Tailored Synthesis of CN-PPy Composite for Enhanced Electrochemical Functionality

This study details the synthesis of pure carbon nitride (CN) and composite polypyrrole through an in-situ polymerization method. The prepared samples were comprehensively characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), and X-ray Diffraction (XRD). These analyses confirmed the chemical bonding, structural, and morphological characteristics of the products. Electrochemical measurements, conducted through cyclic voltammetry (CV) and Linear Sweep Voltammetry (LSV), revealed significant current rates in both anodic and cathodic peaks, indicating superior electrochemical properties. This work not only details the synthesis process but also provides a thorough understanding of the structural, morphological, and electrochemical aspects, exhibiting the materials’ potential for various applications in electrochemical devices.


Introduction
Significant progress has been made in science and nanotechnology worldwide in a number of fields in recent years.Among these are supercapacitors, solid state batteries, fuel cells, electrochemical sensors, bio-sensors, electrochemical corrosion, hydrogen evolution, bio-imaging, photovoltaic, biological electrochemistry, and electro-catalysis.Since the 20th century, most of the world's grid electricity has been produced using these technologies.[1] Supercapacitors, a type of energy storage device, fill a vital role in the energy storage industry by filling the void left by batteries and conventional capacitors.Their low cost, long cycle life, fast recharge capacity, high PD, and environmental friendliness have all drawn a lot of attention [2][3].and electrochemical sensors are implanted or external devices that are frequently used as diagnostic tools to identify human and animal diseases, as well as to monitor environmental pollution, test the presence of drugs in food and drink, as a result, growing concerns about environmental damage, global warming, and the energy crisis have spurred the development of sustainable alternative energy sources like wind and solar energy.To bridge these areas, the initial focus is on certain conducting polymers, such as derivatives of polypyrrole (PPY), polyaniline (PANI), polythiophene (PTH), and poly 3,4 ethylene dioxy thiophene (PEDOT), which are widely used in various industrial applications and also used in our daily lives due to their promising advantages, such as high machinability, lightweight, and low cost compared to metal and ceramic materials.These materials are our primary focus for the development of supercapacitor applications.Specifically, by adjusting the moieties and structures of side chains and backbones, polymer materials' properties can be precisely controlled to meet a range of application needs [4].Conducting polymers, like polypyrrole, polyaniline, and poly (3,4-ethylenedioxythiophene), have demonstrated great potential as active materials and electrodes for a variety of energy and electronic devices.And among various carbon materials, such as graphite and carbon nanotubes, the 2D material based on graphitic carbon nitride (CN) has generated the most discussion recently because of its remarkable performance as well as its unique architecture and properties [5][6].Because of its high sensitivity to analysts, quick response to external stimulations, excellent fluorescence quenching abilities, light and electricity conversion properties, biocompatibility, and high stability, the CN nano-sheet is a promising candidate as a modified electrode for sensors to detect various substances.New types of sensors to detect various materials have also been revealed by the CN loaded with metal oxides [7].This is because of their high levels of sensitivity, affordability, easy testing procedures, mobility, and fast reaction times.The precursors that are most commonly used to create CN are melamine, dicyandiamide, cyanamide, urea, thiourea, and ammonium thiocyanate [8].The synthesis and physical properties of CN were first covered.After that, we talked about how CN can be combined with various 2D metal oxides, metal sulfides, and conducting polymers to increase its efficiency and make the composites useful for a range of electrochemical applications.In this study, carbon nitride (CN) were synthesized via urea-assisted carbonization, while a polypyrrole composite was prepared through in-situ polymerization.Characterization using FTIR, XRD, and SEM confirmed the successful fabrication.Electrochemical properties were investigated through cyclic voltammetry (CV) and linear sweep voltammetry (LSV), providing insights into their performance.The combination of urea as a precursor and in-situ polymerization enhances the material's structural and morphological properties.This dual synthesis approach, along with detailed characterization and electrochemical analysis, offers a comprehensive understanding of the materials for potential applications in diverse electrochemical devices.

Synthesis of CN
CN is prepared via simple pyrolysis method, ten gram of Urea was placed into alumina crucible with cover and heated at 550°C for 2 hours in a semi closed system, by ramping time of 2°C/min.when the sample was cooled to room temperature sample was removed from muffle furnace the resultant yellowish powder is the desired CN, which is collected and ground into powder form for further use.

Synthesis of CN/PPy
The micelles self-degraded template method was used to prepare the CN/PPy composite.Typically, 50 milliliters of distilled water were used to dissolve 0.15 grams of CN powder.The CN solution was then vigorously stirred continuously while 0.48 grams of FeCl3 and 0.098 grams of methyl orange were added.Following a half hour, 0.15 milliliters of pyrrole monomer were gradually added to the aforementioned solution via injection while being constantly stirred.To finish the polymerization reaction, which was indicated by a color change brown to black, the mixture was stirred constantly for 24 hours.The resulting CN/PPy residue was filtered through Whatman paper after 24 hours, repeatedly cleaned with distilled water, and then baked for an entire night at 60 °C.

