Electrochemical sensor and photocatalytic studies of ferrite nanoparticle using different fuels via green approach

Abstract

The solution combustion process and environmentally acceptable green fuels, including plant root extracts from Flacortia indica and Aloe vera, were used to make a nanostructured nickel ferrite (NiFe₂O₄). We used X-ray diffraction (XRD) to find the crystallinity of the produced ferrite nanoparticles, Field Emission scanning electron microscopy (FE-SEM) to examine the surfaces, and energy dispersive X-ray diffraction (EDAX) to find the elements. The NiFe₂O₄ sample was subjected to electrochemical testing, which included electrostatic charge and discharge (GCD) experiments with electrodes submerged in a 0.1 M HCl electrolyte and measurements of AC impedance. The sample was used to build chemical sensors for arsenic trioxide and mercuric acetate. Thanks to their capacity to be magnetically retrieved, aloe vera-mediated combustion of NiFe₂O₄ NPs degraded 98.4 percent of the AR-88 dye after 90 min, whereas combustion of plant root extract under UV light degraded 84.4 percent. The increased emphasis on research that this comparison study sparked led to the production of high-quality, repeatable materials made of bio-composite reagents that are non-toxic and environmentally friendly.

Graphical Abstract

Keywords:

• Ferrite
• combustion
• electrochemical
• sensor
• photocatalytic

1. Introduction

Emerging nanomaterials and related phenomena may be the focus of future nano-science research. In recent years, magnetic nano-materials have attracted a lot of attention due to the intriguing uses they have (Taghavi Fardood et al. 2023, 2018a, 2022; Moradnia et al. 2020; Taghavi Fardood et al. 2018b). The magnetic characteristics of spinel ferrites, which are described by the formula MFe₂O₄ (where M is an element such as Zn, Ni, Mn, Co, etc.), make them extremely adaptable in a wide range of applications (Taghavi Fardood et al. 2023, 2018a, 2022; Moradnia et al. 2020; Taghavi Fardood et al. 2018b). Spinel ferrites are essential in many applications, including data storage, magneto-optical recording, antennas, humidity sensors, energy storage devices, inductors, microwave devices, and magnetic sensing (Dhanda et al. 2023; Raghavendra et al. 2021; Manjunatha et al. 2023). Their extraordinary chemical, optical, electrical, and magnetic characteristics render them indispensable in these domains. Additionally, ferrofluids for targeted therapies, medical diagnostics, cancer therapy, hyperthermia treatment, drug delivery systems, MRI (Magnetic Resonance Imaging), and other medical applications have come to rely on magnetic nanoparticles, particularly ferrite nanoparticles (Raghavendra et al. 2021; Mylarappa et al. 2022).

The precise targeting and colloidal stability of nanostructures are essential for these applications, and nanoparticles’ sensitivity, influenced by their surface area-to-volume ratio, plays a crucial role (Basavaraju et al. 2021). Beyond medical and technological applications, ferrite nanoparticles have also demonstrated effectiveness in environmental applications, particularly in wastewater treatment and dye degradation (Surendra et al. 2023; Vasudha et al. 2021; Raghavendra et al. 2024; Al Asian, Olya, and Mahmoodi 2015; Mahmoodi et al. 2019). NiFe₂O₄ nanoparticles (NPs) are important because of their many uses. Due to their excellent permeability at high frequencies, electrical resistivity, and chemical and mechanical stability, they are widely used in electronics (Ishino and Narumiya 1987; Manjunatha 2022; Charithra and Manjunatha 2021; Manjunatha et al. 2020; Hareesha and Manjunatha 2020). These ferrites also exhibit interesting electrochemical properties and photocatalytic degradation that make them suitable for various applications due to their unique combination of properties, including high conductivity, catalytic activity, and stability.

These ferrites can be synthesised using several techniques like chemical methods, including combustion, coprecipitation, sol-gel, mechanical alloying and precipitation for the fabrication of stoichiometric and chemically pure spinel ferrite nanoparticles (Manjunatha 2022; Charithra and Manjunatha 2021; Manjunatha et al. 2020; Hareesha and Manjunatha 2020; Manjunatha 2020; Verma, Goel, and Mendiratta 2000; Chen and He 2001). However, the combustion process is commonly utilised to generate nanoparticles with specified properties for diverse purposes. Moreover, the process is relatively simple, scalable, and cost-effective, making it suitable for large-scale production. In summary, the combustion method for synthesising ferrite nanoparticles can align with green synthesis principles by minimising energy consumption, eliminating or reducing the use of harmful solvents, generating minimal waste, using sustainable starting materials, maintaining low toxicity, and offering scalability. Overall, the combustion technique is a versatile method for synthesising nanocrystalline nickel ferrite nanoparticles with specific characteristics tailored for various applications, including catalysis, magnetic storage, biomedical imaging, and environmental remediation.

