Green-synthesised cobalt oxide (Co₃O₄) nanoparticles using aloe-vera latex for their photocatalytic and electrochemical sensor studies

Abstract

The current study aimed to investigate multiple applications of synthesised cobalt oxide (Co₃O₄) nanoparticles (CONPs) via Aloe-Vera latex as green fuel by solution combustion approach. The structural parameters of prepared NPs were confirmed by several spectral methods, such as PXRD study shows the existence of cubic phases and crystalline behaviour of synthesised CONPs. Surface morphology and elemental analysis of prepared sample were illustrated by SEM-EDX and TEM techniques. The optical measurement of CONPs was discussed by UV-Visible absorbance spectral technique using Kubelka–Monk function and its energy band-gap is 1.77 eV. This study explored excellent photo-dye-degradation action (98.8% at 135 min) of synthesised photocatalyst on AR-88 dye (40 ppm) under the effect of irradiation of UV-light. Electrochemical behaviour of achieved CONPs was effectively examined by cyclic voltammetry (CV) and electrochemical impedance methods in 1 M KOH. Further, the excellent sensor performance on paracetamol chemical and glucose bio-molecules was examined using CO carbon paste electrode (COCPE). These analyses were revealed that CONPs is an effective and promising material for electrochemical sensor and photocatalytic studies.

GRAPHICAL ABSTRACT

Keywords:

• Co₃O₄ nanoparticles
• green fuel
• electrochemical sensor
• photocatalytic studies
• amperometry

1. Introduction

The development and remarkable applications of noble metal nanomaterials in recent years have benefitted many fields (Basnet et al. 2018; Ghosh Chaudhuri and Paria 2011; Ghotekar 2019; Sridevi et al. 2023; Vinayagam et al. 2023). These fields include solar cells, space technology, biomedicines, sensors, catalysis, cosmetics, healthcare, fuel cells, electrochemistry, biotechnology, energy devices, agriculture, imagination, food technology, optics and optical devices, pharmaceuticals, textiles, and water treatment. Among metal oxide nanoparticles, Co₃O₄ NPs have attracted a lot of attention because of their low price and great electroactivity. However, being a transition metal, cobalt may exist in a variety of oxidation states (including Co²⁺, Co³⁺, and Co⁴⁺). Because of its spinel crystal structure and several functionalities, Co₃O₄ is an established p-type semiconductor with antiferromagnetic properties (Diallo et al. 2015). Co₃O₄ NPs may be employed as photocatalysts to break down a variety of organic contaminants when exposed to visible light due to their direct optical band gaps of 1.48 and 2.19 eV (Shet et al. 2023).

Oxides of cobalt may be found in a variety of spin states, from low to high to intermediate. Co₃O₄’s physics is appealing from a basic perspective and for spintronic applications because of these spin states. Therefore, Co₃O₄ NPs are widely used in field effect transistors (Shet et al. 2023), energy storage (Shinde et al. 2006), catalysis (Sivachidambaram et al. 2017), anode material in Li-ion rechargeable batteries (Li, Xu, and Chen 2005), electrochromic sensors (Han, Yang, and Liu 2015), solar-cells (Sharma et al. 2015), and photocatalysts (Dewi, Ulizar, and Apriandanu 2019). Because of its high-quality biological applications, Co₃O₄ NPs have been shown to have antimicrobial, anticancer, antioxidant, antifungal, and enzyme-inhibiting characteristics (Anuradha and Raji 2019). Hydrothermal (Manjunatha 2022), Thermal decomposition (Manjunatha et al. 2020), Solution combustion (Shaalan et al. 2016), Microwave assisted (Ahmed et al. 2008), Microemulsion method (Kim et al. 2006), Spray pyrolysis (Askarinejad, Bagherzadeh, and Morsali 2010), Sonochemical (Pal and Chauhan 2010), Co-precipitation (Vikas et al. 2012), Sol gel (He et al. 2004), and solvothermal (Pallavolu et al. 2022) methods are just a few of the physical and chemical methods that have been used to synthesise Co₃O₄ NPs.

