3 μmol·h −1 ·g −1 , which were 7.6 and 2.6 times higher than those of pristine g-C 3 N 4 (CN-0), respectively. The enhanced activity can be explained by these factors. (1) The introduced amino group improved the adsorption capacity of CN/Au for CO 2 ; (2) the hot electrons generated by Au nanoparticles activated the surrounding electrons through energy transfer and caused local temperature to rise, increasing the efficiency of the photoreduction reaction of CO 2 ; (3) the Schottky junction between Au and g-C 3 N 4 promoted the migration of electrons from g-C 3 N 4 to Au nanoparticles, suppressing the recombination of the carriers. Time-of-flight secondary ion mass spectrometry confirmed the introduction of amino groups, and solid-state 13 C nuclear magnetic resonance spectra provided a support for inferring the position of the amino group.
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ACS Applied Nano Materials
·
2020
·
IF 0
Xinyuan Bi,Yuqing Gu,Jian Ye
Single-molecule (SM) detection in surface-enhanced Raman spectroscopy (SERS) demonstrates ultrahigh sensitivity and boosts wide applications. The bianalyte SERS (BiASERS) technique largely improves the accuracy and reliability of SM SERS detection over the monoanalyte approach by avoiding the use of ultralow-concentration samples and induced inaccuracy and very limited events. Herein, dual-type single-nanoparticle (SNP) SERS detection, an adapted version of the bianalyte SM technique, was developed for the first time with two types of ultrabright gap-enhanced resonance Raman tags (GERRTs) with embedded near-infrared resonant fluorescent molecules, showing concentration- and acquisition time-dependent behaviors and the SNP sensitivity in both aqueous and dry states. Additionally, a correlative Raman imaging and scanning electron (RISE) microscopy confirms the SNP events of GERRTs on the substrate. Therefore, we expand the feasible application scenarios of the BiASERS technique from merely SM to SNP detection and more importantly demonstrate the effectiveness of the pure statistical model of BiASERS with the undoubted experimental examinations. Dual-type SNP detection of GERRTs may open new opportunities for development of ultrasensitive nanotags for reliable localized and quantitative detection in biological environments.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Xiaojie Shi,Huimin Liu,Mei Zhang,Fengzhen Yang,Jiansen Li,Yemin Guo,Xia Sun
An ultrasensitive aptasensor based on luminol-hydrogen peroxide (H 2 O 2 ) electrochemiluminescence (ECL) system was proposed for determination of profenofos. AuNPs decorated with MWCNTs ( [email protected] ) were used to provide a favorable microenvironment for luminol loading and improve the ECL signal due to their good biological activity, excellent electrical conductivity and high specific surface area. Gold and silver core-shell nanoparticles ( [email protected] ) could act as effective catalyzer to accelerate H 2 O 2 decomposition to produce various intermediate reactive oxygen species for signal amplification and thus increased the ECL signal again. Under optimal conditions, the proposed ECL aptasensor obtained an extremely low detection limit of 5.32 fg/mL (S/N = 3) with a good detection range from 100 fg/mL to 1 μg/mL. Moreover, the proposed aptasensor had excellent specificity, outstanding repeatability and favorable stability. Finally, the proposed ECL aptasensor was used for the detection of profenofos in real samples and the recoveries ranged from 94% to 102%. This strategy could provide a good reference for developing effective aptasensors for detection of other small molecules and toxins.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2021
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IF 4.098
Wenxian Wei,Dan Yu,Yu Du,Yicheng Ding,Qingli Huang
Au-Ag alloy nanoparticles (NPs) with controllable size and composition were synthesized by a facile, one-pot hydrothermal method. Various characterization techniques including TEM, UV–vis, EDX, HAADF-STEM and XPS were used to discuss the influencing factors for the size and composition of Au-Ag alloy NPs. It is obvious that the size and composition of Au-Ag alloy NPs could be adjusted by the experimental parameters. Catalytic and SERS performance of the Au-Ag alloy NPs were further investigated. Ideal catalytic and SERS performance could be also obtained via optimizing the size and composition of Au-Ag alloy. This work is of importance in theory research and practical application of the noble metal nanocomposites.
