Tadesse thesis chemistry msc thesisPPT.pptx

Materials Required:
- Platinum(II) chloride (PtCl₂)
- Ammonia (NH₃)
- Distilled water
- Reaction vessel and fume hood
- General Experimental Approach:
1. Preparation of Platinum Complexes:
- Dissolve PtCl₂ in distilled water.
- Add aqueous ammonia gradually to form a yellow [Pt(NH₃)₂Cl₂] solution.
2. Controlled Conditions:
- Maintain specific pH and temperature to favor the formation of desired isomers (cis or trans).

1. June 30, 2023 www.bdu.edu.et BAHIR DAR UNIVERSITY COLLEGE SCIENCE DEPARTMENT CHEMISTRY MSC THESIS ELECTROCHEMICAL STUDY OF HYDROGEN PEROXIDE USING GREEN SYNTHESIS BISMUTH FERRITE NANOPARTICLE FROM MORINGA OLEIFERA L. LEAF EXTRACT WITH MODIFIED GRAPHITE PENCIL ELECTRODE By Tadesse A Advisor: Dr.Yonas B June 2023 Bahir dar, Ethiopia 1

2. June 30, 2023 www.bdu.edu.et 2 O utline

3. Hydrogen peroxide is a versatile and valuable compound that has numerous applications in various industries and factories. The effect of concentration of H 2 O 2 in industrial factories on human health cannot be ignored. In high concentrations, H 2 O 2 can be extremely hazardous to human health. In this way, the development of simple, low cost and fast analytical methods capable of monitoring H 2 O 2 , even at very low concentration, is fundamentally important. June 30, 2023 www.bdu.edu.et 3 INTRODUCTION

4. Various techniques to determination hydrogen peroxide , However, electroanalytical methods are low cost, ease of operation, low detection limits, quick detection, and sensitivity to different analyses. In electroanalytical method variety of working electrodes are used but, the graphite pencil electrode is known as a readily available, cost varies that can be modified. T he multiferroic oxides like BFO exhibit magnetic and electric properties. It can coexist and couple have various application like sensors. June 30, 2023 www.bdu.edu.et 4 Cont…

5. Nanomaterial can be prepared by chemical, physical and biological method. T he biological method have number of advantages over other as it is a cost effective and ecofriendly. June 30, 2023 www.bdu.edu.et 5 Cont…

6. June 30, 2023 www.bdu.edu.et 6 Statement problem

7. June 30, 2023 www.bdu.edu.et 7 Significant study

8. June 30, 2023 www.bdu.edu.et 8 Objective of the study

9. June 30, 2023 www.bdu.edu.et 9 Cont…

10. methodology June 30, 2023 www.bdu.edu.et 10 METHODOLOGY Chemical (Bi(NO 3 ) 3 ·5H 2 O Fe(NO 3 ) 3 ·9H 2 O Moringa oleifera L. leaf extract Nitric acid Distilled water PBS Equipment Magnetic stirrer with hot plate Glass beaker stir rod Filter paper Volumetric flask measuring cylinder Oven and frnance Analytical balance

11. June 30, 2023 www.bdu.edu.et 11 Preparation of Moringa oleifera L. leaf extract

12. Synthesis of BFO nanoparticles using Moringa oleifera L. leaf extract flow chart June 30, 2023 www.bdu.edu.et 12 Cont…

13. June 30, 2023 www.bdu.edu.et 13 Characterize the green synthesized of BFO NPs Spectroscopic technique X-Ray diffraction (XRD), SEM spectroscopy, UV-Visible spectroscopy Fourier transform infrared (FT-IR) spectroscopy Electrochemical experiment The bismuth ferrite modified PGE as WE The silver electrode As RE The platinum wire As CE

14. June 30, 2023 www.bdu.edu.et 14 Electrochemical modification of the PGE Bismuth ferrite was precipitated on the PGE by hot solution of BFO nanoparticle for 30 min at 100 C then t he electrode was rinse and dried. Preparation of the working electrode The surface of the pencil lead was polished. tightly covered with a tube A copper wire was soldered to the working electrode The pencil lead was held vertically and immerse in a solution

