Synthesis and characterization of LaMnO3 nanocrystals and graphene oxide: fabrication of graphene oxide–LaMnO3 sensor for simultaneous electrochemical determination of hydroquinone and catechol

Abstract

<p><span lang="EN-GB">For the first time, a new method for preparation of graphene oxide-LaMnO<sub>3 </sub>(GO-LaMnO<sub>3</sub>) nanocompositeas a material of electrochemical sensor for simultaneous determination of catechol (CT) and hydroquinone (HQ)<strong> </strong>is developed. LaMnO<sub>3 </sub>nanoparticles have been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX) technique. Due to the excellent catalytic activity, enhanced electrical conductivity and high surface area, the simultaneous determination of HQ and CT with two well-defined peaks has been achieved at the GO-LaMnO<sub>3 </sub>modified electrode. Comparing with unmodified electrodes, the oxidation currents of HQ and CT increased remarkably. Also, the result exhibited a great decrease in anodic overpotential</span><em></em><span lang="EN-GB">resulting in about 150 mV negative shift of potential. The catalytic peak current values are found linearly dependent on the HQ and CT concentrations in the range of 0.5–433.3 and 0.5–460.0 μM with sensitivity of 0.0719 and 0.0712 μA μM<sup>-1</sup>, respectively. The detection limits for HQ and CT are determined as 0.06 and 0.05 μM, respectively.</span></p>

Hydroxyl-Functionalized Covalent Organic Frameworks as High-Performance Supercapacitors

“…Polymers 2022, 14, x FOR PEER REVIEW 8 of 13 humps in CV curves (Figure S21c,d) [48][49][50][51][52]. The apparent peak separations between the waves of oxidation and reduction of both COFs were quite small, indicating a rapid electron transfer between the GC electrode and the dihydroxynaphthalene units in the COFs [53,54].…”

“…Figure 5A,B and Figure S20 reveal the CV curves of the hydroxyl-functionalized COFs in the potential window from −0.8 to +0.2 V which were recorded at various rates ranging from 5 to 200 mV s −1 . The CV curves of TAPT-2,3-NA(OH) 2 and TAPT-2,6-NA(OH) 2 COFs showed quasi-rectangular shapes with small humps around −0.44 V for the TAPT-2,3-NA(OH) 2 and around −0.39 V for the TAPT-2,6-NA(OH) 2 COFs (Figure S21a,b), suggesting that the capacitive responses were originated mainly from the EDL capacitance and minor from pseudo-capacitance [48][49][50][51][52]. The redox reactions of 2,3-dihydroxynaphthalene or 2,6-dihydroxynaphthalene on the COF surfaces and/or the N-heteroatom functionalities of the substance can be responsible for the formation of small humps in CV curves (Figure S21c,d) [48][49][50][51][52].…”

“…The CV curves of TAPT-2,3-NA(OH) 2 and TAPT-2,6-NA(OH) 2 COFs showed quasi-rectangular shapes with small humps around −0.44 V for the TAPT-2,3-NA(OH) 2 and around −0.39 V for the TAPT-2,6-NA(OH) 2 COFs (Figure S21a,b), suggesting that the capacitive responses were originated mainly from the EDL capacitance and minor from pseudo-capacitance [48][49][50][51][52]. The redox reactions of 2,3-dihydroxynaphthalene or 2,6-dihydroxynaphthalene on the COF surfaces and/or the N-heteroatom functionalities of the substance can be responsible for the formation of small humps in CV curves (Figure S21c,d) [48][49][50][51][52]. The apparent peak separations between the waves of oxidation and reduction of both COFs were quite small, indicating a rapid electron transfer between the GC electrode and the dihydroxynaphthalene units in the COFs [53,54].…”

Electrochemical DNA-nano biosensor for the detection of Goserelin as anticancer drug using modified pencil graphite electrode

“…Electrochemical methods have attracted a lot of interest in this arena because of their excellent sensitivity, selectivity, and capacity to reduce interferences (14)(15)(16)(17). Because the electrochemical oxidation of the analyte often entails a significant overpotential at the surface of the bare electrodes, additional oxidizable substances frequently cause interference with the analyte's identification (18)(19)(20)(21)(22)(23). Chemically modified electrodes (CMEs) have gained significant attention because of their ability to transport electrons quickly, reduce overpotential with little surface fouling, and lower the overpotential of oxidizing species in order to avoid these interferences (24)(25)(26)(27)(28).…”

Síntesis y caracterización de titanato de calcio (CaTiO3) como potencial sensor electroquímico de contaminantes orgánicos en solución acuosa

“…Igualmente, se pueden identificar trabajos que han permitido el avance del estudio de las perovskitas dopados con metales de transición utilizadas como sensores. Akbari et al (2019) describieron la preparación de un nuevo sensor modificado con óxido de grafeno-LaMnO3 para la determinación de hidroquinona y catecol mediante la técnica de voltamperometría cíclica, mostraron un excelente desempeño en la determinación simultánea de los contaminantes [28]. Así como el trabajo Park et al (2020) quienes establecieron un método para el desarrollo de un sensor colorimétrico fácil y portátil basado en celulosa combinándolo con CsPbBr3 para la detección a simple vista de iones de yodo y cloro [29].…”