查找使用阿拉丁产品的科研文献

A ZnO/ZnFe2O4 n–n heterojunction and Au loading synergistically improve the sensing performance of acetone

Qixuan Qin,Asu Li,Yizhuo Fan,Xindong Zhang

In this work, Au nanoparticle-loaded ZnO/ZnFe2O4 (Au-ZnO/ZnFe2O4) microspheres were prepared using a combination of a two-step hydrothermal process and a co-precipitation method. The SEM and TEM analyses showed that the synthesized Au-ZnO/ZnFe2O4 samples were microspheres with a yolk–shell structure assembled from nanosheets. Gas-sensitive performance tests indicated that Au-ZnO/ZnFe2O4 showed the highest response to 100 ppm acetone (18.18), higher than those of ZnFe2O4 (8.4) and ZnO/ZnFe2O4 (11.6). In addition, the optimum operating temperature of Au-ZnO/ZnFe2O4 decreased from 279 to 206 °C compared to ZnFe2O4 and ZnO/ZnFe2O4. In addition, Au-ZnO/ZnFe2O4 yolk–shell microspheres exhibited fast response and recovery times (4 and 23 s, respectively). The sensor has a lower limit of acetone detection (0.7 ppm) at 85% RH and is able to effectively differentiate diabetic patients from healthy subjects by detecting acetone in their exhaled breath. The enhanced response of Au-ZnO/ZnFe2O4-based sensor is attributed not only to its high specific surface area but also to the synergistic effect of the n–n heterojunction structure of ZnO-ZnFe2O4 and the catalysis of Au nanoparticles.

Surface enhanced Raman scattering based on ZnO/Cu@Ag heterojunction for detecting γ-aminobutyric acid molecules

Li Yang,Qixin Chen,Yiheng Yuan,Xishun Peng,Xinghua Li,Cheng Zuo,Zhangyu Zhou,Zhongchen Bai

Detecting γ-aminobutyric acid (GABA) in the mammalian body is vital for diagnosing neurological disorders. Here, we introduced a novel SERS sensor based on metal-semiconductor heterojunction ZnO/Cu@Ag substrate for highly sensitive detecting GABA molecules. The ZnO/Cu@Ag substrate fully leverages the electromagnetic field enhancement effect and the chemical enhancement effect of metal-semiconductors heterojunction, exhibiting an excellent enhancement factor of 2.23 × 10 6 and a low limit-of-detection (LOD) of 3.84 nM for GABA molecules in water. Moreover, the ZnO/Cu@Ag substrate could recognize 10 nM GABA molecules in human serum. This GABA SERS sensor provides a reliable tool and technological support for research and applications in neuroscience and medicine.

Influence of ZnO nanoparticles on anammox granules: The inhibition kinetics and mechanism analysis by batch assays

Yu-Xia Song,Li-Yuan Chai,Chong-Jian Tang,Ruiyang Xiao,Bing-Rong Li,Di Wu,Xiao-Bo Min

The spread application of nanoparticles (NPs) would cause instability on anaerobic ammonium oxidation (anammox) process. The present study focused on the short-term evaluation of ZnO nanoparticles (NPs) on anammox process by batch tests. Results indicated that a significant inhibition occurred under ZnO NPs stress of 5–100 mg gVSS −1 . The half inhibitory concentration (IC 50 ) of ZnO NPs was found to be 11.6 mg gVSS −1 . The release of zinc ions from ZnO NPs dissolution was confirmed to be the main mechanism of inhibition on anammox activity. Haldane kinetic model simulation results confirmed that ZnO NPs imposed a non-competitive inhibition on nitrite conversion by decreasing maximum nitrogen removal rate ( q max ), while they showed a competitive inhibition on ammonium conversion kinetics with affinity constant ( K s ) increasing by 6 times. From the competitive inhibition results, it is suggested that the inhibition caused by ZnO NPs could be alleviated and recovered under higher ammonium concentrations.

