Nanoporous Cobalt Hexacyanoferrate Nanospheres for Screen-Printed H₂O₂ Sensors

Abstract

The development of highly sensitive hydrogen peroxide (H 2 O 2 ) sensors of low cost with high stability is essential because of the significance of H 2 O 2 in biological systems and its practical applications in different fields. The present work concerns the development of a highly sensitive flexible screen-printed amperometric H 2 O 2 sensor. Hexacyanoferrates are known to be excellent sensing materials for nonenzymatic electrochemical sensing of hydrogen peroxide (H 2 O 2 ), but they have certain limitations such as instability and low sensitivity. We have developed a method for the synthesis of porous cobalt hexacyanoferrate nanospheres (CoHCF-NSp's) (<50 nm size) by using EDTA as a chelating agent. Increasing the EDTA concentration and heating the EDTA complex at 60 °C turned the microspheres of CoHCF into porous nanospheres due to the rapid nucleation of CoHCF. The synthesized porous nanospheres with high specific surface area and pore volume led to much improved electrochemical properties. The porous CoHCF-NSp's were used for the fabrication of a highly sensitive H 2 O 2 sensor. Amperometric characterization of screenprinted sensors prepared using the CoHCF nanospheres showed a linear response in the detection range of 0.002−1.13 mM with a detection limit of 2.1 μM. The sensitivity of the sensor was found to be 329 μA•mM −1 •cm −2 , which is much better than the sensitivities of most of the previously reported H 2 O 2 sensors. The fabricated sensors were found to be stable at ambient temperature. The sensors were found to be effective in the testing of real samples (lake water and flavored drink).

Electrochemical Detection of Tyrosinase in Cell Lysates at Functionalized Nanochannels via Amplifying of Ionic Current Response

“…The binding of Fe 2+ was further verified through XPS analysis. Two clear peaks were observed at 708.1 eV and 721.3 eV at ANC/APTMS/Try after reacting with Fe 2+ , which are attributed to Fe 2p 3/2 and Fe 2p 1/2 (Figure 3B) [45–46]. By contrast, no peak was observed at ANC/APTMS/Try in PBS solution (pH 7.4) in absence of Fe 2+ .…”

BiVO4 Microparticles Decorated with Cu@Au Core-Shell Nanostructures for Photocatalytic H2O2 Production

“…H 2 O 2 , a green and benign oxidant, is widely applied in many areas such as chemical synthesis, environmental remediation, and industrial production. − At present, hydrogen peroxide is synthesized by an industrial anthraquinone method; however, this method involves many sequential steps, thus consuming a vast amount of energy and resources. − Consequently, massive efforts have been devoted to development of eco-friendly routes toward green H 2 O 2 production such as the direct synthesis from H 2 and O 2 , electrochemical synthesis, and photocatalytic H 2 O 2 production. − Among them, photocatalytic H 2 O 2 production utilizing sunlight as the energy input is one of the most promising pathways. , Given that photocatalysis mainly relies on the use of photocatalytic materials, thus, exploiting effective photocatalysts is of vital importance to produce H 2 O 2 …”

EDTA derived graphene supported porous cobalt hexacyanoferrate nanospheres as a highly electroactive nanocomposite for hydrogen peroxide sensing

“…The synthesis of P-CoHCF-NSPs was followed from our previous work. 14 Heating the EDTA complex increases the nucleation rate of CoHCF crystals due to the quick release of cobalt ions from the EDTA–cobalt ion complex. As a result of the rapid nucleation, EDTA residues are incorporated in the CoHCF nanospheres, contributing to the porous structure of CoHCF nanospheres.…”

“…8,9 Most nonenzymatic electrochemical sensors usually work either on electrochemical oxidation or electrochemical reduction by a chemically modified electrode material. Electrode materials like noble metal nanoparticles, 10 metal oxides, 11,12 hexacyanoferrates, [13][14][15] and carbon-based materials like quantum dots, 16 nano onions, 17 nanotubes, 18 graphene, 7,19,54 and their respective composites 20,21 were used for nonenzymatic H 2 O 2 determination. Among these materials, graphene and graphene composites have been found to be more promising for H 2 O 2 electrochemical sensing due to their large specific surface area, highly conductive nature, biocompatibility, and stable wide potential window.…”

“…So, efforts have been made to increase the H 2 O 2 oxidation capability of TMHCFs by synthesizing different nanostructures. 14 As a result, even though the sensitivity of TMHCF-based H 2 O 2 sensors has improved, their oxidation capability has not shown significant improvements due to their lower electrical conductivity. As reported by other researchers, the use of graphene may address the issue of poor conductivity of the sensing material (TMHCF).…”