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SENSORS
·
2019
·Vol. 19
·期 22
·5055
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IF 3.031
Min Jiang,Peng Sun,Jie Zhao,Lihua Huo,Guofeng Cui
Flexible physiological medical devices have gradually spread to the lives of people, especially the elderly. Here, a flexible integrated sensor based on Au nanoparticle modified copper hydroxide nanograss arrays on flexible carbon fiber cloth ([email protected](OH)2/CFC) is fabricated by a facile electrochemical method. The sensor possesses ultrahigh sensitivity of 7.35 mA mM−1cm−2in the linear concentration range of 0.10 to 3.30 mM and an ultralow detection limit down to 26.97 nM. The fantastic sensing properties can be ascribed to the collective effect of the superior electrochemical catalytic activity of nanograss arrays with dramatically enhanced electrochemically active surface area as well as mass transfer ability when modified with Au and intimate contact between the active material ([email protected](OH)2) and current collector (CFC), concurrently supplying good conductivity for electron/ion transport during glucose biosensing. Furthermore, the device also exhibits excellent anti-interference and stability for glucose detection. Owing to the distinguished performances, the novel sensor shows extreme reliability for practical glucose testing in human serum and juice samples. Significantly, these unique properties and the soft structure of silk fabric can provide a promising structure design for a flexible micro-device and a great potential material candidate of electrochemical glucose sensor.Keywords:Cu(OH)2nanograss;Au nanoparticles;glucose detection;flexible electrochemical biosensor
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ChemCatChem
·
2019
·Vol. 11
·期 24
·6372-6383
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IF 4.495
Wenhua Ye,Jisong Hu,Xiaofeng Hu,Wenhua Zhang,Xinguo Ma,Huihu Wang
Graphical Photocatalysis : The traditional p–n junction charges transfer mode at the interface of CuInS 2 /g-C 3 N 4 can be switched to Z-scheme mode in CuInS 2 /Au/g-C 3 N 4 heterostructure through Au integration by weakening the built-in electric field and improving the interfacial bonding. Two dimensional (2D) heterojunction based on g-C 3 N 4 and CuInS 2 (CIS) nanosheets has been successfully constructed with the assistance of biomolecules L-cysteine. We demonstrated that a typical p–n junction charges transfer mode of CIS/PCN (protonated g-C 3 N 4 ) can be switched to Z-scheme transfer mode through the integration of Au by weakening the role of built-in electric field. The morphology of CIS/Au/PCN can be well adjusted through the formation of Au−S covalent bond and the electrostatic adsorption between Au and PCN during the hydrothermal process. Furthermore, the intimate interface contact inside CIS/Au/PCN heterojunction was indeed constructed, which may promote the charges separation and transfer process at the interface as evidenced by ESR spectra and time-resolved PL spectra. Under visible light illumination, the CIS/Au/PCN exhibited an enhanced CO (19.46 μmol/g) and CH 4 (1.18 μmol/g) yield in CO 2 reduction, which was about 5.04 times and 2.03 times higher than pure PCN. The composite heterojunction also showed excellent photocatalytic activity for tetracycline degradation with a 87 % degradation efficiency in 1 hour, which was 2.07 times higher than pure PCN. The experimental and theoretical calculation results demonstrated that an all-solid-state Z-scheme heterojunction was formed in the CIS/Au/PCN system, which was different from the typical p–n junction charges transfer mechanism in CIS/PCN.
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Journal of Materials Chemistry B
·
2019
·Vol. 7
·期 40
·6202-6209
·
IF 5.047
Zhiqiang Wang,Xiuzhen Huang,Sheng Jin,Hongwei Wang,Lin Yuan,John L. Brash
The continuing emergence of antibiotic-resistant bacteria due to the excessive use of antibiotics has produced a strong demand for novel strategies and new materials that do not lead to bacterial resistance. In the present work silicon nanowire arrays modified with gold–silver alloy nanoparticles (SN-Au/Ag) was investigated as a photo-induced antibacterial material. It was shown that SN-Au/Ag can kill bacteria with high efficiency under sunlight in times of the order of a few minutes, and this is achieved through synergism between photothermal and photocatalytic effects. It appears that the combined effect of heat and reactive oxygen species (ROS) causes bacteria killing through damage to the cell membrane and leakage of cytoplasm contents. Both gold and silver in the alloy nanoparticles are required for the observed bactericidal action. Moreover, the SN-Au/Ag material can be “recycled” without loss of bactericidal activity. It is concluded that the silicon nanowire arrays modified with gold–silver alloy nanoparticles developed in this work has promise as an antibacterial nanomaterial for the development of novel antibiotics.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yue Chang,Ying Xuan,Huiying Quan,Hang Zhang,Shuangxi Liu,Zhengcao Li,Kai Yu,Jiangli Cao
As one of the most promising photocatalysts for hydrogen production from water splitting, conventional TiO 2 materials suffer from the low quantum yield and light absorption efficiency. The present study provided a strategy to improve efficiency of TiO 2 -based photocatalysts for hydrogen production from water splitting based on an interesting structure-property relationship. The hydrogen treated Au/TiO 2 photocatalysts with three-dimensionally ordered macroporous (3DOM) structure were successfully synthesized and well characterized through various methods. The 3DOM-structure and Au modification can promote the hydrogenation of TiO 2 . The light absorption can be improved by slow photon effect of the 3DOM structure. And, in the meanwhile, the hydrogenation as well as Au modification can improve the photogenerated carrier separation. In addition, to understand how hydrogenation and Au modification promote electron migration and decrease carrier recombination, the electric band structure for hydrogen treated Au/3DOM-TiO 2 was well studied and we found the local electron field enhancement, surface band bending and the generation of mid-gap state contributed most of enhancement.