Ferrites have also been studied as electrocatalysts for various reactions due to their high surface area, good conductivity, and catalytic activity (Chen and Liu 2012; Karakas et al. 2015; Maaz et al. 2009; Sue et al. 2011). They have shown potential in oxygen reduction reactions (ORR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and other important electrochemical processes (Son et al. 2002; Wang et al. 2009; Qu et al. 2007; Can, Fırat, and Özcan 2011). These can be used as electrode materials in supercapacitors due to their high specific surface area, high sensitivity, high capacitance, and excellent electrochemical performance making them promising candidates for energy storage applications, electrochemical sensors for detecting various analytes such as heavy metals, gases, and biomolecules. Continued research in this area is essential for further understanding and optimising their performance for practical use in various electrochemical devices and systems. According to the literature, developing the solution combustion process to produce ferrites from a variety of eco-friendly fuels would be highly beneficial. In this work, naturally occurring, eco-friendly, and easily available green fuels such as aloe vera and plant root extract are used to synthesise and characterise NiFe₂O₄ nanoparticles via green approach. Different spectral characterisation methods, including XRD, EDAX, SEM, CV, sensor and photocatalytic studies, were used to confirm the synthesised NiFe₂O₄.

2. Experimental

2.1. Materials and method

In this work, all the chemicals were purchased from Merck as indicated in the following Table 1.

Table 1. List of chemicals, specifications and suppliers used.

Name	Molecular formula	Molar mass and density	Suppliers
Nickel nitrate	Ni (NO3)2.6H2O	Molar mass: 290.79 Density: 2.05 g/cm^3	Merck
Ferric nitrate	Fe (NO3)3⋅9H2O	Molar mass: 404 g/mol 1.68 g/cm^3	Merck
Aloe vera	C16H13NO3	Molar mass: 267.279 g/mol Density: 1.2 ± 0.1 g/cm^3	Karnataka, India
Licorice plant root extract	C42H62O16Zn	Molar mass: 888.3 g/mol	Natural plant

2.2. Experimental procedure

2.2.1. Extraction of Aloe vera gel

The extract appears in the gel that is found in the canter of aloe vera leaves. The outer green coat of aloe vera was peeled (sliced) off in order to obtain the gel. The inner part of the gel, which was firmly crushed and ground to a thin, homogenous consistency, was used to create the jelly used in the synthesis. Aloe vera gel was employed as a sustainable substitute to fuel the NPs’ synthesis.

2.2.2. Synthesis NiFe₂O₄ by simple solution combustion method

NiFe₂O₄ NPs can be produced by dissolving 1.45 g of nickel nitrate and 2.415 g of ferric nitrate in distilled water in a crucible. 1.8 ml of aloe vera gel or 1.08 g of plant root extract are the next ingredients to be added. The crucible was put in a heated muffle furnace to maintain its temperature of 750 °C. When the combustion process is complete, the final product can be ground into a fine powder using a clean mortar and pestle. Utilising the traditional calculation approach, the stoichiometric compositions of aloe vera, nickel nitrate, and plant root extracts should be ascertained. A schematic representation of the aloe vera solution combustion method-based nickel ferrite synthesis process is presented in Figure 1.

Figure 1. Schematic representation for the preparation of NiFe₂O₄ by combustion method.

2.2.3. Characterisation

A nanocomposite of NiFe₂O₄-aloe vera and NiFe₂O₄-root extract was studied using an XRD Maxima-7000 instrument from Shimadzu to determine its structural characteristics. A JEOL JSM-5600LV and a SU-1500, HITACHI were used for morphology and EDX analyses of the samples. A UV-Vis absorption spectrum was recorded using an SL 159 ELICO UV-Visible spectrophotometer. Under UV light irradiation, the produced NPs were photocatalytically decoloured with Acid Red-88 (AR-88) dye. A CHI608E potentiostat tri-electrode configuration was utilised to conduct electrochemical activity. The setup included a modified electrode, platinum wire, and Ag/AgCl as the working, counter, reference electrodes, respectively and the electrolyte employed was a 0.1 M HCl solution.

