Morphology of hydrothermally synthesized ZnO nanoparticles tethered to carbon nanotubes affects electrocatalytic activity for H2O2 detection

Abstract

We describe the synthesis of zinc oxide (ZnO) nanoparticles and demonstrate their attachment to multiwalled carbon tubes, resulting in a composite with a unique synergistic effect. Morphology and size of ZnO nanostructures were controlled using hydrothermal synthesis, varying the hydrothermal treatment temperature, prior to attachment to carboxylic acid functionalized multi-walled carbon nanotubes for sensing applications. A strong dependence of electrocatalytic activity on nanosized ZnO shape was shown. High activity for H2O2 reduction was achieved when nanocomposite precursors with a roughly semi-spherical morphology (no needle-like particles present) formed at 90 °C. A 2.4-fold increase in cyclic voltammetry current accompanied by decrease in overpotential from the composites made from the nanosized, needle-like-free ZnO shapes was observed as compared to those composites produced from needle-like shaped ZnO. Electrocatalytic activity varied with pH, maximizing at pH 7.4. A stable, linear response for H2O2 concentrations was observed in the 1–20 mM concentration range.

A Zinc Oxide Carbon Nanotube Based Sensor for In Situ Monitoring of Hydrogen Peroxide in Swimming Pools

“…Sensitivity for H 2 O 2 was maximized by eliminating ZnO needle‐like structures using hydrothermally synthesizing the ZnO nanoparticles (NPs) prior to attachment to the COOH‐MWNTs, described elsewhere 20. In this present study, we demonstrate, for the first time, the effective use of a green, non‐precious metal based, enzyme‐free, and non‐silicon semiconductor technology based composite for dynamic amperometric measurements of H 2 O 2 in swimming pool media.…”

“…Our H 2 O 2 composite for this application is unique in that it does not involve the incorporation of precious metals (contributing to high cost), and is free of surfactants (leading to unwanted byproducts) and enzymes (resulting in instability). While Prussian blue (PB)‐CNT composites have been touted as promising H 2 O 2 sensing materials 23–26, none of these materials to date have shown selective, quantitative measurement for both H 2 O 2 and uric acid (a noteworthy contaminant in swimming pool environments) as previously demonstrated by the ZnO‐MWNT composite 20 used in this study.…”

“…Zinc oxide (ZnO) is an n‐type semiconductor material. ZnO, due to its high conductivity, exciton binding energy (60 meV), wide band gap (3.37 eV) and high breakdown strength, is an ideal candidate for a sensing material 20–22.…”

A nanoporous MgO based nonenzymatic electrochemical sensor for rapid screening of hydrogen peroxide in milk

“…9 Nanometer materials, such as precious metal nanoparticles, carbon materials, transition metallic nanoparticles, transition metal oxides and alkaline earth metal oxides, [15][16][17][18][19][20] are most important choice for building the nonenzymatic sensor to solve the problems of the low long-term operational stability and poor reproducibility. 9 Nanometer materials, such as precious metal nanoparticles, carbon materials, transition metallic nanoparticles, transition metal oxides and alkaline earth metal oxides, [15][16][17][18][19][20] are most important choice for building the nonenzymatic sensor to solve the problems of the low long-term operational stability and poor reproducibility.…”

Rapid synthesis of Co, Ni co-doped ZnO nanoparticles: Optical and electrochemical properties

“…Recent reviews have highlighted the potential electrochemical applications of ZnO attached to carbon nanotubes [7,8]. Electrochemical sensors using a combination of ZnO nanoparticles with carbon nanotubes presented improved characteristics, such as higher selectivity and sensitivity owing to the electrocatalytic properties of the resulting composite material, which has been demonstrated in the sensing of hydrazine [9], hydrogen peroxide [10], hydroxilamine [11], xanthine [12], and p-nitrophenol [13]. Nevertheless, few studies have been devoted to investigating the effect of doping ZnO attached to carbon nanotubes on electrochemical sensing performance.…”