Structural, spectroscopic and biological investigation of copper oxides nanoparticles with various capping agents A. Nowak a, * , J. Szade a , E. Talik a , A. Ratuszna a , M. Ostafin b , J. Peszke a a A. Chelkowski Institute of Physics, University of Silesia, Katowice, Poland b Agricultural University of Cracow, Department of Microbiology, Krakow, Poland highlights  We obtained copper oxide nanoparticles in a powder form.  Several capping agents were tested.  Structural and chemical tests showed that the main component were Cu 2 O and CuO.  The size of nanoparticles was in the range 7e21 nm.  Nanoparticles with glycerin and ammonia capping agent showed good antibacterial properties. article info Article history: Received 26 June 2013 Received in revised form 9 January 2014 Accepted 28 February 2014 Keywords: Nanostructures Oxides Surfaces Electron microscopy (SEM) X-ray photo-emission spectroscopy (XPS) Crystallography abstract Powder composed of copper oxides nanoparticles with various capping agents has been synthesized and characterized with the use of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Polyvinyl alcohol (PVA), glycol propylene, glycerin and glycerin plus ammonia were used as capping agents. The scanning electron microscopy (SEM) studies showed that nanoparticles form agglomerates with the size from 80 to 120 nm while particles size determined from the XRD experiment was in the range from 7 to 21 nm. XPS and XRD experiments revealed that depending on capping and reducing agents used in the synthesis nanoparticles are composed of Cu 2 O, CuO or a mixture of them. The biological activity test performed for a selected sample where the capping agent was glycerin plus ammonia has shown promising killing/inhibiting behavior, very effective espe- cially for Gram negatives bacteria. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction Funguses and some bacteria have influence on life of many patients who have compromised immune system, such as people suffering from acquired immune deficiency syndrome and those receiving chemotherapy. The candidate to solve the problem can be metal nanoparticles. Their physical and chemical properties are intensively investigated. The bactericidal effect of metal nano- particles has been attributed to their small size, and high surface to volume ratio, which allow them to interact closely with microbial membrane and is not merely due to the release of metal ions in solutions. The antibacterial properties of the metal nanoparticles find application in various fields such as medical instruments and devices, water treatment and food processing. One of most prom- ising bacteriological killers are Ag and Au nanoparticles [1]. How- ever, their production still is expensive. Significantly cheaper but still good candidate are Cu nanoparticles. The antibacterial effects, the antifungal and bacteriostatic properties of copper nanoparticles was reported by Yoon et al. [2] and Cioffi et al. [3]. Researchers also show that they have attractive catalytic [4], optical [5] and electrical conducting [6] properties and effectively absorb aqueous arsenic species [7]. They can be also precursor in conductive ink [6,8] and have potential application in cooling systems [9]. Copper nano- particles have been obtained by several methods such as thermal reduction [10], vacuum vapor deposition [11], microwave irradia- tion methods [12], laser ablation [13] and chemical reduction [14]. Those methods use oxygen-free atmosphere to synthesize copper nanoparticles because they easily oxidize. In this paper we report a process of chemical synthesis taking place of copper oxides nano- particles and show their characterization by X-ray diffraction * Corresponding author. E-mail address: ana.maria.nowak@gmail.com (A. Nowak). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys http://dx.doi.org/10.1016/j.matchemphys.2014.02.049 0254-0584/Ó 2014 Elsevier B.V. All rights reserved. Materials Chemistry and Physics 145 (2014) 465e470