Design and Characterization of Effective Ag, Pt and AgPt Nanoparticles to H2O2 Electrosensing from Scrapped Printed Electrodes

Abstract

The use of disposable screen-printed electrodes (SPEs) has extraordinarily grown in the last years. In this paper, conductive inks from scrapped SPEs were removed by acid leaching, providing high value feedstocks suitable for the electrochemical deposition of Ag, Pt and Ag core-Pt shell-like bimetallic (AgPt) nanoparticles, onto screen-printed carbon electrodes (ML@SPCEs, M = Ag, Pt or AgPt, L = metal nanoparticles from leaching solutions). ML@SPCEs were characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The results were compared to those obtained when metal nanoparticles were synthesised using standard solutions of metal salts (MS@SPCEs). Both ML@SPCEs and MS@SPCEs exhibited similar cyclic voltammetric patterns referred to the electrochemical stripping of silver or the adsorption/desorption of hydrogen/anions in the case of platinum, proving leaching solutions extremely effective for the electrodeposition of metallic nanoparticles. The use of both ML@SPCEs and MS@SPCEs proved effective in enhancing the sensitivity for the detection of H2O2 in phosphate buffer solutions (pH = 7). The AgPtL@SPCE was used as proof of concept for the validation of an amperometric sensor for the determination of H2O2 within laundry boosters and antiseptic samples. The electrochemical sensor gave good agreement with the results obtained by a spectrophotometric method with H2O2 recoveries between 100.6% and 106.4%.

Screen-Printed Electrodes Modified with Metal Nanoparticles for Small Molecule Sensing

“…The parameters usually optimized are separated in two main groups: The ones related to the precursor solution where the salt type and concentration are involved, and the conditions of electrochemical deposition. A list of usual salts employed are AgNO 3 [30][31][32][33][34] for silver NPs; HAuCl 4 [31,35,36] and AuCl 3 [37] for gold NPs; Bi(NO 3 ) 3 [16,38,39] for bismuth NPs; CoCl 2 [40] for cobalt NPs; CuCl 2 [41], CuSO 4 [42], and CuNO 3 [43,44] for copper NPs; NiCl 2 [40,45] and NiSO 4 [46,47] for nickel NPs; PdCl 2 [48][49][50] [30,[52][53][54][55][56], and PtCl 2 [37] for platinum NPs; RhCl 3 [57] for rhodium NPs, etc. Although higher concentrations of precursor allow bigger particles to be obtained, the size and shape are usually controlled electrochemically; so, the precursor concentration usually tends to be high enough to have sufficient material susceptible to be deposited and it is not often optimized [33].…”

“…Galvanic displacement was also explored for bimetallic alloys' electrosynthesis [30]. It is based on the phenomenon observed when a moderately active metal is partially replaced (e.g., oxidized) by a less active or more noble metal.…”

“…Platinum is the most common noble metal employed for non-enzymatic sensors. Due to its good electrocatalytic activity towards peroxide, platinum can be used to detect this molecule in several real samples, such as cosmetics [53], household goods [30], or food and beverages [25], with good recoveries. A simple electrodeposition step is needed [37] to perform sensors with this method, affording a facile and robust methodology to monitor peroxide "in-situ" and making it even susceptible to academic demonstrations with hair lightener [56] and whitening strips [18] as real samples.…”

“…Metal alloys prepared with several elements, such as Pt-Ag [30] and Pt-Pd [54], afford a better response towards peroxide [30] and glucose [54] than each metal separately. Good detection is achieved in real samples, such as antiseptic and laundry boosters [30].…”

Glucose Biosensor Based on Disposable Activated Carbon Electrodes Modified with Platinum Nanoparticles Electrodeposited on Poly(Azure A)

“…Therefore, pre-treatments and modification protocols of the working electrode are made with the aim to enhance electro-transfer properties and sensitivity towards the compound of interest [ 18 , 25 ]. In particular, an H 2 O 2 -basedpre-treatment (carbon activation) [ 25 , 26 ], the polymerization of poly(Azure A) (PAA) using dodecyl sulphate (DS) as a doping ion [ 19 , 27 ], and the electrodeposition of platinum nanoparticles (PtNPs) [ 18 , 28 ] on screen-printed carbon electrodes (SPCEs) have demonstrated excellent electrochemical properties in the measurement of H 2 O 2 . Recently, our research group published a novel non-enzymatic H 2 O 2 sensor based on PtNPs electrochemically deposited on a PAA film previously electrogenerated on screen-printed carbon electrodes whose surface was previously activated by H 2 O 2 (aSPCEs) [ 29 ].…”