Two-step synthesis of highly emissive C/ZnO hybridized quantum dots with a broad visible photoluminescence

Liangjie He,Shiliang Mei,Qiuhang Chen,Wanlu Zhang,Jie Zhang,Jiatao Zhu,Guoping Chen,Ruiqian Guo

In situ growth of ZnO layer on the surface of carbon dots was realized via a two-step method, which resulted in an enhancement of the broad visible emission with a high quantum yield. Influence of the refluxing time, the temperature and the oleylamine/octadecene ratio was investigated to address the key factors on the preparation of the carbon dots. Under the optimal conditions, the carbon dots with an average diameter of 3.4   ±   0.4   nm and a photoluminescence quantum yield of 29.3% were achieved. Remarkable improvements of photoluminescence were achieved by the hybridization of the ZnO layer, which can eliminate the surface-trap from the C cores and form the new centers of emission. The synergistic effect arising from the C/ZnO hybridized structure obviously broadened the visible emission and enhanced their photoluminescence quantum yield from 29.3% to 47.3%. The as-prepared highly emissive quantum dots exhibited a broad and stable emission with the Commission Internationaled ‘E’ clairage chromaticity coordinate of (0.23, 0.34), which could offer a promising solution for the future-generation white light emitting diodes.

Ethanolamine Modified ZnO Nanorods-Based Disposable Gate-AlGaN/GaN High Electron Mobility Transistor for pH Sensing

Zhiqi Gu,Jin Wang,Bin Miao,Xinsheng Liu,Lei Zhao,Huoxiang Peng,Dongmin Wu,Jiadong Li

Size-dependent strong metal–support interaction in Pd/ZnO catalysts for hydrogenation of CO2 to methanol

Liangcai Zhang,Xinyu Liu,Hengwei Wang,Lina Cao,Chenxi Huang,Shang Li,Xiaohui Zhang,Qiaoqiao Guan,Xiang Shao,Junling Lu

Strong metal–support interaction (SMSI) has long been studied in catalytic reactions. Proper utilization of the SMSI effect might not only improve the stability of the catalysts, but also the activity and selectivity. In this work, using the atomic layer deposition (ALD) technique, we synthesized a series of Pd/ZnO catalysts with Pd particle sizes ranging from 1.6 to 7.9 nm. Upon H2 reduction at elevated temperatures, these Pd/ZnO catalysts display a size-dependent SMSI effect wherein the larger-size Pd particles are more prone to be encapsulated by ZnO compared to the smaller ones. In the reaction of CO2 hydrogenation, we show that such size-dependent SMSI, together with the size-related CO binding strength on Pd particles, provides a higher activity and methanol selectivity to the Pd particles larger than ~2.5 nm.

ZnO nanorods anchored on CNTs incorporating carbon cloth flexible electrode as a highly sensitive electrochemical sensor

Fengna Shi,Jingfang Li,Cheng Chen,Fang Wang,Naipin Chen,Ziqi Xu,Jiajun Wang

Monitoring glucose, uric acid (UA) and hydrogen peroxide (H2O2) concentration has emerged as a critical health care issue to prevent acute complications and to minimize the hazard of long-term complications. In this paper, a novel non-enzyme electrochemical sensor was proposed with nanorod-like zinc oxide anchored on carbon nanotubes using a direct precipitation method and then decorated onto carbon cloth (ZnO/CNTs/CC). The ZnO/CNTs composite was characterized by x-ray photoelectron spectroscopy (XPS), Raman spectrum, TEM microscope and electrochemistry. The sensing of UA, glucose and H2O2 individually or simultaneously was done on a ZnO/CNTs/CC electrode, and the superior performance lies in its wide linear range, low detection limit and high selectivity, which is attributed to the synergistic effect of (a) the good electrocatalytic activity of ZnO nanorods, and (b) the large surface area with high conductivity offered by CNTs. Moreover, the ZnO/CNTs/CC electrode showed good reproducibility, stability and selectivity. Importantly, the developed sensor platform has been successfully applied to probe glucose, UA and H2O2 in human serum with satisfactory recoveries. Our proposed approach is simple in fabrication and operation, which provides a straightforward assay for the reliable and cost-effective determination of glucose, UA and H2O2 in clinical diagnosis and biomedical applications.

