Vol.:(0123456789)
Environmental Science and Pollution Research
https://doi.org/10.1007/s11356-024-34703-x
RESEARCH ARTICLE
Bifunctional properties of Ag/α‑Fe
2
O
3
/rGO nanocomposite
for supercapacitor and electrochemical nitrate sensing using
tetradodecyl ammonium nitrate as ion‑selective membrane
Percy J. Sephra
1
· Tharini Chandrapagasam
1
· Abhay Sachdev
2,4
· Manikandan Esakkimuthu
3
Received: 16 February 2024 / Accepted: 9 August 2024
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024
Abstract
Noble metal nanoparticles incorporated in hybrid nanocomposites are considered as promising candidates for electrochemi-
cal applications owing to their physicochemical properties. In this work, we demonstrated the preparation of Fe
2
O
3
/rGO
nanocomposite by hydrothermal method, followed by in situ Ag binding synthesis for the fabrication of hybrid nanocom-
posite (Ag/α-Fe
2
O
3
/rGO). The crystallographic structure of the hybrid nanocomposite is examined by X-ray diffraction
(XRD) analysis which confirms the characteristics of Ag, Fe
2
O
3
, and rGO. The microscopic studies and energy-dispersive
X-ray analysis (EDS) spectra confirmed the presence and formation of hybrid nanostructures. Raman analysis results fur-
ther corroborate the formation of composite with significant D and G bands in Fe
2
O
3
/rGO and Ag/α-Fe
2
O
3
/rGO samples,
which follow XRD results. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) studies were carried out to
analyze the faradaic capacitor behavior. A specific capacitance of 209.09 F/g was observed by GCD studies for Ag/α-Fe
2
O
3
/
rGO composites at a current density of 1 A/g, which exhibited good capacitance retention of 94% for 5000 cycles at 7 A/g.
Furthermore, the Ag/α-Fe
2
O
3
/rGO electrode was used for the electrochemical detection of nitrate ions in soil by utilizing an
ion-selective membrane over the surface of the Ag/α-Fe
2
O
3
/rGO electrode. The fabricated nanocomposite electrode showed
a significant change in the peak current values with the concentration of nitrate in a linear range from 10 to 450 μM with the
sensitivity to be calculated 1.426 μA μM
−1
cm
−2
and limit of detection (LOD) calculated to be 0.18 μM. The reproducibility
and interference studies showed a promising result to be utilized for detecting nitrate ions in soil and in real-time applications.
Keywords Bifunctional · Electrochemical studies · Supercapacitor · Nitrate detection · Soil sensing
Introduction
The increasing demand for effective energy storage systems
owing to the increased popularity of motor vehicles and
portable electronic devices resulting in the development
of sophisticated batteries and high-performing capacitors
research (Jalal et al. 2021; Şahin et al. 2022). Supercapaci-
tors, sometimes referred to as electrochemical or ultracapaci-
tors, are distinguished by their capacity to provide signifi-
cant energy delivery quickly, which makes them essential
for applications requiring power spikes (Xiong et al. 2023)
(González et al. 2016). Transition metal oxides, whose
charge storage is mostly fuelled by pseudocapacitance, have
been investigated as possible supercapacitor electrode mate-
rials. Due to redox transitions that deeply penetrate its bulk
structure, the ruthenium oxide (RuO
2
) exhibits high capaci-
tance; nonetheless, Ru’s high cost makes it difficult for the
material to be commercially viable. Thus, the development
Responsible Editor: Angeles Blanco
* Tharini Chandrapagasam
tharini@crescent.education
1
Department of Electronics and Communication Engineering,
B. S. Abdur Rahman Crescent Institute of Science &
Technology, Chennai 600048, India
2
Academy of Scientific and Innovative Research (AcSIR),
Ghaziabad 201002, India
3
Centre for Innovation and Product Development, Vellore
Institute of Technology (Chennai Campus), Chennai 600127,
India
4
Materials Science & Sensor Application Division,
CSIR-Central Scientific Instruments Organization
(CSIR-CSIO), Chandigarh 160030, India