Pt nanoparticle-based highly sensitive platform for the enzyme-free amperometric sensing of H2O2

AgAuPt nanocages for highly sensitive detection of hydrogen peroxide

AgAuPt hybrid nanocages modified electrode showed high sensitivity for the detection of hydrogen peroxide.

Non-enzymatic Hydrogen Peroxide Sensors Based on Multi-wall Carbon Nanotube/Pt Nanoparticle Nanohybrids

A novel strategy to fabricate a hydrogen peroxide (H₂O₂) sensor was developed by using platinum (Pt) electrodes modified with multi-wall carbon nanotube-platinum nanoparticle nanohybrids (MWCNTs/Pt nanohybrids). The process to synthesize MWCNTs/Pt nanohybrids was simple and effective. Pt nanoparticles (Pt NPs) were generated in situ in a potassium chloroplatinate aqueous solution in the presence of multi-wall carbon nanotubes (MWCNTs), and readily attached to the MWCNTs convex surfaces without any additional reducing reagents or irradiation treatment. The MWCNT/Pt nanohybrids were characterized by transmission electron microscope (TEM), and the redox properties of MWCNTs/Pt nanohybrids-modified Pt electrode were studied by electrochemical measurements. The MWCNTs/Pt-modified electrodes exhibited a favorable catalytic ability in the reduction of H₂O₂. The modified electrodes can be used to detect H₂O₂ in the range of 0.01–2 mM with a lower detection limit of 0.3 μM at a signal-to-noise ratio of 3. The sensitivity of the electrode to H₂O₂ was calculated to be 205.80 μA mM⁻¹ cm⁻² at working potential of 0 mV. In addition, the electrodes exhibited an excellent reusability and long-term stability as well as negligible interference from ascorbic acid, uric acid, and acetaminophen.

Using multi-walled carbon nanotubes to enhance coimmobilization of poly(azure A) and poly(neutral red) for determination of nicotinamide adenine dinucleotide and hydrogen peroxide

Illustration of electro-codeposition of azure A and neutral red hybrid films using high ly conductive and steric MWCNTs as a template.

A comparative study of carbon–platinum hybrid nanostructure architecture for amperometric biosensing

This facile graph-onto methodology is highly efficient and competes with relatively complex graph-from synthesis of carbon–metal hybrid nanocomposites.

Synthesis of platinum nanoparticles using dried Anacardium occidentale leaf and its catalytic and thermal applications

An environment friendly approach for the synthesis of Pt nanoparticles (NPs) using dried leaf powder of Anacardium occidentale is reported. The formation of Pt NPs is monitored using UV-Vis spectrophotometer. FTIR spectra reveal that proteins are bound to Pt nanoparticles. TEM images show irregular rod shaped particles which are crystalline. The quantity of leaf powder plays a vital role in determining the size of particles. Synthesized NPs exhibit good catalytic activity in the reduction of aromatic nitrocompound. The effective thermal conductivity of synthesized Pt/water nanofluid has been measured and found to be enhanced to a good extent.

Preparation and characterization of three dimensional graphene foam supported platinum-ruthenium bimetallic nanocatalysts for hydrogen peroxide based electrochemical biosensors

The large surface, the excellent dispersion and the high degrees of sensitivity of bimetallic nanocatalysts were the attractive features of this investigation. Graphene foam (GF) was a three dimensional (3D) porous architecture consisting of extremely large surface and high conductive pathways. In this study, 3D GF was used incorporating platinum-ruthenium (PtRu) bimetallic nanoparticles as an electrochemical nanocatalyst for the detection of hydrogen peroxide (H2O2). PtRu/3D GF nanocatalyst exhibited a remarkable performance toward electrochemical oxidation of H2O2 without any additional mediator showing a high sensitivity (1023.1 µA mM(-1)cm(-2)) and a low detection limit (0.04 µM) for H2O2. Amperometric results demonstrated that GF provided a promising platform for the development of electrochemical sensors in biosensing and PtRu/3D GF nanocatalyst possessed the excellent catalytic activity toward the H2O2 detection. A small particle size and a high degree of the dispersion in obtaining of large active surface area were important for the nanocatalyst for the best H2O2 detection in biosensing. Moreover, potential interference by ascorbic acid and uric acid appeared to be negligible.