15. www.bdu.edu.et 15 RESULT AND DISCUSSION The study of structure Using XRD the BFO NPs crystal structure and average crystal size calcined at three different temperatures were analyzed. XRD peaks show two phase i.e. Bi 2 O 3 & BiFeO 3 . The annealing at all temperature led to the formation of impurity phases like Bi 2 O 3. All pure BiFeO 3 phase peaks observed in XRD spectra were attributed to all space group R-3m, hexagonal crystal planes. the peaks at 22.5º and 32º considered for the average crystal size calculation. June 30, 2023

16. www.bdu.edu.et 16 Cont… T he average crystal size can be determined using the Scherrer equation At lower annealing temperatures, such as 450°C, the average particle size was smaller, as the particles may less likely to aggregate and fuse with one another. At higher temperatures, such as 550°C and 650°C, the particles have more energy, may leading to greater aggregation and larger particles. June 30, 2023 BFO at Temperature 4450 °C 550 °C 650 °C average crystal size 14 nm 20 nm 26 nm

17. www.bdu.edu.et 17 Study of morphology SEM can be used to characterize the morphology of synthesized BFO nanoparticles that have been annealed at 450 °C (a), 550 °C (b), and 650 °C (c) as show figure. The SEM show change BFO NP in shape, surface and degree of crystallite due to temperature variation. June 30, 2023

18. June 30, 2023 www.bdu.edu.et 18 UV analysis BFO NPs calcined at different temperature with the corresponding bandgap energy. The exact position of the absorption peak was varying from sample to sample. The study optical properties

19. June 30, 2023 www.bdu.edu.et 19 The absorption spectra of BFO nanoparticles was strongly influenced by the temperature of the sample. As the temperature increases, the spectra shift towards longer wavelengths due to thermal expansion of the lattice, which alters the electronic structure of the material. An increase in temperature resulting in a more ordered crystal structure and fewer defects, which can further alter their optical properties. Cont.…

20. June 30, 2023 www.bdu.edu.et 20 The study of chemical composition Bond peak at wavenumber (cm -1 ) Plant (a) BFO 450 ° C (b) BFO 550 ° C (c) BFO 650 ° C (d) -OH 3280 3320 3315 3370 C-H 2920 2935 2935 2935 C=O 1723 1775 1775 1775 C=C 1640 1444 1444 1444 C-O stretching 1240 1147 1147 1147 C-O-C stretching 1050 1012 1016 986 Bi-O stretching - 866 866 866 Fe-O stretching   700 695 690 Fe–O stretching mode - 586 586 586 O–Fe–O - 462 462 - At 450 °C, the FTIR spectrum of BFO nanoparticles shows a broad absorption peak at around 582 & 462 cm -1 , which corresponds to the Fe-O stretching mode. At 550 °C and 650 °C, the FTIR spectrum of BFO nanoparticles shows a similar absorption peak, but with a narrower and more intense shape.

21. June 30, 2023 www.bdu.edu.et 21 The electrochemical behavior of Fe(CN) 6 3-/4- can be investigated using bare pencil graphite electrode(a) and PGE modified by BFO (b) with a reference Ag/ AgCl electrode at different scan rate. The modified electrode has a surface area of 0.377 cm², while the bare electrode has a surface area of 0.147cm² . The modified electrode has a larger surface area, which can provide more active sites for chemical reactions compared to the bare electrode . CV characterization

22. June 30, 2023 www.bdu.edu.et 22 The results showed that the BFO modified pencil graphite electrode have electrocatalytic activity towards the Fe 2+ / Fe 3+ redox couple . The current increased with increasing scan rates, indicating that the reaction was diffusion-controlled. The Fig show CV in 0.1 M KCl solution containing 10 mM Fe(CN) 6 3-/4- at different scan rates of the linear curve Ip Vs ν 1/2 (b) using bare (a) modified (b) electrode. Cont.…