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GREEN CHEMISTRY
·
2019
·Vol. 21
·期 23
·6318-6325
·
IF 9.405
Yan Wan,Lina Zhang,Yeyun Chen,Jinhan Lin,Wenda Hu,Shuai Wang,Jingdong Lin,Shaolong Wan,Yong Wang
The selective conversion of levoglucosan to gluconic acid, widely used in food and pharmaceutical industries, has been achieved in one pot by using a heterogeneous bifunctional catalyst comprising gold on Cs salts of tungstophosphates. With the concerted operation of active Au sites and acidic sites of Cs2.5H0.5PW12O40, gluconic acid was obtained with a high selectivity of 93.1% in nearly complete conversion. The gluconic acid product itself was found to accelerate the overall reaction rate, since the homogeneous Brønsted acidity introduced by gluconic acid could enhance the hydrolysis step of levoglucosan to glucose, a rate-limiting step as revealed by further kinetic analysis. This work provides a new and effective approach for the production of gluconic acid from levoglucosan, potentially enabling the efficient utilization of lignocellulose biomass to obtain value-added chemicals.
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RSC Advances
·
2019
·Vol. 9
·期 70
·40811-40818
·
IF 3.049
Xiaofang Zhang,Aixian Shan,Sibin Duan,Haofei Zhao,Rongming Wang,Woon-Ming Lau
Core/shell nanoparticles (NPs) of Au@Co2P, each comprising a Au core with a Co2P shell, were prepared, and shown to efficiently catalyze the oxygen evolution reaction (OER). In particular, Au@Co2P has a small overpotential of 321 mV at 10 mA cm−2 in 1 M KOH aqueous solution at room temperature, which is about 95 mV less than pure Co2P. More importantly, the Tafel slope of Au@Co2P, at 57 mV dec−1, is 44 mV dec−1 lower than that of Co2P. Hence, Au@Co2P outperforms Co2P drastically in practical production when a high current density is required.
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RSC Advances
·
2019
·Vol. 9
·期 66
·38590-38596
·
IF 3.049
Rong Huang,Lu Lu Xiong,Hui Hui Chai,Jing Jing Fu,Zhisong Lu,Ling Yu
A novel colorimetric aptasensor based on a Au/Fe3O4 nanohybrid was developed to detect ochratoxin A (OTA). The aptasensor is composed of a free OTA aptamer, a Au/Fe3O4 nanohybrid coated with biotinylated complementary DNA of the OTA aptamer (biotin-cDNA-Au/Fe3O4), and free alkaline-phosphatase-labeled streptavidin (SA-ALP). The Au/Fe3O4 nanohybrid not only immobilizes biotin-cDNA but also magnetically separates SA-ALP from the sample solution. One part of the OTA aptamer sequence hybridizes with biotin-cDNA immobilized on Au/Fe3O4, and the left part of the OTA aptamer sequence covers the biotin and blocks the specific interaction between biotin and SA-ALP. OTA can interrupt the interaction of OTA aptamer binding to biotin-cDNA-Au/Fe3O4 and can inhibit the shielding effect of the OTA aptamer on biotin. The amount of SA-ALP that can be captured by biotin-cDNA-Au/Fe3O4 thus increases with increasing OTA concentration. Through a simple magnetic separation, the collected SA-ALP-linked Au/Fe3O4 can produce a yellow-colored solution in the presence of p-nitrophenyl phosphate (p-NPP). This colorimetric aptasensor can detect OTA as low as 1.15 ng mL−1 with high specificity.
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