3. Results and discussions

3.1. X-ray diffraction studies

The XRD (X-Ray Diffraction) pattern of synthesised NiFe₂O₄ NPs by solution combustion method as shown in Figure 2(a,b). The peaks at {220},{311},{222},{400},{511} and {440} related to the 2θ values of 30.4°, 36.7°, 37.8°, 43.5°, 57.5° and 63.4° correspondingly. The sample can be indexed as inverse spinel NiFe₂O₄ with face centred cubic (fcc) structure corresponded to the standard reference (JCPDS Card No.10–0325) (Yousefi, Amiri, and Salavati-Niasari 2019). A secondary phase, haematite (𝛼-Fe₂O₃) was observed at 2θ values 33.4°, 40.9°, 49.6° (JCPDS Card No: 79–0007) (Karcıoğlu Karakaş 2022). Maintaining the ideal temperature and proper stochiometric ratios of both oxidants and fuels should reduce the secondary phase. Table 2 reveals that the average crystalline size of the produced NiFe₂O₄ shows a range from 21.7 to 23.6 nm for NiFe₂O₄-aloe vera and NiFe₂O₄-root extract, respectively, in accordance to the Scherrer formula. (1) $$D=\frac{k\lambda }{\beta \mathrm{\text{cos}}\theta }$$(1)

Figure 2. XRD pattern of (a) NiFe₂O₄-aloe vera; (b) NiFe₂O₄-root extract.

Table 2. Crystalline size and structural constraints of NiFe₂O₄ nanoparticles.

Sample	Crystalline size (nm)	Strain (ε) $x{10}^{-3}$	Stacking fault (SF)	Dislocation density (δ) (${10}^5 \mathit{\text{lin}} m^{-2})$
NiFe2O4-aloe vera	21.7	1.70	0.379	2.1
NiFe2O4-root extract	23.6	1.52	0.381	1.7

where k – Scherrer constant, λ – wave length, β – FWHM (Fullwidth at half-maximum) and θ – Bragg’s angle (Taghavi Fardood et al. 2019; Moradnia et al. 2020).

3.2. Field emission scanning electron microscopy (FE-SEM) studies

For examining the morphological characteristics of synthetic materials, FE-SEM is one of the best analytical techniques. By using FE-SEM testing, we can easily get images at both high and low magnification. High- and low-magnification images of NiFe2O4 nanoparticles are shown in Figure 3(a,b), correspondingly. Nanoparticle accumulation could be drastically reduced by raising the ultrasonic intensity (M. S. Silva et al. 2023; Modak et al. 2009; Gharagozlou 2009; Gedanken 2004). Figure 3(a) shows that the NiFe₂O₄ nanoparticles have a closed-like shape, and Figure 3(b) shows that the particles are distributed evenly.

Figure 3. FE-SEM images of (a) NiFe₂O₄-aloe vera and (b) NiFe₂O₄-root extract.

3.3. Energy dispersive X-ray analysis studies

The results of the analysis of the elemental compositions of the NiFe₂O₄-aloe vera and NiFe₂O₄-root extracts are shown in Figure 4(a) and Figure 4(b), respectively. Elements with mass percentages of 47.17%, 29.48%, and 23.35% for aloe vera and 45.17%, 33.51%, and 21.32% for plant root extract were present in the synthesised sample, respectively. However, quantitative chemical analysis confirmed the sample’s validity, and EDAX did not detect any impurities.

Figure 4. EDAX spectrum of (a) NiFe₂O₄-aloe vera; (b) NiFe₂O₄-root extract.

