1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 z Materials Science inc. Nanomaterials & Polymers A Facile Green Reduction for Graphene-Silver Nanocomposite Using Betel Leaf Extract for the Photocatalytic Degradation of Water Pollutants Basavaiah Chandu, Sharmila Nurbasha, and Hari Babu Bollikolla* [a] Green leaves are utilized in the green synthesis of various nanomaterials as these are rich sources of various biomolecules useful to control the growth of nanoparticles and as reducing agents. In this report, the in situ synthesis of a nanocomposite of silver decorated on reduced graphene oxide sheets using betel leaf extract as stabilizing and reducing agent is presented. The formation of nanocomposite is confirmed by Ultraviolet- Visible, Fourier Transform Infrared and Raman spectroscopic techniques. The X-Ray Diffraction results revealed the Face Centered Cubic structure of silver nanoparticles (Ag NPs) with a particle size of 28 nm. The sheet structure of reduced graphene oxide and uniformly distributed Ag NPs on these sheets is confirmed by High Resolution Scanning Electron Microscope analysis. The obtained nanocomposite exhibited good photo- catalytic efficiency (95% in 2 h) against a model pollutant, methylene blue in sun light. Introduction Atomic thick single sheet of graphene is an emerging material with remarkable properties (more than 13341 Scopus indexed publications in 2016). The perusal of graphene and its composites with metal nanoparticles revealed that graphene- metal nanocomposites are investigated for putative applica- tions such as fabrication of field effect transistors (FET), [1] dye- sensitized solar cells, [2] electromechanical resonators, [3] electro- chemical sensors [4] and lithium ion batteries. [5] The extraordinary conducting nature of graphene which enhances the photo- catalytic activity of diverse nanomaterials makes it a desirable solid support to fabricate innovative graphene-based compo- site photocatalysts. The recent studies revealed that graphene is traditionally used as a support to stabilize and disperse metal, metal oxide and semiconductor nanomaterials such as Au, Ag, Pd, Pt, ZnO, TiO 2 , Co 3 O 4 , Fe 3 O 4 , CdS and ZnS for enhanced photocatalysis. [6–8] The large surface area of graphene associ- ated with its strong van der Waals attractive force for metal nanoparticles (NPs) reduces aggregation of metal NPs as well as graphene sheets and thereby improves the stability. [9] The exceptional electrical, thermal, catalytic and optical properties of silver coupled with its antibacterial activity has made the silver-based composites to be utilized for a broad spectrum of applications including conductive adhesives, solar cells, optical sensors and photocatalysis. [10–11] In situ methods of graphene-silver nanocomposites prepa- ration involves the simultaneous reduction of GO and Ag + ions using reducing agents such as NaBH 4 , [12] NH 2 NH 2 , [13] formaldehyde [10] etc. But these methods are not admirable owing to their highly poisonous and explosive [14] nature, they may also lead to the problems such as DNA damage, [15] abnormalities in blood and damage of the central nervous system. [16] Thus the presence of trace amounts of these substances could potentially forbid graphene composites to utilize in bio and environmental applications. Further, the poisonous nature of these reducing reagents need great attention in handling during the synthesis and processing of the hazardous waste. [17] Therefore, better green reducing agents needs to be developed in order to address the afore mentioned problems. Natural products such as plant extracts (fruit extracts, seed extract and leaf extracts) are more attractive due to their cost effective availability, flexibility in handling, high biocompatibil- ity, highly eco-friendly and are rich sources of many phyto- chemical reducing agents. [18] The use of plant extracts as reducing agents will effectively reduce the environmental pollution, production cost and produces biocompatible materi- als. Literature has witnessed the synthesis of graphene and its composites according to the green chemistry point of view using eco-friendly reagents such as L-ascorbic acid, L–Lysine, glucose, tea polyphenols, mortino berry extract, Fenugreek seeds extract, E. Helioscopia L. Leaf extract, E. Bungei Bioss, W. Coagulans leaf extract, barberry fruit extract, etc. [17–28] Betel tree from Piperaceae family is native to Malaysia whose scientific name is Piper Betle which is popularly known as Paan in India (Vedic name-saptasira). [29] It is extensively cultivated in India, Sri Lanka and in some parts of South Asia owing to its wide use as a mouth freshener. Betel leaf has got great respect in Indian culture, it is offered in many cultural and traditional occasions. These leaves are traditionally treated for many diseases. The essential oil extracted from leaves which comprises of 21 different compounds is a key ingredient in [a] B. Chandu, S. Nurbasha, Dr. H. B. Bollikolla Department of Chemistry Acharya Nagarjuna University Guntur, Andhra Pradesh, India E-mail: dr.b.haribabu@gmail.com Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201702437 Full Papers DOI: 10.1002/slct.201702437 11172 ChemistrySelect 2017, 2, 11172 – 11176  2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim