A non-enzymatic hydrogen peroxide sensor based on platinum nanoparticle– polyaniline nanocomposites hosted in mesoporous silica film
Longhua Ding, Bin Su
Reference: JEAC 1877
To appear in: Journal of Electroanalytical Chemistry
Received Date: 5 September 2014
Revised Date: 30 October 2014
Accepted Date: 1 November 2014
Please cite this article as: L. Ding, B. Su, A non-enzymatic hydrogen peroxide sensor based on platinum nanoparticle–polyaniline nanocomposites hosted in mesoporous silica film, Journal of Electroanalytical
Chemistry (2014), doi: http://dx.doi.org/10.1016/j.jelechem.2014.11.001
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A non-enzymatic hydrogen peroxide sensor based on platinum nanoparticle–polyaniline nanocomposites hosted in mesoporous silica film
Longhua Ding and Bin Su*
Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University,
Zhejiang, Hangzhou, 310058, China *Corresponding Author: Fax: +86-571-88272572; E-mail: firstname.lastname@example.org
We demonstrated a facile method for supporting platinum nanoparticles (PtNPs) on polyaniline (PANI)/mesoporous silica film (MSF). The MSF with mesochannels perpendicular to the underlying electrode surface can confine the electrodeposition of
PANI and improve the mechanical strength of PANI. The secondary amines and tertiary imines on the PANI backbone can readily complex with PtCl6 2 ions, which can be further reduced to generate Pt nanoparticles (NPs). The obtained
PtNPs@PANI/MSF hybrid material was characterized by transmission electron microscopy and energy dispersive X-ray spectroscopic analysis. It also exhibited a good electrocatalytic activity toward oxidation of H2O2 and can be used to detect
H2O2 with a high sensitivity (50 mM 1 ) in a wide concentration range (1.0 - 2000 ).
Keywords: Pt nanoparticles, Polyaniline, Mesoporous silica, Electrocatalysis, H2O2 3 1. Introduction
Metal nanoparticles (NPs) have continued to receive considerable interest due to the distinctly different physicochemical properties compared to their bulk counterparts, which led to numerous potential applications in optical, electronic, catalysis and sensing [1-2]. In particular, a lot of research works have concentrated on platinum (Pt) and Pt-alloys because of their high activities [3-5]. However, most of the metal NP based catalysts may undergo aggregation or suffer from poisoning under the reaction conditions, resulting in the deactivation and loss of catalytic activity [6-7]. Addition of organic ligands or preparation of supported metal NPs can effectively solve this problem [8-9]. For example, metal NPs can be dispersed on various porous materials, including metal oxides, carbon and polymers [10-13].
Moreover, a suitable supporting material may have a significant effect on the catalytic activity owing to the interactions and surface reactivity with supported NP catalysts . Among them, conducting polymer supported metal NPs have attracted many research efforts, due to the synergetic properties pertaining of the two components [15-18]. So far, there are many reports on loading PtNPs on conducting polymers for applications in electrochemical sensors [2, 24], dye-sensitized solar cell , regioselective hydrosilylation reactions  and so on.
Herein we report a facile procedure to support PtNPs on polyaniline (PANI) spatially confined in channels of mesoporous silica film (MSF). PANI is one of the most studied conducting polymer hosts due to its facile synthesis, controllable 4 electronic conductivity, relatively high chemical stability and potential applications in many areas [19-23]. Confining PANI in the pores of MSF can improve the poor mechanical strength of conducting polymers [27-29] and increase the surface-to-volume ratio . After being dedoped in an alkaline solution, the secondary amines and tertiary imines on the PANI backbone can readily complex with
PtCl6 2 ions. Upon further chemical reduction with NaBH4, PtNPs were produced and loaded onto the PANI-MSF. Thus obtained hybrid material, designated
PtNPs@PANI-MSF, exhibited a good electrocatalytic activity and sensing capability toward hydrogen peroxide (H2O2). 2. Materials and Methods 2.1 Chemicals and materials
All chemicals used were analytical grade or higher. Perchloric acid (HClO4), potassium perchlorate (K2PtCl6), concentrated ammonia aqueous solution (25 wt%), potassium hydrogen phthalate (KHP) and aniline were ordered from Aladdin.
Hydrochloric acid (HCl) was obtained from Hangzhou Chemicals. Tetraethoxysilane (TEOS), cetyltrimethylammonium bromide (CTAB) and hexaammineruthenium (III) chloride (Ru(NH3)6Cl3, 98%) were purchased from Sigma-Aldrich. Sodium borohydride (NaBH4) was bought from Alfa Aesar. Aniline was distilled at reduced pressure prior to use. Anhydrous ethanol, acetone and sodium hydroxide (NaOH) were supplied by Sinopharm. Indium tin oxide (ITO) coated glass (thickness of 100 nm, resistance of <15 /square) was ordered from Zhuhai Kaivo Electronic 5
Components. Prior to use, the ITO glass was treated with 1 M NaOH solution overnight to remove the organic residues, and then sonicated in acetone, ethanol and deionized water sequentially for 10 min. Finally, cleaned ITO glasses were dried with a nitrogen stream. Deionized water (18.2 Mcm) was used in all experiments. 2.2 Preparation of MSF and PtNPs@PANI-MSF
MSF was synthesized on ITO electrode with stöber-solution method as previously reported . Typically, ITO electrodes were immersed in solution containing 0.16 g cetyltrimethylammonium bromide (CTAB), 70 mL water, 30 mL ethanol, 10 L ammonia aqueous solution and 80 L tetraethoxysilane (TEOS). After 24 h, MSF coated ITO electrodes were taken out, rinsed with water and dried at 100 o