Spontaneous polarisation of ferroelectric BaTiO3/ZnO heterostructures with enhanced performance in a Fenton-like catalytic reaction

Yan Wang,Liangliang Liu,Weixing Zhao,Rong Ma,Jiaojiao Pang,Dengwei Hu,Zhen Dou,Meng Song,Tong Li,Kangkang Miao

Ferroelectric BaTiO 3 /ZnO heterojunction catalysts synthesised via the sol–gel method present obvious enhancements in spontaneous polarisation-driven Fenton-like catalytic activity. In this study, the oxidative decomposition of methylene blue (MB) dye was used as a model reaction. Pure BaTiO 3 -activated potassium monopersulphate (PMS) could decompose up to 48% of MB dye in an aqueous solution after 40 min. MB degradation rate firstly increased and then decreased as the ZnO content of the ferroelectric BaTiO 3 /ZnO heterojunction materials was increased. The maximum degradation rate of 100% and good cycling stability were observed when the BaTiO 3 :ZnO molar ratio was 1:1. Three active species, namely, holes (h + ), sulphate radicals (SO 4 •− ) and hydroxyl radicals (OH • ), were produced following the spontaneous polarisation-driven catalytic degradation of the dye. Amongst these species, h + and SO 4 •− were the main active species. Enhancements in the Fenton-like catalytic activity of BaTiO 3 /ZnO may be attributed to the formation of semiconductor heterojunctions, which could improve the spontaneous polarisation strength of ferroelectric BaTiO 3 , promote the effective separation of e − –h + pairs and accelerate PMS activation. In summary, a novel PMS activation method was developed to provide a nontoxic, efficient and environmentally friendly technology for the degradation of organic pollutants.

Enhanced photoelectrochemical performance based on conformal and uniform ZnO/ZnSe/CdSe heterostructures on Zn foil substrate

Changlin Li,Yanfang Wang,Shangrong Chen,Wei Zhang,Zi Wang,Zhongyu Hou

The erosion issue of ZnO nanorod arrays (NRAs) film is the major obstacle in surface sensitization of ZnO NRAs grown on Zn foil substrate for photoelectrochemical (PEC) applications. In this paper, PEC performance of ZnO NRAs grown on Zn foil substrate was greatly enhanced by coating ZnSe and CdSe on the surface of ZnO NRAs. Dense ZnO NRAs were in - situ grown on seed-free Zn foil substrate in a NH 3 ·H 2 O and NaOH hydrothermal system. ZnSe/CdSe co-sensitized ZnO heterostructures were then successfully synthesized using ZnO NRAs as precursors by two successive in - situ ion exchanges without damaging Zn foil and ZnO NRAs film. To obtain optimal photoconversion efficiency, anion exchange time and temperature were optimized. ZnO/ZnSe/CdSe heterostructures with optimized structure were shown as a layer of compact ZnSe/CdSe nanofilm conformally and uniformly coated on ZnO NRAs, which leads to efficient separation of photogenerated carriers , significant enhancement in visible-light absorption, and excellent PEC performance with photocurrent density of 3.008 mA/cm 2 (−0.2 V vs . Ag/AgCl) and photoconversion efficiency of 1.99% (0.418 V vs . RHE in polysulfide electrolyte solution), 27.55 and 40.61 times higher than those of ZnO NRAs, respectively.