23. T he Fig show CV in 0.1 M PBS ( pH 8 ) containing 5.0 mM H 2 O 2 at scan rate 100 mV/s . June 30, 2023 www.bdu.edu.et 23 The CV results showed fundamental differences between the BFO modified PGE and the bare PGE. The bare PGE displayed only a small current within the analyte, while the BFO modified PGE exhibited highest current signal. This indicates that the BFO modified PGE has excellent electrochemical properties. Electrochemical behavior of H 2 O 2

24. June 30, 2023 www.bdu.edu.et 24 However, at higher scan rates, the peaks became broader and merged together. T he peak potential shifted to negative values as the scan rate was increased. This shift in peak oxidation potential indicates the irreversibility of the oxidation process involving hydrogen peroxide. CV was performed at different scan rates. The shape of the CV was observed to change with the scan rate. At lower scan rates, the peaks corresponding to the oxidation of H 2 O 2 were more defined and separated. Effect of scan rate

25. June 30, 2023 www.bdu.edu.et 25 The correlation coefficient for the linear relationship between peak current and square root of scan rate being higher than the correlation coefficient between peak current and scan rate indicates that the electrochemical reaction was diffusion-limited. Cont…

26. June 30, 2023 www.bdu.edu.et 26 T he effect of pH on the electro chemical oxidation of H 2 O 2 was investigated . The CV shows the electrochemical behavior of H 2 O 2 at different pH values (4-9 ) as show fig. Effect of pH The curve clearly showed that a pH of 8.0 yielded the highest electrooxidation signal. As a result, pH 8.0 was selected as the optimum pH for further experiments.

27. June 30, 2023 www.bdu.edu.et 27 T he potential of the anodic peak shifts to a more positive value with decreasing pH value. By comparing the obtained slope of 0.051V with the Nernstian slope of 0.0591almost near. m / n, where m & n is n o proton & electron . The number of protons and electrons that involved in the oxidation process of H 2 O 2 are equal as show reaction: 2 H 2 O 2 → O 2 + 2 H 2 O + 2e - Cont.…

28. June 30, 2023 www.bdu.edu.et 28 The amperometric response of the BFO nanoparticle-modified pencil graphite electrode with successive additions of H 2 O 2 was investigated. When H 2 O 2 was added to the phosphate buffer, it undergoes oxidation at the modified PGE surface and produces electrons. The sensitivity ( 7.5 µA/ mM ) , detection limit ( 0.0732 µM) and quantification limit ( 0.732 µM) from the calibration curve were determine . Amperometric application

29. June 30, 2023 www.bdu.edu.et 29 The amperometric response of a biosensor was measured after injecting different concentrations of substances such as 1mM hydrogen peroxide (H 2 O 2 ), 0.15 mM ascorbic acid (AA), 5 mM sucrose (SU), and 0.5 mM uric acid (UA) at a voltage 0.8 V as show Figure. The current responses of AA, SU, and UA were significantly decrease by 1.87%, 6.80%, and 9.52%, respectively compared to H 2 O 2. Interferenc e

30. June 30, 2023 www.bdu.edu.et 30 The amperometric response of a 1 mm H 2 O 2 solution stability of BFO modified pencil graphite electrode as show figure. Stability

31. June 30, 2023 www.bdu.edu.et 31 The modified electrodes have high sensitivity, selectivity, and stability towards the detection of hydrogen peroxide . G reen synthesis bismuth ferrite nanoparticle from Moringa Oleifera L. leaf extract holds great promise for the development of highly efficient sensors and energy storage devices. CONCLUSION

32. I would like to express my deepest appreciation and respect to my advisor Dr. Yonas Beyene . I would like to thank you: Dr. Belete A Melaku (PhD student) Tehunie (PhD student) June 30, 2023 www.bdu.edu.et 32 Acknowledgment

33. June 30, 2023 www.bdu.edu.et 33 Thank You For Your Attentive Attention