However, the aforementioned synthetic approaches have several drawbacks that may have a detrimental effect on the environment (Basnet et al. 2018). These include being expensive, time- and energy-consuming, requiring specialised tools for experimental work, and being unfriendly to the environment (Mahadeva Swamy et al. 2021; Manjunatha 2018; Puspalak et al. 2022). Some greener and more eco-accommodating approaches have been offered as a means of addressing the issue of energy imbalance and hazardous waste. Safer synthetic processes need to be developed and used; ideally, these would be low-cost, simple, non-toxic, clean, and efficient. The necessary Co₃O₄ NPs may be made rapidly, effectively, simply, and cheaply using biological resources like plants. Fabricating NPs from plant-derived materials is a viable alternative to traditional physical and chemical approaches (Ghotekar 2019). Here, we used Aloe Vera latex as a fuel in an effort to create Co₃O₄ NPs in an environmentally friendly manner. Co₃O₄ NPs’ photocatalytic and electrochemical sensor properties were studied.

2. Materials and methods

2.1. Preparation

The combustion technique was used in the production of CONPs utilising the eco-friendly fuel of Aloe Vera latex. The Forest Department of Bangalore University in India, collected the Aloe Vera leaves from the neighbouring agricultural areas. The gel was made by dissolving 5 g of cleaned, chopped Aloe Vera leaves in 10 mL of double-distilled water and agitating the mixture for 30 min. Aloe Vera plant extract fuel was produced using the resulting solution. Because plant extracts include biomolecules with the ability to reduce metal ions, such as proteins, carbohydrates, and coenzymes, their usage as reducing agents has also shown promise. These biomolecules also serve as the produced nanoparticles’ capping and stabilising agents. Compared to microbe-mediated synthesis, plant-mediated synthesis is faster and more scalable. It has also been shown to be effective, affordable, and widely accessible (Danish et al. 2022). Cobalt (II) nitrate hexahydrate (Co(NO₃)₂.6H₂O) (Sigma Aldrich) was mixed with 10 mL of Aloe Vera at the stoichiometric ratio. The mixture was stirred well using a magnetic stirrer for 15 min. Before testing, the mixture was heated to 400 °C in a muffle furnace. When the solution is heated, a clear gel is produced. White foam developed from the gel, and then the foam caught fire. The sample’s rapid combustion filled the room with white powder residue. The whole thing only took around 5 min to finish. The final product was calcined at 500 °C for 3 h so that structural and other analyses could be performed. Figure 1 shows that the pictorial representation of the synthesis of CO NPs.

Figure 1. Pictorial representation of synthesis of CO NPs.

2.2. Photocatalytic analysis

The photo-degradation of AR-88 dye was performed under the effect of UV-light irradiation using synthesised CO NPs. This experimental analysis was conducted by using 40 mg of prepared CO NPs which was treated with 250 ml of AR-88 dye (40 ppm) solution taken in a glass reactor. During the experiment, 5 ml of dye solution was pipetted out at regular intervals until complete decomposition of dye solution and finally adsorption was monitored using UV–Visible spectrophotometer. To check the endurance of synthesised CO NPs, the experiment was repeated using the same photocatalyst after washing and drying with fresh dye.

3. Result and discussions

3.1. PXRD analysis

Figure 2 displays the XRD pattern of CO NPs synthesised by combustion utilising green (Aloe Vera latex) fuel. Powder X-ray diffraction investigation verified the structural characteristics of the produced NPs, demonstrating the presence of cubic phases and the crystalline behaviour of the synthesised CO NPs. The diffraction peaks of CO NPs appearing at 2θ = 19, 32, 37, 45, 59.9, and 66° are corresponds to (111), (220), (311), (222), (400), (511), (440), and (533) planes. When compared to cubic phase on standard JCPDS card number 042-1467 (Mahadeva Swamy et al. 2021), these diffraction peaks of CONPs are a good match. In CONPs, the highest intensity line occurs at 37°, which is in accordance with their increased crystallinity and lattice strain. The Debye-Scherrer formula (Equation 1(1) $$D=\frac{k\lambda }{\beta \cos \theta }$$(1) ) was used to determine that typical crystallite size of CONPs is 36 nm. The lower particle size having larger surface area, which directly corresponds to enhanced photo-catalytic activity and electrochemical studies (Manjunatha 2018; Puspalak et al. 2022). (1) $$D=\frac{k\lambda }{\beta \cos \theta }$$(1)

Figure 2. PXRD spectra of synthesised CO NPs by green combustion method.

