Enzymeless electrochemical determination of hydrogen peroxide at a heteropolyanion-based composite film electrode

Size-tunable platinum nanoparticles (PtNPs) prepared by a facile method in an aqueous environment without the use of catalyst-poisoning reagents are used here in the electrocatalytic detection of hydrogen peroxide. Spherical nanoparticles with sizes as small as 4 and 20 nm are obtained as shown by transmission electron microscopy (TEM) analysis only using small easy-to-remove molecules such as sodium citrate. PtNPs are freed from the citrate capping agent at the surface by changing the pH to basic values and then deposited on a glassy carbon electrode by a very simple and rapid drop-casting method, achieving high cleanliness of the nanoparticle surface without the need for further treatments. The superior quality of nanoparticles on the glassy carbon is further investigated by scanning electron microscopy (SEM) analysis, which shows a highly homogeneous distribution of well-dispersed nanoparticles on the electrode surface, as well as by X-ray photoelectron spectroscopy (XPS) analysis, which confirms a drastic decrease of the citrate content, providing useful information about the citrate–platinum interaction, and evidences a related remarkable increase of conductivity of capping-free washed nanoparticles. Due to such key features, PtNPs possess excellent electrocatalytic properties, which have been tested in hydrogen peroxide electroreduction, a well-known catalytic reaction of nanostructured platinum materials. The size effect on PtNPs electrocatalytic properties is demonstrated, achieving higher performances with smaller NPs in the amperometric detection of hydrogen peroxide at −0.1 V in the concentration range of 25–750 μM, with a detection limit of 10 μM. Good sensing results toward hydrogen peroxide have also been obtained in terms of sensitivity, selectivity, repeatability, stability, and in tests performed in tap water samples. In addition, the strong adhesion of nanoparticles to the electrode surface has been verified and ascribed to their coating-free surface.

Section: Introductionmentioning

confidence: 99%

Bare Platinum Nanoparticles Deposited on Glassy Carbon Electrodes for Electrocatalytic Detection of Hydrogen Peroxide

Mazzotta

Giulio

Mastronardi

et al. 2021

“…According to the above electrochemical experimental results and the reported literature, − the electrocatalytic mechanism of β-Mo 2 C/C/GCE to H 2 O 2 can be described as follows …”

Section: Resultsmentioning

confidence: 87%

Carbon-Doping Mesoporous β-Mo₂C Aggregates for Nanomolar Electrochemical Detection of Hydrogen Peroxide

Song

Deng

et al. 2020

The development of a nonenzymatic electrochemical sensor with nanomolar detection of H2O2 has been highly desirable due to its wide applications in bioanalysis. In this paper, the glassy carbon electrode (GCE) modified by carbon-doping molybdenum carbide (β-Mo2C/C/GCE) was simply fabricated by simple drop-coating method and used to detect H2O2 in pretreated human serum. The β-Mo2C/C hierarchical structure is obtained by a one-step pyrolysis of the single-crystal [(H2L)2(Mo8O26)] n [L = N,N′-bis(3-pyridin)-1,4-xylyenediamine] and constructed from amounts of nanoparticles (∼10 nm) with a mesoporous size distribution of 42.46 nm. At room temperature, the β-Mo2C/C/GCE sensor has a high sensitivity of 247.73 μA mM–1 cm–2, a low detection limit of 90 nM (signal/noise = 3), as well as a wide linear range of 0.27 μM–2.39 mM, and it shows better electrocatalytic performance of H2O2 than the molybdenum oxide (obtained from the same precursor) modified glassy carbon electrode (α-MoO3/GCE). Such outstanding electrocatalytic performances are related to the synergistic effect of the inherent characteristics of the β-Mo2C/C material. The satisfactory test results of the human serum samples indicate that the β-Mo2C/C/GCE sensor can be used as a good candidate for real-time detection of H2O2 in biological, food, and environmental fields.

“…The bimetallic alloy Au-AgNPs-COF/GCE showed the maximum k et value compared to the other electrodes, which agrees with the R ct results. Then, the electrochemical active surface area of the modified electrodes was calculated using Randles–Sevcik eq . , where n , A , D , C , and ν stand for their universal meanings . The electroactive surface areas were calculated to be 0.06, 0.13, 0.26, 0.42, and 0.63 cm 2 for the bare GCE, COF/GCE, AgNPs-COF/GCE, AuNPs-COF/GCE, and Au-AgNPs-COF, respectively.…”

Section: Resultsmentioning

confidence: 99%

Gold–Silver Bimetallic Alloy Nanoparticles in a Covalent Organic Framework for Real-Time Monitoring of Hydrogen Peroxide from Live Cells

Arul

Huang

Mani

2022

An efficient and simple way has been described to prepare gold and silver bimetallic alloy nanoparticles (Au-AgNPs) in an organic framework with a metal-free core. The growth of alloy Au-AgNPs was monitored by UV–visible spectroscopy (UV–vis) and confirmed using various spectral, microscopy, and electrochemical techniques. The field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results revealed that the covalent organic framework (COF) had a uniform flake-like morphology, and the alloy-based Au-AgNPs had a flower-like structure. The results of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) indicated that Au-AgNPs are metallic in nature and highly crystalline. The surface of a glassy carbon electrode (GCE) was then modified with Au-AgNPs-COF, which was subsequently employed for enzyme-free electrochemical reduction of H2O2. The electrocatalytic cyclic voltammetry performance of the different modified electrodes was in the following order: COF (−14.82 μA) < AgNPs-COF (−26.95 μA) < AuNPs-COF (−31.78 μA) < Au-AgNPs-COF (−46.15 μA). The Au-AgNPs-COF/GCE displayed an excellent electrocatalytic activity toward reduction of H2O2, over a dynamic range of 2.0 nM–1.0 mM with a limit of detection (LOD) of 0.44 nM (S/N = 3). Furthermore, the present sensor showed appreciable selectivity, stability, and reproducibility against the reduction of H2O2. Practicality was demonstrated in fetal bovine serum (FBS), cat blood serum (CBS), and living cells (RAW 264.7).