Enhanced Optical and Antibacterial Activity of Hydrothermally Synthesized Cobalt-Doped Zinc Oxide Cylindrical Microcrystals

Awais Khalid; Pervaiz Ahmad; Abdulrahman I Alharthi; Saleh Muhammad; Mayeen Uddin Khandaker; Mohammad Rashed Iqbal Faruque; Abdulhameed Khan; Israf Ud Din; Mshari A Alotaibi; Khalid Alzimami; Abdulrahman A Alfuraih; David A Bradley

doi:10.3390/ma14123223

Enhanced Optical and Antibacterial Activity of Hydrothermally Synthesized Cobalt-Doped Zinc Oxide Cylindrical Microcrystals

Materials (Basel). 2021 Jun 11;14(12):3223. doi: 10.3390/ma14123223.

Affiliations

¹ Department of Physics, Hazara University Mansehra, Khyber Pakhtunkhwa 21300, Pakistan.
² Department of Physics, University of Azad Jammu and Kashmir, Muzaffarabad 13100, Pakistan.
³ Department of Chemistry, College of Science and Humanities, Prince Sattam Bin Abdulaziz University, P.O. Box 173, Al-Kharj 11942, Saudi Arabia.
⁴ Center for Applied Physics and Radiation Technologies, School of Engineering and Technology, Sunway University, Bandar Sunway 47500, Selangor, Malaysia.
⁵ Space Science Centre, Universiti Kebangsaan Malaysia (UKM), Bangi 43600, Selangor, Malaysia.
⁶ Department of Biotechnology, University of Azad Jammu and Kashmir, Muzaffarabad 13100, Pakistan.
⁷ Department of Radiological Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia.
⁸ Department of Physics, University of Surrey, Guilford GU2 7XH, UK.

Abstract

Cobalt (Co) doped zinc oxide (ZnO) microcrystals (MCs) are prepared by using the hydrothermal method from the precursor's mixture of zinc chloride (ZnCl₂), cobalt-II chloride hexahydrate (CoCl₂·6H₂O), and potassium hydroxide (KOH). The smooth round cylindrical morphologies of the synthesized microcrystals of Co-doped ZnO show an increase in absorption with the cobalt doping. The antibacterial activity of the as-obtained Co-doped ZnO-MCs was tested against the bacterial strains of gram-negative (Escherichia coli, Klebsiella pneumonia) and gram-positive bacteria (Staphylococcus aureus, Streptococcus pyogenes) via the agar well diffusion method. The zones of inhibition (ZOI) for Co-doped ZnO-MCs against E. coli and K. pneumoniae were found to be 17 and 19 mm, and 15 and 16 mm against S. Aureus and S. pyogenes, respectively. The prepared Co-doped ZnO-MCs were thus established as a probable antibacterial agent against gram-negative bacterial strains.

Keywords: absorption; antibacterial; cobalt-doping; microcrystals; synthesis.

Grants and funding

ISPP-20154(1)/International Scientific Partnership Program ISPP at King Saud University