3.2. Surface morphology investigations

The structural modification with elemental composition and internal-surface morphology of synthesised CO NPs was examined by SEM-EDX techniques (Figure 3). SEM micro-images of synthesised CO NPs clearly show a non-uniform, similarly cubic, and rod shape with well agglomerations as given in Figure 3(a). These micrographs of CO NPs show characteristics of well agglomerated along with observable voids and pores due to impact of solution combustion method. The confirmation of synthesised CO NPs was proved by its elemental compositions using EDAX analysis (Figure 3(b)).

Figure 3. (a) SEM micrographs and (b) EDAX spectra of CO NPs.

Further, it was extended to confirm the formation of CO NPS via TEM, HRTEM, and SAED investigations. Figures 4(a,b) displays TEM micrographs of CO NPs at different magnification, which is distinctly shows regularly cubic shaped with agglomerated in nature. Correspondingly, the HR-TEM micro-image with considering specific region, it shows d spacing values of 0.245 nm for crystal lattice of (111) plane as depicted in Figure 4(c). The SAED patterns of CONPs showed a major superimposed bright spot-on ring patterns indicating the characteristics of polycrystalline in the nature of nanoparticles (Figure 4(d)).

Figure 4. (a,b) TEM images; (c) HRTEM and (d) SAED investigations.

3.3. Functional group examination

The existence of molecular bonding behaviour for synthesised CONPs was examined through the Fourier Transform Infra-red Spectroscopy (FT-IR) process recorded at wavelength ranges of 4000 and 400 cm⁻¹ (Figure 5). The existence of sharp and broad intensity peak at 3444 cm⁻¹ specifies to stretching vibration of hydroxyl (OH^–) ions that is assigned to the adsorbed H₂O from atmosphere. Additionally, the smaller intensity bands at 1638 and 1385 cm⁻¹ are assigned to asymmetric vibrations of unsaturated carbon-carbon (C = C) or carboxyl (C = O) functional groups. The presence of peak in finger-print region corresponds to metal–oxygen vibration linkages. Thus, bending vibrational peaks of Co-O linkage in CO nanoparticle was found to be 650 and 556 cm⁻¹ (Charithra and Manjunatha 2021; Peng et al. 2017; Tang, Wang, and Chien 2008). Therefore, the appearance of two peaks at lower frequency region confirms its characteristic of CO NPs formation.

Figure 5. FT-IR spectral studies of synthesised CO NPs.

3.4. Diffused reflectance spectroscopy (DRS) analysis

The characteristic optical property of synthesised CONPs was investigated by DRS studies recorded at wavelength ranges of 800–200 nm (Figure 6(a)). The physical property (Eg-energy band-gap) of synthesised CONPs was found via Kubelka-Munk method (Equation 2(2) $$F\left(R\right)=\frac{{(1-R)}^2}{2R}=\frac{K}{S}$$(2) ) with the correlation between the diffuse reflectance of the CF NPs (R), the absorption coefficient (K) and the scattering coefficient (S) (Manjunatha 2020); (2) $$F\left(R\right)=\frac{{(1-R)}^2}{2R}=\frac{K}{S}$$(2)

Figure 6. Diffuse reflection spectra and wood and Tauc’s plot (inset) of synthesised CO NPs.

Tauc equation used for Eg value and linear absorption coefficient (α) of synthesised CO nanomaterial, as expressed by Equations (3)(3) $$⍺=\frac{{C_1(h\nu -Eg)}^{\frac{1}{2}}}{h\nu }$$(3) and (4)(4) $${\left[F\right(R\left)h\nu \right]}^2=C_2\left[h\nu -Eg\right]$$(4) ; (3) $$⍺=\frac{{C_1(h\nu -Eg)}^{\frac{1}{2}}}{h\nu }$$(3) (4) $${\left[F\right(R\left)h\nu \right]}^2=C_2\left[h\nu -Eg\right]$$(4)

The Eg value of the synthesised CONPs was measured to be 1.77 eV (Inset of Figure 6), which was derived by projecting the linearly fitted areas to [F(R)hν]² = 0 from the [F(R)hν]² vs. hν plot. Since visible light causes a greater photo-response, the resulting finding of rather narrow Eg values supports this hypothesis. The following formulae can be used to determine the band edge locations of synthesised CONPs: (5) $$E_{VB }=X-E_{0\mathrm{ }}+0.5\mathrm{ }Eg$$(5) (6) $$E_{CB }=E_{VB }-Eg$$(6)

Here, X-electronegativity of sample, E₀-energy with respect to SHE for about 4.5 eV, and E_CB and E_VB indicates valence-band and conduction-band edge potential, respectively. Edge potential E_VB and E_CB of synthesised CONPs were found to be −1.73 and −0.04 eV, respectively with the help of electronegativity values of prepared material found at 1.88 eV. These recorded data confirm its excellent photo-catalytic application for lower Eg value of green fuel assisted synthesised CONPs (Basavaraju et al. 2021; Dinamani et al. 2023).

