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Electrochemical Co-Reduction Synthesis of AuPt Bimetallic Nanoparticles-Graphene Nanocomposites for Selective Detection of Dopamine in the Presence of Ascorbic Acid and Uric Acid.

Zhao Z, Zhang M, Chen X, Li Y, Wang J - Sensors (Basel) (2015)

Bottom Line: In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6.The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3).The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China. zhaozongya2010@stu.xjtu.edu.cn.

ABSTRACT
In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6. The as-prepared AuPt bimetallic nanoparticles-graphene nanocomposites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and other electrochemical methods. The morphology and composition of the nanocomposite could be easily controlled by adjusting the HAuCl4/H2PtCl6 concentration ratio. The electrochemical experiments showed that when the concentration ratio of HAuCl4/H2PtCl6 was 1:1, the obtained AuPt bimetallic nanoparticles-graphene nanocomposite (denoted as Au1Pt1NPs-GR) possessed the highest electrocatalytic activity toward dopamine (DA). As such, Au1Pt1NPs-GR nanocomposites were used to detect DA in the presence of ascorbic acid (AA) and uric acid (UA) using the differential pulse voltammetry (DPV) technique and on the modified electrode, there were three separate DPV oxidation peaks with the peak potential separations of 177 mV, 130 mV and 307 mV for DA and AA, DA and UA, AA and UA, respectively. The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3). The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

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(A) SEM image of GR; (B) SEM image of AuNPs-GR; (C) SEM image of Au1Pt2NPs-GR; (D) SEM image of Au1Pt1NPs-GR; (E) SEM image of Au2Pt1NPs-GR; (F) SEM image of PtNPs-GR; (G) XRD patterns of Au1Pt2-GR, Au1Pt1-GR and Au2Pt1-GR.
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sensors-15-16614-f001: (A) SEM image of GR; (B) SEM image of AuNPs-GR; (C) SEM image of Au1Pt2NPs-GR; (D) SEM image of Au1Pt1NPs-GR; (E) SEM image of Au2Pt1NPs-GR; (F) SEM image of PtNPs-GR; (G) XRD patterns of Au1Pt2-GR, Au1Pt1-GR and Au2Pt1-GR.

Mentions: The surface morphologies of the as-prepared nanocomposites were examined by scanning electron microscopy (SEM). As shown in Figure 1A, the surface morphology of GR film exhibited a typical wrinkled and crumpled structure. The surface morphology of AuNPs-GR (Figure 1B) showed that AuNPs with a quasi-spherical shape and relatively smooth surface were densely and uniformly distributed on the surface of GR. However, the surface morphology of PtNPs-GR (Figure 1F) showed that PtNPs with a spherical and flowerlike shape were sparsely distributed on the surface of GR sheets. It was obvious that the density of PtNPs was much lower than that of AuNPs, which indicated that the depositon of AuNPs on the surface of GR was much easier than that of PtNPs under the same electrochemical co-reduction conditions. Figure 1C–E displayed the SEM images of Au1Pt2NPs-GR, Au1Pt1NPs-GR and Au2Pt1NPs-GR, respectively. All AuPt alloy nanoparticles were formed as cauliflower-like shapes with rough surfaces, and the shapes and sizes changed with the different HAuCl4/H2PtCl6 concentration ratios. Specifically, with the increase of HAuCl4/H2PtCl6 concentration ratio (1:2, 1:1, 2:1), more smaller AuPt alloy nanoparticles appeared with an average diameter of 15 nm among the bigger cauliflower-like alloy nanoparticles with an average diameter of 45 nm. Although there were no higher magnification SEM images of the smaller AuPt alloy nanoparticles, it was assumed that these smaller AuPt alloy nanoparticles also possessed cauliflower-like shapes. The possible formation mechanisms of these cauliflower-like AuPt alloy nanoparticles was described as below: the growth of AuNPs was easier and faster on the surface of GR than that of PtNPs, and AuNPs tended to form nuclei during the growth process of AuNP bimetallic nanoparticles; subsequent growth of PtNPs occurred predominantly at the remaining Au seeds rather than onto the surface of GR; when the HAuCl4/H2PtCl6 concentration ratio increased, more gold seeds appeared on the surface of GR films, but there was not enough PtNPs to grow onto as-deposited gold nuclei, which resulted in more smaller AuPt alloy nanoparticles with the increase of HAuCl4/H2PtCl6 concentration ratio [43,44].


Electrochemical Co-Reduction Synthesis of AuPt Bimetallic Nanoparticles-Graphene Nanocomposites for Selective Detection of Dopamine in the Presence of Ascorbic Acid and Uric Acid.