3.4. Electrochemical studies

3.4.1. CV Analysis

It was determined that the CV research of the electrochemical properties of the NiFe₂O₄-aloe vera and NiFe₂O₄-root extract nanoparticles was carried out, and the results are depicted in Figure 5 and Figure 6, respectively. The potential window range was between −0.3 and +0.4 V and between −0.4 and +0.6 V (Tables 3 and 4) by using 0.1 M HCl as electrolyte. Electrode fabrication required a 30-min gentle grinding in an agate mortar containing NiFe₂O₄ NPs, graphite powder, and silicon oil in a weight ratio of 15:70:15 (Kumar et al. 2019). When compared to NiFe₂O₄-root extract, NiFe₂O₄-aloe vera had a greater degree of reversibility and possessed a better proton diffusion coefficient in the CV test. As can be seen from the enhanced D value in Figure 7, the electrochemical activity of NiFe₂O₄-aloe vera is significantly more effective than that of NiFe₂O₄-root extract. In the CV of NiFe₂O₄ nanoparticles, the oxidation and reduction peaks are brought about by the transformation of Ni to Ni²⁺ and Fe²⁺ to Fe³⁺, respectively. There was an increase in the scan rate from 0.01 to 0.05 mV/s in each of the samples. With each scan rate, the area of the curves in the CV profiles increased. This is because the two sample electrodes undergo a rapid redox kinetic process (Ravikumar et al. 2018).

Figure 5. CV of NiFe₂O₄-alovera electrode.

Figure 6. CV of NiFe₂O₄-root extract electrode.

Figure 7. Proton deficient coefficient and linear fitting of (a) NiFe₂O₄-aloe vera and (b) NiFe₂O₄-root extract electrode.

Table 3. Reversibility and proton deficient coefficient of NiFe₂O₄-aloe vera nanoparticle.

Scan rate (mV)	${\mathit{\text{ip}}}_c\times {10}^{-4}$	${\mathit{\text{ip}}}_a\times {10}^{-4}$	Reversibility (ER) $\times {10}^{-4}$	Diffusion co-efficient (D)
10	−1.12	1.36	2.48	7.05 X 10^−6
20	−1.39	1.96	3.35
30	−1.54	2.93	4.47
40	−1.65	3.56	5.21
50	−1.76	3.99	5.75

Table 4. Reversibility and proton deficient coefficient of NiFe₂O₄ root extract nanoparticle.

Scan rate (mV)	${\mathit{\text{ip}}}_c\times {10}^{-5}$	${\mathit{\text{ip}}}_a\times {10}^{-5}$	Reversibility (ER) $\times {10}^{-5}$	Diffusion co-efficient (D)
10	−0.09	0.45	0.54	1.533 X 10^−^5
20	−1.85	1.71	3.56
30	−2.46	3.18	6.04
40	−2.86	4.84	7.70
50	−3.39	6.44	9.83

3.5. Electrochemical impedance spectral analysis (EIS)

With a three-electrode setup in 0.1 M HCl and a frequency range of 1 MHz to 100 MHz, we compared the EIS of the NiFe₂O₄ electrode to that of Ag/AgCl. Figure 8 shows the AC impedance of the NiFe₂O₄-aloe vera electrode and Figure 9 shows the AC impedance of the NiFe₂O₄-root extract electrode. The capacitive properties are related to the imaginary component Zimg (Z''), while the ohmic properties are revealed by the real component Zreal (Z'). In comparison to more streamlined shapes, the resistance to charge transfer is usually higher in rigid semicircles. According to the EIS data, the electrical interface conductivity is improved by using the NiFe₂O₄-aloe vera electrode in 0.1 M HCl as opposed to the control electrodes, which have a lower charge-transfer resistance (Rct). Because of this, they are an excellent material to use when building electrochemical sensors.

Figure 8. Nyquist plots of NiFe₂O₄-aloe vera electrode vs. Ag/AgCl electrode.

Figure 9. Nyquist plots of NiFe₂O₄-root extract electrode vs. Ag/AgCl electrode.

3.6. Electrochemical sensor studies

By employing the NiFe₂O₄ electrode’s CV measurement, arsenic trioxide was successfully detected. As seen in Figure 10, the NiFe₂O₄-generated carbon paste electrode can detect arsenic trioxide concentrations ranging from 1–3 mM in an acidic medium (0.1 M HCl). Table 5 shows that there is a noticeable shift in the oxidation peak, which falls within the range of 0.32 to 0.51 V, confirming this. Figure 11 shows that the peak of the rapid oxidation potential increased from 0.38 to 0.15 V when mercuric acetate was utilised as a chemical sensor, and Table 6 shows that the peak of the reduction potential increased from 0.08 to 0.10 V. That the chemical sensor’s sensing capabilities were enhanced is evident from this.

Figure 10. CV response for the NiFe₂O₄ root extract electrode at 0.1 M HCl of sensor arsenic trioxide.

Figure 11. CV response for the NiFe₂O₄ extract electrode at 0.1 M HCl of sensor mercuric acetate.