3.5. Photocatalytic degradation studies on dyes

The waste water that was disposed into surrounding water system released from many sectors like industrial or domestic regions are currently causing serious issues all over the world. To treat the diverse dye-contaminated water, photo-catalytic activity is a useful method that has recently attracted greater attention. It was a field that covered a wide range of reactions, including surface modification, water decontamination, and toxin elimination, dehydrogenation with hydrogen transfer, and complete or light oxidation processes. Due to their extensive range of electronic states and band energies, semiconductors are the most widely used heterogeneous photocatalysts because they possess intrinsic physical and chemical properties that distinguish them from metals and prevent the electron hole recombination caused by photo-activation. The band-gap from the full valence band to empty conduction-band is also taken into account.

The photocatalytic dye-degradation activity of synthesised CO NPs was explored on AR-88 dye under effect of irradiation of UV-light. Photocatalytic analysis on dye decolouration was carried out for 40 ppm AR-88 dye in presence of 20 mg of CO photocatalyst, which is measured its absorbance of dye under UV-Visible spectroscopy (Figure 7(a)). Under UV-light irradiation, CO photocatalyst showed a maximum photodegradation performance of 97.6% for the AR-88 dye after 135 min (Figure 7(b)). Also, Figure 7(b) shows that the dark and photolysis photo-degradation performances of AR-88 dye were 9.3 and 13.8%, respectively. Furthermore, by plotting (C/C0) vs. time under UV-light irradiation, we discovered that the half-time of photodegradation activity of AR-88 dye in the occurrence of the produced CO photocatalyst was 29.8 min (Figure 7(c)). After five cycles were completed under constant settings, Figure 7(d) displays an analysis of the CO photocatalyst’s capacity to recycle its performance on the discolouration of AR-88 dye.

Figure 7. (a) Spectral absorbance of CONPs with the variation of irradiation time under visible-light irradiation of AR-88 dye; (b) percentage decomposition of AR-88 dye under visible-light irradiation; (c) half time and (d) stability performance of CO NPs.

3.5.1. Photocatalytic studies of AR-88 dye

Under UV irradiation, CO photocatalyst demonstrates a strong catalytic activity in the photodegradation of AR-88 dye. The photocatalysis can be elucidated based on the appearance of chromophore groups and azo linkages (–N = N–) in dyes, which exhibit a prominent peak at 502 nm wavelength due to the n → π* transition that is photocatalytically degraded in the presence of UV radiation. Thus, the CO photo-catalyst was absorbed an energy from light radiation and produces several holes and electrons before the deterioration began at room temperature (Equation 7(7) $${Co}_3{O}_4\mathrm{ }\mathit{NPs}+\left(UV \mathit{energy}\right)----\to {Co}_3{O}_4^{\star }\left(\mathit{Energy}\right)$$(7) ). these resulting charges are directly responsible to creation of several free active radicals, such as OH^•, and O₂^•− groups by gaining holes and electrons (Equations 8(8) $${Co}_3{O}_4^{\star \mathrm{ }}\left(\mathit{Energy}\right)--------\to {Co}_3{O}_4\mathrm{ }\left(h^{+}+e^{-}\right)$$(8) and 9(9) $${Co}_3{O}_4\mathrm{ }\left(e^{-}\right)+O_2----\to O^{2\mathrm{⦁}-}\left(\mathit{Superoxide} \mathit{radical}\right)$$(9) ). Hence, these radicals are identified as major contributors to the degradation process in the textile dyes (Equation 10(10) $$O^{2\mathrm{⦁}-}+H_{2}O--------------\to {OH}^{\mathrm{⦁}}+{OH}^{-}$$(10) ) (Figure 8) (Lakshmi Ranganatha et al. 2020; Raghavendra, Nagaswarupa, Shashi Shekhar, Mylarappa, Surendra, Prashantha, Ravikumar, et al. 2021; Surendra et al. 2018; Surendra and Veerabhadraswamy 2017) (7) $${Co}_3{O}_4\mathrm{ }\mathit{NPs}+\left(UV \mathit{energy}\right)----\to {Co}_3{O}_4^{\star }\left(\mathit{Energy}\right)$$(7) (8) $${Co}_3{O}_4^{\star \mathrm{ }}\left(\mathit{Energy}\right)--------\to {Co}_3{O}_4\mathrm{ }\left(h^{+}+e^{-}\right)$$(8) (9) $${Co}_3{O}_4\mathrm{ }\left(e^{-}\right)+O_2----\to O^{2\mathrm{⦁}-}\left(\mathit{Superoxide} \mathit{radical}\right)$$(9) (10) $$O^{2\mathrm{⦁}-}+H_{2}O--------------\to {OH}^{\mathrm{⦁}}+{OH}^{-}$$(10)

