(IJIRSE) International Journal of Innovative Research in Science & Engineering ISSN (Online) 2347-3207 Antibacterial Activities of CdO Microplates Synthesized by Hydrothermal Method K. Karthik a , S .Dhanuskodi a* , C. Gopinath b , S. Sivaramakrishnan b a School of Physics, Bharathidasan University, Tiruchirappalli – 620 024, Tamilnadu, India. b Department of Biotechnology and Genetic Engineering , Bharathidasan University, Tiruchirappalli -620 024, Tamilnadu, India. * E-mail: dhanus2k3@yahoo.com. Abstract— CdO microplates were synthesized (hydrothermal) with cadmium chloride and ammonium hydroxide as starting materials and characterized by XRD, FE-SEM with EDS and FTIR. It exhibits face centred cubic structure with an average crystallite size of 27 nm and the lattice strain (W – H Plot) is 0.0012. The surface morphological image displays microplate like structure with agglomeration. The vibrational stretching mode of Cd-O is 455 cm -1 . From the UV- Visible spectra, the optical energy bandgap is estimated as 2.56 eV. The significant antimicrobial activities were studied against gram negative (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris) and gram positive (Staphylococcus aureus, Enterococcus faecalis, Enterococci spp) bacteria. The zone of inhibition is found to be more for gram negative than for gram positive bacteria. Keywords- Antibacterial activity, Microplates, Hydrothermal, Structural and FT-IR. I. INTRODUCTION In recent research among the conducting oxides, there exists a promising candidate cadmium oxide (CdO), with specific features of low bandgap (2.2 – 2.7 eV), high conductivity (10 3 ohm -1 cm -1 ), high carrier mobility (142 cm 2 /Vs) and large linear refractive index (n o =2.49). CdO has shown applications in the fields of solar cells, photo transistors, transparent electrodes, catalysis and gas sensors [1]. It is an important II – VI semiconductor having NaCl crystal structure with alternating Cd and O atoms located at lattice points [2]. II. EXPERIMENTAL A. Material synthesis CdO microplates were synthesized by hydrothermal method with CdCl 2 and NH 4 OH as starting materials. Cadmium chloride was dissolved in 100 ml of double distilled water and ammonia solution was added dropwise into the above solution and was maintained at pH = 10. Then the solution was transferred to a stainless steel autoclave bottle kept at 150 C for 10 h in the hot air oven. The resulting solid product was washed with ethanol and double distilled water repeatedly and dried in air resulting with a solid powder and was sintered at 873 K for 6 h. Finally, it was grounded to get brown CdO powder. B. Instrumentation X-ray powder diffraction (XRD) studies were carried out to affirm the crystal structure using XPERT – PRO X-ray Diffractometer with Cu K radiation (1.5406Å) in the range of 10-70 o in steps of 0.0025 at a scan speed of 2 o /min. The morphology of the synthesized powder was examined by FE-SEM (JEOL – JSM – 6301 FE-SEM) and the chemical composition was investigated by EDAX (Bruker). The molecular structure was confirmed by JASCO 460 PLUS FTIR spectrometer (400-4000 cm -1 ). The linear optical absorption characteristics were recorded using Shimadzu UV-1800 spectrophotometer (200-800 nm). III. RESULT AND DISCUSSION A. Structural and morphological characteristics Fig. 1 shows the X-ray diffraction pattern of CdO microplates and the cell parameters are in good agreement with the JCPDS (75-0592) with a=0.469 nm for cubic phase. The broadened peaks reveal the synthesized microplates are of higher order of crystallinity and purity [3]. The crystallite size (D) is calculated using Scherrer’s formula