Silver Nanoparticles: Silver nanoparticles were prepared by adding metal 1mM solution of AgNO3 to different plant leaves extracts resulting in deep brown color NPs solution. After characterization, the results of all NPs are discussed below.Particle Size Analyzer Results: The particle size of all plant extracts was above 100nm as shown in graph but after mixing with metal solution, different size and shaped particles were formed. Banyan, Sapodilla, Jujube, Lemon and P. Lime gave NPs with size 1.4nm, 10nm, 11nm, 22nm and 47nm respectively.
Ag NPs with Banyan, Sapodilla and Jujube provided very small sized NPs as compared to others. These are average sizes but still satisfactory for the confirmation of NPs sizes. Graph 1: Particle Size of different Plant Leaves Extracts Graph 2: Particle size of Ag NPs with different plant Leaves ExtractsScanning Electron Microscopic Results:UV-Visible Spectrophotometric Results: Comparative study of UV Visible spectra of plant leaves extracts and NPs showed clear difference. Ag NPs with Banyan, Jujube, Lemon, Sapodilla and P.
Lime leaves extracts showed absorption between 400nm to 550nm. The solution turned into dark brown color after adding the Ag solution to plant leaves extracts which depicted the formation of NPs and absorption of visible region. Graph 3: UV-Vis Spectra of different Plant Leaves Extracts Graph 4: Ag NPs with different Plant Leaves ExtractsFT-IR Spectrometric Results: Because NPs were in solution form, which was a mixture of Ag NPs and Phytochemicals from plant leaves extracts, the FT-IR results contain peaks for O-H stretching, C-H stretching, C?C stretching, N-H bending, C=O stretching, C-H Bending, C-N stretching, =C-H bending at 3332cm-1, 2929cm-1, 2109cm-1, 1850cm-1, 1595cm-1, 1350 cm-1, 1047cm-1 respectively. (1)The peaks for multiple functional groups are due to the presence of different type of phytochemicals in sample solution. Graph 5: Ag NPs with different Plant Leaves ExtractsPotentiostat Electrochemical Measurements: Cyclovoltametric measurements were done in 0.1 M KOH as electrolyte, fabricated FTOs as a working electrode, Ag/AgCl reference electrode and Platinum as counter electrode. The acquired data revealed that onset potential of all Ag NPs fabricated FTOs was shifted towards lower value.
These fabricated FTOs showed high electron density as compared to FTO without fabrication. Also the shifting of oxidation potential towards lower value enhanced the water splitting; especially water oxidation (evolution of O2) of FTO. The onset potentials of FTOs fabricated with Ag NPs with Jujube, Banyan and P. Lime slowed the minimum oxidation potentials 1.58V, 1.57V and 1.52V respectively.
The irregularity in spectra and sudden rise and fall in graph line shows the instability of NPs material on FTO substrate that’s why NPs material starts oxidizing and reducing the water irregularly. High electron density due to NPs fabrication showed more current on FTO surface hence made the splitting of water at lower oxidation potential easy. Graph 6: Ag NPs with Jujube Leaves Extract Graph 7: Ag NPs with Banyan Leaves Extract Graph 8: Ag NPs with Sapodilla Leaves Extract Graph 9: Ag NPs with Lemon Leaves Extract Graph 10: Ag NPs with P. Lime Leaves ExtractAntimicrobial Investigations:NPs with different Plant Leaves Extract Gram Positive(Bacillus subtilis) Zone of Inhibition Gram Negative(Pseudomonas aeruginosa)Zone of InhibitionAg NPs with Sapodilla Leaves Extract 7mm 8mmAg NPs with Banyan Leaves Extracts 7mm 10mmAg NPs with Lemon Leaves Extracts __ 12mmAg NPs with P. Lime Leaves Extracts __ 12mmAg NPs with Heena Leaves Extracts 7mm 11mm Antimicrobial results revealed that pure extracts of all plant leaves extracts showed no antibacterial activity but the Ag NPs with Sapodilla, Banyan and Heena leaves extracts showed maximum resistance against gram positive bacteria. Also Ag NPs with Sapodilla, Banyan, P.
Lime, Lemon and Heena showed resistance against gram negative bacteria which is clearly indicated from the figures below. Zone of inhibition of Ag NPs with different plant leaves extracts are mentioned in table below. Copper Nanoparticles: Cu NPs were prepared by same method as discussed above (by mixing Plant leaves extracts and CuSO4 solution) and the color of the solution changed to sea green. In some cases the color of solution changed to light brown and on standing the solution for one day, precipitation were formed which were dissolved again on shaking. The synthesized NPs results are discussed as below. Particle Size Analyzer Results: Different size of Cu particles was obtained on reduction with plant leaves extracts. Jujube, Sapodilla and P.
Lime leaves extracts gave nano sized particles 40nm, 77nm and 65nm respectively. Cu NPs with lemon and banyan plant leaves extracts gave large sized particles whose size was above 100nm Graph 11: Cu NPs with different Plant Leaves ExtractScanning Electron Microscopic Results:UV-Visible Spectrophotometric Results: Graph 12: Cu NPs with different Plant Leaves Extract