Mesoporous Carbon/α-Fe₂O₃ Nanoleaf Composites for Disposable Nitrite Sensors and Energy Storage Applications

Abstract

In this work, we report a novel hydrothermal synthesis of α-Fe 2 O 3 nanoleaf-incorporated mesoporous carbon-chitosan (α-Fe 2 O 3 @MPC-chit) as a versatile disposable sensor for selective electrochemical detection of nitrite and for supercapacitor applications. The newly synthesized α-Fe 2 O 3 @MPC-chit nanocomposite was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, UV, and Raman spectroscopy. The extensive physicochemical characterization reveals the strong immobilization of α-Fe 2 O 3 nanoleaves within the MPC-chit composite. The electrochemical characterization with cyclic voltammetry and impedance spectroscopy using [Fe(CN) 6 )] 3–/4– as a redox probe concludes good electron conductivity and efficient electron transfer behavior of α-Fe 2 O 3 @MPC-chit. The α-Fe 2 O 3 @MPC-chit modified electrode exhibits excellent electrocatalytic activity toward nitrite oxidation. The amperometric method of nitrite detection showed a linear range of up to 200 μmol L –1 . The current sensitivity and detection limit were found to be 0.913 μA μM –1 and 31 nM cm –2 , respectively. The improved catalytic activity of the proposed electrode was endorsed by the synergistic effect of α-Fe 2 O 3 with the MPC-chit composite. The ability of the proposed electrode was demonstrated by the successful detection of nitrite present in tap water, river water, and industrial samples with extensive recovery values. Furthermore, the α-Fe 2 O 3 @MPC-chit modified stainless-steel electrode showed high-performance supercapacitor application and exhibited a large specific capacitance of 380 F g –1 at 1 A g –1 .

Preparation of Graphene Oxide/La2Ti2O7 Composites with Enhanced Electrochemical Performances for Supercapacitors

“…Many transition-metal oxides (TMOs) have been studied for their good pseudocapacitance properties. It has been reported that the electrical performance of other carbon materials was enhanced by doping TMOs, such as mesoporous carbon, , carbon nanofibers, ,, and carbon nanosheets. , It is feasible to increase the energy storage properties by the combined use of TMOs and graphene. ,, Various groups have reported on the combined use of graphene and TMOs to overcome the drawbacks in the electrochemical properties.…”

Hierarchical Fe2O3/Na2WO4 Nanofibers Supported on Conductive Carbon Cloth as a High-Performance Supercapacitor

“…At the FT-IR spectrum of calcined Fe 2 O 3 /Na 2 WO 4 nanofibers, the loss of the corresponding CN and NH functional group bands has been shown to confirm successful calcination of PVP-Fe­(NO 3 ) 3 /Na 2 WO 4 nanofibers. The FT-IR spectrum of the CC-Fe 2 O 3 /Na 2 WO 4 NF electrode successfully adsorbed the Fe 2 O 3 /Na 2 WO 4 nanofiber layers by the tensile vibrational bands of these binary metal oxides which are shown in the range between 591 and 440 cm –1 (Figure a). , …”

“…The FT-IR spectrum of the 2a). 38,39 The prepared samples were further characterized by XRD to identify the purity and crystallite phase (Figure 2b). The XRD pattern of PVP-Fe(NO 3 ) 3 /Na 2 WO 4 NFs showed an amorphous peak at 20.1°assigned to the PVP structure.…”

A New Anderson‐Type Polyoxometalate‐Based Metal‐Organic Complex for Multi‐Functional Electrochemical Application

“…The results indicate that 1-CPE has the electrocatalytic activity for reducing KBrO 3 and NO 2 À . Accurate and rapid detection of nitrite in ecological environment by electrochemical technology is very important [41] due to the harmness to environment and human health brought by nitrite. Based on the good electrocatalytic behavior of 1-CPE, current analysis i-t technology was used to detect nitrite under the optimum conditions.…”