Zhao Z, Zhang M, Chen X, Li Y, Wang J - Sensors (Basel) (2015)

(A) SEM image of GR; (B) SEM image of AuNPs-GR; (C) SEM image of Au1Pt2NPs-GR; (D) SEM image of Au1Pt1NPs-GR; (E) SEM image of Au2Pt1NPs-GR; (F) SEM image of PtNPs-GR; (G) XRD patterns of Au1Pt2-GR, Au1Pt1-GR and Au2Pt1-GR.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4541896&req=5

sensors-15-16614-f001: (A) SEM image of GR; (B) SEM image of AuNPs-GR; (C) SEM image of Au1Pt2NPs-GR; (D) SEM image of Au1Pt1NPs-GR; (E) SEM image of Au2Pt1NPs-GR; (F) SEM image of PtNPs-GR; (G) XRD patterns of Au1Pt2-GR, Au1Pt1-GR and Au2Pt1-GR.
Mentions: The surface morphologies of the as-prepared nanocomposites were examined by scanning electron microscopy (SEM). As shown in Figure 1A, the surface morphology of GR film exhibited a typical wrinkled and crumpled structure. The surface morphology of AuNPs-GR (Figure 1B) showed that AuNPs with a quasi-spherical shape and relatively smooth surface were densely and uniformly distributed on the surface of GR. However, the surface morphology of PtNPs-GR (Figure 1F) showed that PtNPs with a spherical and flowerlike shape were sparsely distributed on the surface of GR sheets. It was obvious that the density of PtNPs was much lower than that of AuNPs, which indicated that the depositon of AuNPs on the surface of GR was much easier than that of PtNPs under the same electrochemical co-reduction conditions. Figure 1C–E displayed the SEM images of Au1Pt2NPs-GR, Au1Pt1NPs-GR and Au2Pt1NPs-GR, respectively. All AuPt alloy nanoparticles were formed as cauliflower-like shapes with rough surfaces, and the shapes and sizes changed with the different HAuCl4/H2PtCl6 concentration ratios. Specifically, with the increase of HAuCl4/H2PtCl6 concentration ratio (1:2, 1:1, 2:1), more smaller AuPt alloy nanoparticles appeared with an average diameter of 15 nm among the bigger cauliflower-like alloy nanoparticles with an average diameter of 45 nm. Although there were no higher magnification SEM images of the smaller AuPt alloy nanoparticles, it was assumed that these smaller AuPt alloy nanoparticles also possessed cauliflower-like shapes. The possible formation mechanisms of these cauliflower-like AuPt alloy nanoparticles was described as below: the growth of AuNPs was easier and faster on the surface of GR than that of PtNPs, and AuNPs tended to form nuclei during the growth process of AuNP bimetallic nanoparticles; subsequent growth of PtNPs occurred predominantly at the remaining Au seeds rather than onto the surface of GR; when the HAuCl4/H2PtCl6 concentration ratio increased, more gold seeds appeared on the surface of GR films, but there was not enough PtNPs to grow onto as-deposited gold nuclei, which resulted in more smaller AuPt alloy nanoparticles with the increase of HAuCl4/H2PtCl6 concentration ratio [43,44].

Bottom Line: In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6.The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3).The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China. zhaozongya2010@stu.xjtu.edu.cn.

ABSTRACT
In this paper, AuPt bimetallic nanoparticles-graphene nanocomposites were obtained by electrochemical co-reduction of graphene oxide (GO), HAuCl4 and H2PtCl6. The as-prepared AuPt bimetallic nanoparticles-graphene nanocomposites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and other electrochemical methods. The morphology and composition of the nanocomposite could be easily controlled by adjusting the HAuCl4/H2PtCl6 concentration ratio. The electrochemical experiments showed that when the concentration ratio of HAuCl4/H2PtCl6 was 1:1, the obtained AuPt bimetallic nanoparticles-graphene nanocomposite (denoted as Au1Pt1NPs-GR) possessed the highest electrocatalytic activity toward dopamine (DA). As such, Au1Pt1NPs-GR nanocomposites were used to detect DA in the presence of ascorbic acid (AA) and uric acid (UA) using the differential pulse voltammetry (DPV) technique and on the modified electrode, there were three separate DPV oxidation peaks with the peak potential separations of 177 mV, 130 mV and 307 mV for DA and AA, DA and UA, AA and UA, respectively. The linear range of the constructed DA sensor was from 1.6 μM to 39.7 μM with a detection limit of 0.1 μM (S/N = 3). The obtained DA sensor with good stability, high reproducibility and excellent selectivity made it possible to detect DA in human urine samples.

Show MeSH
Related in: MedlinePlus