Table 5. Redox reaction values of NiFe₂O₄ extract using arsenic trioxide sensor.

Concentration	${\mathit{\text{ip}}}_c\times {10}^{-4}$	${\mathit{\text{ip}}}_a\times {10}^{-4}$	Reversibility $\times {10}^{-4}$	Potential (V)
Without sensor	−0.98	0.45	1.43	0.32 to 0.51
0.001	−2.93	1.24	4.17
0.002	−4.58	2.34	6.92
0.003	−5.98	3.50	9.48

Table 6. Redox reaction values of NiFe₂O₄ extract using mercuric acetate sensor.

Concentration	${\mathit{\text{ip}}}_c$	${\mathit{\text{ip}}}_a$	Reversibility (ER)	Potential (V)
Without sensor	−0.0369	0.0265	0.0634	Anodic = −0.381 to −0.153 Cathodic = −0.081 to 0.105
0.001	−0.0335	0.0244	0.0579
0.002	−0.0316	0.0239	0.0555
0.003	−0.0313	0.0238	0.0551
0.004	−0.0309	0.0230	0.0539

3.7. Band gap analysis

The optical properties of the synthesised NiFe₂O₄ from aloe vera and Root extract methods investigated using UV–Visible Diffuse Reflectance spectrophotometric technique as shown in Figure 12. the energy band gap data of synthesised NiFe₂O₄ nanoparticles were calculated by using the Kubelka-Munk equation: F(R) = (1−R)²/2R, with R representing % of reflected light (Moradnia et al. 2021; Mohammad Taghi Kiani and Saeid 2023; Meenakshi et al. 2023). The optical band gap (Eg) is determined from the observed UV-Visible spectral dependence of the absorption near the absorption edge.

Figure 12. Diffuse reflectance spectra of the synthesised NiFe₂O₄ from aloe vera and root extract methods.

Based on Urbach rule the absorption coefficient (α) is calculated from the optical absorption spectrum. It is known that the absorption coefficient for non-crystalline materials varies with frequency and the relationship between the absorption coefficient (α) and the optical band gap Eg obeys the classical Tauc’s expression. Hence, the observed absorption spectrum is translated in to Tauc’s plot using the equation (Dinamani et al. 2023). For all samples a plot of the product of absorption coefficient (α) and photon energy (αhν)1/2 versus the photon energy hν at room temperature shows a linear behaviour, which can be considered as evidence for the indirect allowed transition. Extrapolation of the linear portion of this curve to a point (αhν) 1/2 = 0 gives the optical band gap Eg. Figure 13 shows the energy band gap of the synthesised NiFe₂O₄ from aloe vera and Root extract methods were found to be 3.53 and 4.56 eV respectively. This result confirms that synthesised NiFe₂O₄ from aloe vera method has low energy band gap than Root extract method showed excellent photocatalytic applications.

Figure 13. Kubelka-Munk plot transformed reflectance spectra of the synthesised NiFe₂O₄ from aloe vera and Root extract methods.

3.8. Photocatalytic activities

Photocatalysis is a light-initiated phenomenon that takes place in the presence of a catalyst. The NiFe₂O₄ NPs samples act as photocatalysts and release superoxide radicals (^⋅O²⁻) when they are exposed to light. This happens because the electrons move from the valence band to the conduction band. At the same time, water molecules on the surface react with holes in the valence band to create hydroxyl radicals (OH). These reactive radicals can dissolve organic contaminants at the photocatalyst surface by adsorbing them (Anandan and Rajendran 2015). The research looked at what UV light does to AR-88 dye when it is mixed with NiFe₂O₄ nanoparticles from plant roots and the aloe vera-mediated combustion process (Figure 14(a–d)). When 30 ppm of AR-88 dye was mixed with 30 mg of NiFe₂O₄ nanoparticles made using the aloe vera-mediated combustion technique and plant roots, the results are shown in Figure 14(a,b). The absorbance of the dye was recorded under UV-visible spectroscopy. As shown in Figure 14(c), NiFe₂O₄ nanoparticles made from the aloe vera method were better at breaking down AR-88 dye under UV light, with a rate of 98.4% after 90 min compared to 84% for the plant root-mediated combustion method. Further, it was observed that the photo-degradation performance of AR-88 dye was 12.6% under dark conditions and 15.5% under photolysis (Figure 14(d)).

