Nanocomposites with ZrO2@S-Doped g-C3N4 as an Enhanced Binder-Free Sensor: Synthesis and Characterization

Nigussie Alebachew; H C Ananda Murthy; Bedasa Abdisa Gonfa; Karel G von Eschwege; Ernst H G Langner; Elizabeth Coetsee; Taye B Demissie

doi:10.1021/acsomega.2c08174

Nanocomposites with ZrO₂@S-Doped g-C₃N₄ as an Enhanced Binder-Free Sensor: Synthesis and Characterization

ACS Omega. 2023 Apr 3;8(15):13775-13790. doi: 10.1021/acsomega.2c08174. eCollection 2023 Apr 18.

Authors

Nigussie Alebachew¹, H C Ananda Murthy^{1

2}, Bedasa Abdisa Gonfa¹, Karel G von Eschwege³, Ernst H G Langner³, Elizabeth Coetsee⁴, Taye B Demissie⁵

Affiliations

¹ Department of Applied Chemistry, School of Applied Natural Science, Adama Science and Technology University, P.O. Box 1888, Adama 251, Ethiopia.
² Department of Prosthodontics, Saveetha Dental College & Hospital, Saveetha Institute of Medical and Technical Science (SIMATS), Saveetha University, Chennai 600077, Tamil Nadu, India.
³ Department of Chemistry, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa.
⁴ Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9310, South Africa.
⁵ Department of Chemistry, University of Botswana, P.bag UB 00704 Gaborone, Botswana.

Abstract

This study describes new electrocatalyst materials that can detect and reduce environmental pollutants. The synthesis and characterization of semiconductor nanocomposites (NCs) made from active ZrO₂@S-doped g-C₃N₄ is presented. Electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) measurements were used to examine electron transfer characteristics of the synthesized samples. Using X-ray diffraction (XRD) and high-resolution scanning electron microscopy (HR-SEM) techniques, inclusion of monoclinic ZrO₂ on flower-shaped S-doped-g-C₃N₄ was visualized. High-resolution X-ray photoelectron spectroscopy (XPS) revealed successful doping of ZrO₂ into the lattice of S-doped g-C₃N₄. The electron transport mechanism between the electrolyte and the fluorine tin-oxide electrode (FTOE) was enhanced by the synergistic interaction between ZrO₂ and S-doped g-C₃N₄ as co-modifiers. Development of a platform with improved conductivity based on an FTOE modified with ZrO₂@S-doped g-C₃N₄ NCs resulted in an ideal platform for the detection of 4-nitrophenol (4-NP) in water. The electrocatalytic activity of the modified electrode was evaluated through determination of 4-NP by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) under optimum conditions (pH 5). ZrO₂@S-doped g-C₃N₄ (20%)/FTOE exhibited good electrocatalytic activity with a linear range from 10 to 100 μM and a low limit of detection (LOD) of 6.65 μM. Typical p-type semiconductor ZrO₂@S-doped g-C₃N₄ NCs significantly impact the superior detection of 4-NP due to its size, shape, optical properties, specific surface area and effective separation of electron-hole pairs. We conclude that the superior electrochemical sensor behavior of the ZrO₂@S-doped g-C₃N₄ (20%)/FTOE surfaces results from the synergistic interaction between S-doped g-C₃N₄ and ZrO₂ surfaces that produce an active NC interface.