Characterization
Chemical compositions were studied using the Bruker Alpha ATR FT-IR spectrometer, structural analysis was carried out using the Rigaku X-ray diffractometer (XRD), surface morphology was examined using Sigma Zeiss Field Emission Scanning Electron Microscopy (FESEM), and electrochemical performance was carried out using a PC-based CHI 660E electrochemical workstation.[9].The vibration stretching bands of C-N and C-N heterocycles are responsible for a number of peaks seen in the CN spectra, including peaks at 1201 cm -1 , 1404 cm -1 , and 1653 cm -1 [10,11].The presence of PPy is confirmed by the characteristic peaks seen in the spectra of the CN/PPy composite at 692 cm -1 , 936 cm - 1 , and 1089 cm -1 .In addition, a peak at 1201 cm -1 is seen, which suggests that the CN/PPy composite is in a deformed state as opposed to pure CN.   100), [12] and represents the interlayer spacing in the in-plane direction of the repeating triazine units [13].The dominant peak is a broad peak at approximately 27.8 o .Similar XRD patterns can be seen in the CN/PPy composite, where a distinct peak can be seen around 27.8•.The major diffraction peak at 27.8• corresponds to the (002) Bragg's reflection, indicating the interlayer spacing, and its presence validates the interlamellar stacking of the aromatic region in the composite [14].Furthermore, it is clear from comparing the XRD patterns that

FESEM Analysis
The FESEM images of pure CN that were used to analyze surface morphology are shown in Figure 2 (a) The prepared samples show plate-like structures instead of regular morphology [15].The stacking morphology of CN is caused by van der Waals forces, which leads to a low specific surface area [16,17].The agglomeration of CN particles on the PPy surface, which increases the composite material's specific capacitance, is depicted in Figure 2 (b) The PPy may increase specific capacitance because they have a larger surface area and use less mass.Another explanation for the decreased PPy could be that the CN particle clusters compress the nanotube by taking up space.Moreover, PPy may be compressed by the CN particles [18].The observed morphological changes in the material may provide an opportunity to leverage its physical attributes, such as its large specific surface area, high conductivity, and good biocompatibility, of the CN/PPy composite.These characteristics aid in enhancing cyclic stability, raising the amount of energy stored, and speeding up the movement of hydrated ions [19].

Electrochemical performances 4.3.1. Cyclic voltammetry and Linear sweep voltammetry
The CHI 660E electrochemical workstation was used to perform the electrochemical performance.Two electrodes were used for the electrochemical measurements, and as Figure 3 illustrates, cyclic voltammetry can be used to determine the electrode's electrochemical performance in terms of reversible cathodic reduction and anodic oxidation in the voltage range of -0.8 to 0.8 V. (a) The reduction peak, which is connected to reduction in the cathodic zone and oxidation in the anode region, is clearly visible.The CN cyclic voltammetry displays a nearly rectangular-shaped area, but a smaller curve area is not beneficial for stable electrochemical performance.Greater specific capacitance and stable electrochemical behavior are caused by the larger curve integrated area, which is evident in the composite of CN/PPy Figure 3.(b) along with oxidation-reduction peaks.[20] b a The different scan rates applied to the CN, as shown in Figure 3, are analyzed by the LSV.(c) When comparing CN/PPy to CN, the I-V characteristic curve shows a linear increase in stability, which improves the superior I-V characteristics in the applied voltage range of -1 to 1 V.The LSV graph shows that the oxidation current increases in tandem with changing the sweep rate from 20 mV s-1 to 50 mV s-1.This suggests that the stability of the material is enhanced through electron diffusion, ions, and the charge transfer process, contributing to improved electrochemical performance.

Conclusion
In summary, this study successfully detailed the synthesis of pure carbon nitride (CN) and a composite with polypyrrole nanotubes using an in-situ polymerization method.Characterization through Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), and X-ray Diffraction (XRD) affirmed the chemical bonding, structural, and morphological features of the prepared samples.The electrochemical measurements, conducted via cyclic voltammetry (CV) and Linear Sweep Voltammetry (LSV), demonstrated high current rates in both anodic and cathodic peaks, indicating superior electrochemical properties.This work contributes valuable insights into the synthesis, characterization, and electrochemical behavior of the fabricated materials, suggesting their potential for applications in diverse electrochemical devices.

Figure 1 (
Figure 1 (a) displays the FT-IR spectra of the CN/PPy composite and pure CN.(a) The breathing mode of the tri-s-triazine unit is represented by the peak in the CN spectra at 801 cm -1[9].The vibration stretching bands of C-N and C-N heterocycles are responsible for a number of peaks seen in the CN spectra, including peaks at 1201 cm -1 , 1404 cm -1 , and 1653 cm -1[10,11].The presence of PPy is confirmed by the characteristic peaks seen in the spectra of the CN/PPy composite at 692 cm -1 , 936 cm - 1 , and 1089 cm -1 .In addition, a peak at 1201 cm -1 is seen, which suggests that the CN/PPy composite is in a deformed state as opposed to pure CN.

Figure 1 (
Figure 1 (b) shows the diffraction patterns of CN and CN/PPy composite XRD patterns of pure CN the CN sample exhibits a faint peak at 13.02•, which is indexed as (100),[12] and represents the interlayer spacing in the in-plane direction of the repeating triazine units[13].The dominant peak is a broad peak at approximately 27.8 o .Similar XRD patterns can be seen in the CN/PPy composite, where a distinct peak can be seen around 27.8•.The major diffraction peak at 27.8• corresponds to the (002) Bragg's reflection, indicating the interlayer spacing, and its presence validates the interlamellar stacking of the aromatic region in the composite[14].Furthermore, it is clear from comparing the XRD patterns that PPy to the CN/PPy composite causes the broad peak to become a slightly sharp peak, indicating an improvement in electrochemical functionality.