Figure 14. Absorbance of AR-88 (30 ppm) in presence of NiFe₂O₄ NPs by (a) aloe vera method; and (b) plant root mediated combustion method under UV-light. (c) Plot of % degradation vs time indicating the AR-88 dye photo-degradation capability (d) plot of % degradation vs no. of cycles of AR-88 dye.

In addition, as demonstrated in Figure 14(d), the recycle performance ability of NiFe₂O₄ NPs on AR-88 dye decoloration was assessed after each cycle under the same conditions for a total of 5 cycles. Figure 15(a) shows the NiFe₂O₄ NPs created using the plant root method and Figure 15(b) shows the NiFe₂O₄ NPs prepared using the aloe vera-mediated combustion method, both of which were subjected to UV radiation for the half-time for AR-88 dye decoloration. Results from the sample preparation process show that the degradation time of NiFe₂O₄ NPs mediated by aloe vera is 48.7 min, much shorter than the degradation period of NiFe₂O₄ NPs helped by plant roots 59.8 min. A linear relationship between log C/Co and k for NiFe₂O₄ NPs generated by plant root and aloe vera-mediated combustion techniques under UV light is shown in Figure 15(c). For NiFe₂O₄ NPs produced utilising plant root and aloe vera-mediated combustion techniques, the measured values of slope k were 0.04756 and 0.0988 min⁻¹, respectively, according to the equation. (2) $$\mathrm{\text{Log}}\mathrm{ }\left(\frac{C}{\mathit{\text{Co}}}\right)=-\mathit{\text{kt}}$$(2) where t is the testing duration, Co and C are the dye concentrations, and k is the first order rate constant.

Figure 15. (a) Half time analysis of AR-88 (30 ppm) in presence of NiFe₂O₄ NPs prepared by a aloe vera method; (b) plant root mediated combustion method under UV-light and (c) the kinetics studies of NiFe₂O₄ NPs.

Dye colours are produced by chromophore groups and azo linkages (–N = N–), which have a maximum absorption at 502 nm due to the photocatalytic breakdown of the n → π* transition in ultraviolet light. The AR-88 solution with catalyst has its UV absorption spectra recorded from 0 to 90 min at room temperature. At room temperature, the beginning of the degradation was indicated by a rise in time and a fall in intensity. During the breakdown of AR-88 dye, the green NiFe₂O₄ NPs demonstrated effective catalytic activity. Using UV-Vis spectrophotometry, the process was monitored at room temperature. In addition to the catalysts, which are green NiFe₂O₄ NPs, there may be other factors that contribute to the rapid degradation of the AR-88 dye, as illustrated in Figure 16. These include an increase in electron production by the reductant, aloe vera, and an efficient transfer of charges towards the dye.

Figure 16. The probable photo-catalytic mechanism for degradation of AR-88 dye for NiFe₂O₄ NPs under UV-light irradiation.

4. Conclusion

In this article, the eco-friendly fuels aloe vera and root extract were combined with NiFe₂O₄ NP using the solution combustion method. It was determined that inverted and FCC NiFe₂O₄ NPs had formed by XRD examination. The NiFe₂O₄-root extract had an average particle size of 23.6 nm, whereas the NiFe₂O₄-aloe vera extract had an average particle size of 21.7 nm. The elemental analysis confirmed that the produced samples actually include Cu, Ni, Fe, and O. When compared to NiFe₂O₄-root extract, electrochemical studies on NiFe₂O₄-aloe vera showed a considerable improvement in proton diffusion rate, reaction reversibility, and electricity transfer. In addition, studies on chemical sensors evaluated how well NiFe₂O₄ measured CV for heavy metal detection, specifically mercuric acetate and arsenic trioxide. In particular, the NiFe₂O₄ carbon paste electrodes’ high peak mobility of oxidation and reduction states makes them very good sensors. Since NiFe₂O₄-aloe vera degrades more quickly than NiFe₂O₄-root extract, it may find usage in a variety of applications. These findings suggest that the synthesised NiFe₂O₄ with aloe vera could be useful in a variety of environmental remediation applications, including electrochemical detection of heavy metals and various biosensors for treating industrial effluent water.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge Department of Science and Technology (DST), New Delhi for the financial support for this research, through DST-DDP Project [DST/TDT/DDP-36/2018, Dated 09/09/2020] [PI: Dr. Nagaswarupa H P and Co-PI: Dr. Shashi Shekhar T R].