Research Article Green Synthesis and Characterizations of Zinc Oxide (ZnO) Nanoparticles Using Aqueous Leaf Extracts of Coffee (Coffea arabica) and Its Application in Environmental Toxicity Reduction Saka Abel, 1 Jule Leta Tesfaye, 1,2 R. Shanmugam, 3 L. Priyanka Dwarampudi, 4 Gudeta Lamessa, 1 N. Nagaprasad , 5 Mekonen Benti, 6 and Ramaswamy Krishnaraj 2,7 1 Department of Physics, College of Natural and Computational Science, Dambi Dollo University, Ethiopia 2 Centre for Excellence-Indigenous Knowledge, Innovative Technology Transfer and Entrepreneurship, Dambi Dollo University, Ethiopia 3 TIFAC CORE HD, Department of Pharmacognosy, JSS Academy of Higher Education and Research, JSS College of Pharmacy Ooty, Tamil Nadu, India 4 Department of Pharmacognosy, JSS Academy of Higher Education and Research, JSS College of Pharmacy Ooty, Tamil Nadu, India 5 Department of Mechanical Engineering, ULTRA College of Engineering and Technology, Madurai, 625104 Tamil Nadu, India 6 Department of Civics and Ethical Studies, College of Social Science and Humanities, Dambi Dollo University, Ethiopia 7 Department of Mechanical Engineering, College of Engineering and Technology, Dambi Dollo University, Ethiopia Correspondence should be addressed to Ramaswamy Krishnaraj; prof.dr.krishnaraj@dadu.edu.et Received 3 July 2021; Accepted 22 July 2021; Published 18 August 2021 Academic Editor: Shanmugam Rajeshkumar Copyright © 2021 Saka Abel et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A green deposition method of zinc oxide nanoparticles using coffee leaf extraction was successfully prepared. The use of these preparation techniques is accepted by many researchers because it is nonexpensive and simple and has no environmental impact during the operation. The determination and reduction of Zn ions to ZnO NPs were characterized by using a UV-visible spectroscope. The UV-visible spectroscopy result reveals that the large band gap energy is observed in the visible region at the wavelength of 300 nm. X-ray diffraction and SEM analysis confirm that the deposited nanoparticle is highly crystalline with (111), (222), and (100) planes and cubic shape structure. The coffee leaf extraction serves as a reducing agent for stability of the particle length, where its medicinal value outcome showed an important antibacteria of the pathogenic type which appeared on the wound. The present research deals with the green synthesis of ZnO NPs as well as its application in toxicity reduction. 1. Introduction Nanotechnology is the greatest innovative research part in today’s condensed material science which basically includes nanoparticles [1, 2]. Nanoparticles are types of materials with a 3D structure, changing in magnitude from 1 to 100 nano- meters. This material contains lots or 100s of atoms (molecules) that comprise different forms such as crystal structure, spherical, tubes, and amorphous [3]. Nanoparticles of metals like zinc have exceptional optical properties and electrical and magnetic material goods that make them broadly used in study and manufacturing events. Amongst the numerous behaviors of metal nanoparticles, the optical studies are more protuberant. The properties of metallic nanoparticles are because of occurrences called surface- plasmonic resonance. The applications of metal nanoparti- cles includes the following: their contribution in the area of electricity as well as thermal conductors, sensors, optical and electrochemical detectors, antibacterial materials, super paramagnetic materials [4, 5]. Mineral nanoparticles have numerous likely applications for medicinal imaging and illness cure, and they are used extensively for their diverse Hindawi Journal of Nanomaterials Volume 2021, Article ID 3413350, 6 pages https://doi.org/10.1155/2021/3413350