Figure 8. Mechanism of photocatalytic activity of AR-88 dye degradation.

3.5.2. Scavengers analysis

This scavenging investigation reveals that the reactive oxidative species are involved directly in dye degradation process by the impact of various scavengers, like isopropanol (IP, 5 mM), ascorbic acid (AA, 5 mM), and ammonium oxalate (AO, 5 mM). The conducting experiment was very similar to the photocatalytic process, but before the photo-catalyst (CO NPs) was added to the AR-88 dye solution, the specific quantity of scavengers was added. This experimental photo-degradation analysis was shows 77.6, 47.4, and 19.6% for ascorbic acid, ammonium oxalate, and isopropanol scavengers, respectively (Figure 9). This result confirms that isopropanol scavenger shows excellent photocatalytic activity by blocking the holes. Hence, photo-degradation performance of AR-88 dye was successfully achieved by holes as an effective tool under UV-light irradiation.

Figure 9. Scavenging analysis.

3.6. Electrochemical analysis

Observing the redox reaction of the completed cobalt oxide carbon paste electrode (COCPE) at scan rates ranging from 0.01 to 0.05 V/s in 1 M KOH with a 3-electrode system and CV and EIS methods yielded insight into the electrode’s electrochemical characteristics (Figure 10(a)). The good current measured in the potential range of −0.35–0.6 V yielded a CV voltammogram of COCPE. The reversibility of a redox reaction is measured by observing how anodic peak (Epa) and cathodic peak (peak Epc) potentials shift with time. The Randles-Sevecik equation (Raghavendra, Nagaswarupa, Shashi Shekhar, Mylarappa, Surendra, Prashantha, Basavaraju, et al. 2021; Shruthi et al. 2017) is used to determine the peak current (ip) and the potential difference (Ea,c), which both point to a lower value of 0.45 V, signifying more reversibility of COCPE.

Figure 10. (a) CV plot of COCPE at different scan rates in 1 M KOH solution; (b) EIS spectra; (c) relationship between the square root of the scan rate and the cathodic peak current (ip); (d) amperometry spectra of COCPE.

As can be shown in Figure 10(b), the frequency range for the EIS analysis of the COCPE was 1 Hz to 1 MHz, and the amplitude was held constant at 5 mV. Research using the EIS-Nyquist method shows that the semicircle arises at high frequencies, where charge transfer resistance is strong, and at low frequencies, when material capacitance is high (Rashmi, et al. 2020). High capacitance and high charge-transfer resistance (Rct) are shown by EIS-Nyquist analysis of COCPE, which reveals that its smaller semicircle arc liable towards the X-axis is 32Ω.

In the high-frequency portion of the Nyquist plot, the semicircle represents charge transport through the electrode-electrolyte interface, while the straight line represents electrode capacitance in the low-frequency zone. The diameter of the semicircle arc on the real axis can be determined from the amount of the Rct (Ravi Kumar et al. 2017). For a reversible process, the Randles-Sevcik-Sevcikon utilises the current height (Equation 11(11) $$\mathrm{ip}=2.69\mathrm{ }\times {10}^{5\mathrm{ }}\times n^{3/2}\mathrm{ }\times A \times D^{1/2}\times C_o\mathrm{ }\times v^{1/2}$$(11) ) (Raghavendra, Nagaswarupa, Shashi Shekhar, Mylarappa, Surendra, Prashantha, Basavaraju, et al. 2021). (11) $$\mathrm{ip}=2.69\mathrm{ }\times {10}^{5\mathrm{ }}\times n^{3/2}\mathrm{ }\times A \times D^{1/2}\times C_o\mathrm{ }\times v^{1/2}$$(11)

The notations n, A, D, v, and Co are used to represent reaction parameters. These figures represent the quantity of electrons moved throughout the reaction. Electrode size and scanning rate (For the COCPE (12) $$C_o=\frac{\rho }{\mathrm{ }M}/M$$(12) also affects the chemical’s initial concentration.

