Elsevier

Materials Letters

Volume 264, 1 April 2020, 127333
Materials Letters

Morphology dependent activity of PbS nanostructures for electrochemical sensing of dopamine

https://doi.org/10.1016/j.matlet.2020.127333Get rights and content

Highlights

  • Synthesis of lead sulfide nanostructures by facile thermal decomposition approach.

  • Morphology dependent electrochemical characteristics of PbS nanostructures.

  • PbS dendrites exhibits high electrochemical activity of towards dopamine sensing.

  • Nanoparticles facilitate the enhance electron transfer by serving as the medium.

  • Modified electrodes showed better activity due to improved surface characteristics.

Abstract

The present study reports synthesis of lead sulfide nanostructures by a facile thermal decomposition approach. Morphology dependent electrochemical characteristics have been investigated using cyclic voltammetry. PbS dendrites exhibit higher redox peak current and smaller peak potential separation compared to PbS nanocubes. Enhanced redox current, reduced peak potential, well-defined and stable redox wave indicate high electrocatalytic activity of PbS nanostructures towards dopamine. The crystallite size of dendrites and nanocubes was found to be 18.9 nm and 50.8 nm. The surface area of electrodes increased multi-fold on modification with PbS nanostructures (9.7 mm2) compared to bare electrode (1.2 mm2).

Graphical abstract

PbS micro-nanostructures exhibit morphology dependent activity, show favourable electrocatalytic activity and offer effective platform for electrochemical sensing of dopamine.

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Introduction

Lead sulfide is an interesting semiconductor and an ideal material for studying quantum size due to narrow direct band gap (0.41 eV for bulk), large exciton Bohr radius (18 nm), strong quantum confinement and high carrier mobility [1]. It is a promising material useful for various applications such as optoelectronics catalysis, sensing and biological applications [2]. Dopamine is a neurotransmitter and has a great influence on the central nervous, renal, hormonal and cardiovascular systems [3]. Abnormal levels of dopamine may result in a variety of diseases, such as schizophrenia, Huntington's disease, Parkinson’s disease, and dementia [4]. Detection of dopamine and monitoring its concentrations helps in early diagnosis of diseases and this calls for development of selective and sensitive sensing techniques. Dopamine is electrochemically active (oxidizable) hence, use of electrochemical sensors is an effective option for sensing of dopamine [5]. It has many advantages such as low cost, easy operation, fast, low detection limit, high sensitivity and selectivity over other methods [3], [6] Although, various modified electrodes have been employed to enhance the voltammetric selectivity and sensitivity towards dopamine determination, it is still attractive to develop novel materials for sensitive determination of dopamine. In the present study attempts have been made to demonstrate morphology dependent electrocatalytic activity of PbS nanostructure for dopamine sensing using cyclic voltammetry (CV).

Section snippets

Reagents used

Lead acetate dihydrate, thiourea, ethylene glycol, phosphate buffer solution (PBS) (pH 7), potassium ferricyanide K3[Fe(CN)6]), potassium chloride, dopamine (Aldrich®, 99%), methanol, ethanol and Millipore® water. All the chemicals were used as received (Rankem, 99%), except methanol (distilled).

Synthesis of PbS nanostructures

PbS nanostructures were synthesized by thermal decomposition approach as per report [2]. Lead acetate and thiourea were dissolved in minimum amount of ethylene glycol (~2mL) and then added to preheated

Structural & morphological studies

Fig. 2a shows the X-ray diffraction (XRD) patterns of S2-5 and S2-180, field-emission scanning electron microscope (FE-SEM) images are shown in the insets. The XRD patterns of all the samples match with cubic PbS (JCPDS No. 78-1901). The peaks at 2θ values of 25.98°, 30.10°, 43.10°, 51.02°, 53.47°, 62.59°, 68.95°, 71.01° and 79.02° are attributed to (111), (200), (220), (311), (222), (400), (331), (420) and (422) reflections, respectively. The crystallite size of PbS was calculated using

Conclusion

PbS dendrites exhibit enhanced redox current, reduced peak potential, well-defined and stable redox wave which indicate high electrocatalytic activity towards dopamine. PbS nanocubes show poor electrochemical response with reduced redox current and high peak potential. The variance in the electrocatalytic activity of dendrites and nanocubes towards oxidation of dopamine, is attributed to smaller crystallite size and high surface area of dendrites. The results suggest that PbS nanoparticles

CRediT authorship contribution statement

Rama Gaur: Conceptualization, Methodology, Data curation, Writing - original draft, Validation, Investigation, Writing - review & editing, Visualization.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The author would like to thank Prof. P. Jeevanandam, Department of Chemistry, Indian Institute of Technology Roorkee, for his guidance and Institute Instrumentation Centre, IIT Roorkee for the instrumental facilities.

References (11)

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