A colloidal suspension of nanostructured poly(N-butyl benzimidazole)-graphene sheets with high oxidase yield for analytical glucose and choline detections

A colloidal suspension of nanostructured poly(N-butyl benzimidazole)-graphene sheets (PBBIns-Gs) was used to modify a gold electrode to form a three-dimensional PBBIns-Gs/Au electrode that was sensitive to hydrogen peroxide (H2O2) in the presence of acetic acid (AcOH). The positively charged nanostructured poly(N-butyl benzimidazole) (PBBIns) separated the graphene sheets (Gs) and kept them suspended in an aqueous solution. Additionally, graphene sheets (Gs) formed "diaphragms" that intercalated Gs, which separated PBBIns to prevent tight packing and enhanced the surface area. The PBBIns-Gs/Au electrode exhibited superior sensitivity toward H2O2 relative to the PBBIns-modified Au (PBBIns/Au) electrode. Furthermore, a high yield of glucose oxidase (GOD) on the PBBIns-Gs of 52.3mg GOD per 1mg PBBIns-Gs was obtained from the electrostatic attraction between the positively charged PBBIns-Gs and negatively charged GOD. The non-destructive immobilization of GOD on the surface of the PBBIns-Gs (GOD-PBBIns-Gs) retained 91.5% and 39.2% of bioactivity, respectively, relative to free GOD for the colloidal suspension of the GOD-PBBIns-Gs and its modified Au (GOD-PBBIns-Gs/Au) electrode. Based on advantages including a negative working potential, high sensitivity toward H2O2, and non-destructive immobilization, the proposed glucose biosensor based on an GOD-PBBIns-Gs/Au electrode exhibited a fast response time (5.6s), broad detection range (10μM to 10mM), high sensitivity (143.5μAmM(-1)cm(-2)) and selectivity, and excellent stability. Finally, a choline biosensor was developed by dipping a PBBIns-Gs/Au electrode into a choline oxidase (ChOx) solution for enzyme loading. The choline biosensor had a linear range of 0.1μM to 0.83mM, sensitivity of 494.9μAmM(-1)cm(-2), and detection limit of 0.02μM. The results of glucose and choline measurement indicate that the PBBIns-Gs/Au electrode provides a useful platform for the development of oxidase-based biosensors.

Ultralow Pt-loading bimetallic nanoflowers: fabrication and sensing applications

Ultralow Pt-loading Au nanoflowers (AuNFs) were synthesized on a glassy carbon electrode surface by the underpotential deposition (UPD) monolayer redox replacement technique, which involves redox replacement of a copper UPD monolayer by PtCl(4)(2-) that can be reduced and deposited simultaneously. Field-emission scanning electron microscopy, energy dispersive spectroscopy, x-ray photoelectron spectroscopy and the electrochemical method were utilized to characterize the ultralow Pt-loading AuNFs. Cyclic voltammogram results showed that the ultralow Pt-loading AuNFs exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide and the oxidation of glucose in neutral media, and the reaction pathway of glucose oxidation was changed from an intermediate process based on the electrosorption of glucose to a direct oxidation process. From chronoamperometric results, it could be obtained that this prepared biosensor had wide linear ranges and very low detection limits (DLs) for H(2)O(2) (0.025-94.3 μM; DL = 0.006 μM) and glucose (0.0028-8.0 mM; DL = 0.8 μM), which were much better than previous results.

Facile synthesis of flower like copper oxide and their application to hydrogen peroxide and nitrite sensing

BACKGROUND

The detection of hydrogen peroxide (H2O2) and nitrite ion (NO2-) is of great important in various fields including clinic, food, pharmaceutical and environmental analyses. Compared with many methods that have been developed for the determination of them, the electrochemical detection method has attracted much attention. In recent years, with the development of nanotechnology, many kinds of micro/nano-scale materials have been used in the construction of electrochemical biosensors because of their unique and particular properties. Among these catalysts, copper oxide (CuO), as a well known p-type semiconductor, has gained increasing attention not only for its unique properties but also for its applications in many fields such as gas sensors, photocatalyst and electrochemistry sensors. Continuing our previous investigations on transition-metal oxide including cuprous oxide and α-Fe2O3 modified electrode, in the present paper we examine the electrochemical and electrocatalytical behavior of flower like copper oxide modified glass carbon electrodes (CuO/GCE).

RESULTS

Flower like copper oxide (CuO) composed of many nanoflake was synthesized by a simple hydrothermal reaction and characterized using field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). CuO modified glass carbon electrode (CuO/GCE) was fabricated and characterized electrochemically. A highly sensitive method for the rapid amperometric detection of hydrogen peroxide (H2O2) and nitrite (NO2-) was reported.

CONCLUSIONS

Due to the large specific surface area and inner characteristic of the flower like CuO, the resulting electrode show excellent electrocatalytic reduction for H2O2 and oxidation of NO2-. Its sensitivity, low detection limit, fast response time and simplicity are satisfactory. Furthermore, this synthetic approach can also be applied for the synthesis of other inorganic oxides with improved performances and they can also be extended to construct other micro/nano-structured functional surfaces.