Synthesis of ZnO and CuO co-decorated porous carbon spheres with simultaneous accessibility to small biomelucules

Wensheng Tan,Ziming Zhu,Jing Yang,Hongda Li,Shan Li,Datong Wu,Yong Qin,Yong Kong

ZnO and CuO co-decorated porous carbon spheres (PCS) were prepared via a simple hydrothermal method, denoted as ZnO-CuO/PCS. An electrochemical sensor based on the ZnO-CuO/PCS was fabricated for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Three well-resolved anodic peaks along with greatly increased peak currents were obtained at the ZnO-CuO/PCS modified glassy carbon electrode (GCE) on the differential pulse voltammograms. The anodic peak separations at the ZnO-CuO/PCS/GCE were 204 mV between AA and DA and 132 mV between DA and UA. Notably, the analytical performances of the ZnO-CuO/PCS outperform those of ZnO/PCS and CuO/PCS, which can be attributed to the synergistic effect of the two metallic oxides, i.e., the formation of p-n heterojunctions between p-type CuO and n-type ZnO allows sensitive transduction into remarkable changes in the electrochemical signals. The ZnO-CuO/PCS/GCE also presented high anti-interference ability, storage stability and repeatability in the determination of AA, DA and UA. Finally, the practical applicability of the prepared sensor was successfully demonstrated by the simultaneous determination of AA, DA and UA in human urine samples.

Earth abundant ZnO/CdS/CuSbS2 core-shell nanowire arrays as highly efficient photoanode for hydrogen evolution

Rong-Rong Su,Yu-Xiang Yu,Yong-Hao Xiao,XianFeng Yang,Wei-De Zhang

CuSbS 2 is regarded as a promising photo-absorber for solar energy conversion due to its proper bandgap, high absorptivity and earth abundance. Herein, novel low-cost ZnO/CdS/CuSbS 2 core-shell nanowire arrays were constructed as photoanode for hydrogen evolution through non-aqueous electrodeposition and cation exchange. The nanowire demonstrates even and compact multilayer structure. The optimal ZnO/CdS/CuSbS 2 photoanode achieves a photocurrent of 6.48 mA/cm 2 at 0 V versus Ag/AgCl and the remarkable IPCE value with approximately 52% at 480 nm in an electrolyte solution containing 0.35 mol/L Na 2 SO 3 and 0.25 mol/L Na 2 S. It also exhibited a good stability, maintained 87.9% of the initial current after 1 h measurement. The high performance benefits from well-crystalline and compact multilayer structure, high absorptivity of CuSbS 2 and CdS, p-n junction formed between CdS and CuSbS 2 which promotes the electron-hole separation and ZnO nanowire array as three dimensional scaffolds for electron percolation pathway. This work suggests the potential applications of low-cost p-n junction core-shell nanowire arrays as a highly efficient photoanode for hydrogen evolution in oil-field waste water with reductive sulfide.

Metal-organic frameworks derived ZnO@MOF@PZS flame retardant for reducing fire hazards of polyurea nanocomposites

Rongzhen Wang,Yan Chen,Yanyan Liu,Mingliang Ma,Zhouyu Tong,Xilei Chen,Yuxin Bi,Weibo Huang,Zijian Liao,Shuailiang Chen,Xinyi Zhang,Qianqian Li

Transition metal as flame retardant has attracted intense interests in recent years. In this work, ZnO@MOF@PZS was prepared via hydrothermal and polycondensation methods. ZnO nanoflowers played the role as a template for growth of MOF@PZS and zinc source for formation of MOF. Subsequently, the obtained ZnO@MOF@PZS was mixed into polyurea (PUA) to investigate its flame retardancy and toxicity suppression properties. The cone calorimeter test (CCT) showed that ZnO@MOF@PZS significantly improved the flame retardancy of PUA composites. The addition of 3 wt% ZnO@MOF@PZS into PUA could result in peak heat release rate (PHRR), total heat release (THR) and total CO production (TCO) of 28.30%, 19.59% and 36.65%, respectively. The result of universal testing machine showed that ZnO@MOF@PZS-add PUA had better mechanical properties. It is notable that the improved flame retardant properties for PUA composites are mainly attributed to ZnO@MOF@PZS promoting the formation of dense char residue.