In Figure 10(b), we can see that the cathodic peak current (ip) for a COCPE is proportional to the square root of the scan rate (v^1/2). Hydrogen diffusion limits the COCPE’s electrode reactivity, as seen by the tighter linear connection between ip and v^1/2, as stated in (Ravi Kumar et al. 2017). Based on the slope of fitted line in Figure 10(c) and Equation (12), we get a value of 2.0165 × 10⁻⁵ cm²s⁻¹ for the COCPE’s hydrogen diffusion co-efficient. Figure 10(d) displays amperometric i–t curve found for COCPE during potential sweep of −0.4–0.6 V, it shows current linearity with respect to time which corresponds to the prepared COCPE is stable in 1 M KOH solution.

3.6.1. Sensor activity of COCPE

The chemical and bio-molecules sensor characteristics of modified COCPE were carried out with variety of concentrations of analyte at specific scan-rate of 3 mV/s in 1 M KOH. Figure 11(a) displays the CV plot of COCPE for paracetamol detection with various concentrations of 1–5 mM in 1 M KOH. The stronger potential variations in redox peak potentials and appearance of extra peaks at 0.127, 0.057, and −0.093 V confirm sensing action of paracetamol chemical (Uma et al. 2023). Similarly, the sensing activity of COCPE towards glucose bio-molecule was reported in 1 M KOH electrolyte as shown in Figure 11(b), it confirms the presence of peaks at different potentials at 0.183, −0.09, and −0.241 V, respectively. Even also the terminal peak in the + ve side move towards down (−ve current side), these distinctions confirm that our prepared COCPE senses both paracetamol and glucose in higher impact.

Figure 11. CV plot of COCPE (a) paracetamol (b) glucose bio-molecule sensors, amperometric i–t curve COCPE for the sensing of (a) paracetamol and (b) glucose bio-molecule using 1 M KOH electrolyte.

Amperometric i-t curves for paracetamol and glucose biomolecule sensing throughout a −0.4–0.6 V potential sweep are displayed in Figures 11(c,d), respectively. Figure 10(d) displays the first current response of COCPE at paracetamol and glucose concentrations of 0 mM. In addition, the current response grew and reached a constant current under 3s after repeated injections of 1 mM of paracetamol or glucose at a sampling interval of 50 s. Rapid amperometric reaction to the oxidation of paracetamol and glucose demonstrated by the sensor is clear from this sort of activity. The current manufactured sensor has been discovered to have a sensitivity of 0.0102 A for paracetamol and 0.0103 A for glucose (Avinash et al. 2019).

Figure 12 shows the calibration curve, and variation of peaks current as a function of concentration of Paracetamol and glucose using CO electrode with fitted data (inset), respectively. The limit of detection (LOD) (Kusuma et al. 2020) of paracetamol and glucose are as low as 1.00 × 10⁻³mol/L. The linear characteristic of the calibration curve confirms that the activity is a diffusion controlled in the measured concentration range.

Figure 12. Variation of peak current as a function of (a) paracetamol and (b) glucose concentrations with fitted data of CO electrode.

4. Conclusions

The summary of the reported research encloses the systematic analysis of prepared CONPs by Aloe-Vera latex mediated solution combustion approach. An Examination of the Structure by using PXRD methods, it was determined that the crystallite size of CONPs was 36 nm and that it exhibits a cubic, crystalline structure. Using the UV-Visible absorbance spectrum method and the Kubelka-Monk function, the optical tests revealed a band-gap of 1.77 eV. It was reported that AR-88 dye (40 ppm) degraded by 98.8 percent in 135 min when exposed to UV light in the presence of CO photocatalyst. Enhanced electrochemical behaviour and sensor performance on paracetamol chemical and glucose bio-molecule of COCPE was recorded by CV and EIS methods in 1 M KOH. These analyses revealed that CONPs is an effective and promising material for electrochemical sensor and photocatalytic studies.

Code availability statement

Not applicable.

Disclosure statement

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

Data availability statement

The data and materials that support the findings of this study are available with the corresponding author.

Additional information

Funding

Not applicable.