319 Acta Chim. Slov. 2018, 65, 319–327 Singh et al.: Solvothermal Synthesis of ZnO-Nitrogen Doped ... DOI: 10.17344/acsi.2017.3988 Scientifc paper Solvothermal Synthesis of ZnO-Nitrogen Doped Graphene Composite and its Application as Catalyst for Photodegradation of Organic Dye Methylene Blue Rajinder Singh, Manesh Kumar, Heena Khajuria, Jigmet Ladol, and Haq Nawaz Sheikh * Department of Chemistry, University of Jammu, Jammu Tawi, 180 006 India. * Corresponding author: E-mail: hnsheikh@redifmail.com Received: 10-11-2017 Abstract A facile one step solvothermal method is designed for the synthesis of visible light-sensitive ZnO-nitrogen doped graphene (ZNG) nano photocatalysts using ethylene glycol as a solvent as well as an agent to prevent aggregation of graphene layers. Te deposition of ZnO nanoparticles onto the NG layers was confrmed by high resolution transmission electron microscope (HR-TEM), scanning electron microscope (SEM), powder X-ray difraction (XRD), and Fourier transform infrared spectroscopy (FTIR). UV–Vis spectroscopy (UV-Vis) was used to study the enhanced photocatalytic activity, which shows the red-shif of the band-edge as compared to ZnO nano particles. Te enhancement in photocat- alytic activity is possibly due to the synergistic efect of improved adsorptivity of dyes, enhanced visible light absorption and efective charge separation. Keywords: ZnO; photocatalysis; methylene blue; nitrogen doped graphene 1. Introduction Te visible light degradation of organic pollutants have attracted the attention of the scientifc community worldwide due to the various reasons such as better ef- ciency, easy to operate and non toxic byproducts. 1–6 Te process of photocatalysis takes place by the absorption of light by the photocatalysts such as ZnO and TiO 2 and thereby promoting the electrons from valence band to the conduction band and forming the electron and hole pairs in the structure. 7–9 Te produced electron-hole pairs can move and start the various redox reactions involving water and oxygen and thus cause the degradation of organic molecules. However, the recombination of electrons and holes can lower the performance of photocatalyst ZnO. 10 In order to make the catalyst more efective, the recombi- nation of electron and hole must be hindered. Various ex- periments have been conducted to prevent the recombina- tion of electron and hole by combining the photocatalyst with the other materials such as non reactive metals 11,14 and semiconductors. 15,16 In addition, it has been found that deposition of semiconductor photocatalysts on a co-adsorbent surface such as mesoporous materials, zeo- lites, alumina, silica or carbon based materials may en- hance the photocatalytic activity of photocatalysts. 17–21 Among the various materials, carbon based materials are of great importance due to their excellent electronic prop- erties, adsorption capacity and unique structure. Te car- bon based materials include activated carbon, graphene and carbon nanotubes. 21–27 Graphene is a two-dimension- al monolayer network of conjugated carbon atoms having sp 2 -hybridization between the atoms. 28–32 Graphene has many advantages as compared to the carbon nanotubes (CNTs) such as high surface area and excellent adsorption on the surface of adsorbent. Graphene possesses the excel- lent electrical, thermal and mechanical properties by vir- tue of which it is used in the diverse areas and also as elec- trode materials for electrochemical capacitor. 31–34 However, despite all these facts graphene has to undergo some structural transformation to be used for many other applications. 35 Te doping of graphene with the heteroat- om (i.e, N-atom) can enhance the electron mobility and causes the larger capacitance. All these properties are at- tributed to the atomic size and strong valence bonds of nitrogen atoms. 36 In the recent years, nitrogen doped graphene (NG) has received much importance 37,38 Tus, it is favored to synthesize the N-doped graphene based nano