Photocatalytic hydrogen generation from raw water using zeolite/ polyaniline@Ni 2 O 3 nanocomposite as a novel photo-electrode Mohamed Adel Sayed a , Mostafa R. Abukhadra b, * , Mohamed Abdel Salam c , Sobhy M. Yakout d, e , Ahmed A. Abdeltawab f , Ibrahim M. Aziz g a Chemistry Department, Faculty of Science, Beni-Suef University, 62514, Beni-Suef City, Egypt b Geology Department, Faculty of Science, Beni-Suef University, Beni-Suef City, Egypt c Chemistry Department, Faculty of Science, King Abdulaziz University, P.O Box 80200, Jeddah, 21589, Saudi Arabia d Department of Biochemistry, College of Science, King Saud University, Riyadh,11451, Saudi Arabia e Department of Analytical Chemistry and Control, Hot Laboratories and Waste Management Center, Atomic Energy Authority, Cairo,13759, Egypt f Department of Chemistry, College of Science, King Saud University, Riyadh,11451, Saudi Arabia g Department of Botany and Microbiology, College of Science, King Saud University, Riyadh,11451, Saudi Arabia article info Article history: Received 16 October 2018 Received in revised form 6 August 2019 Accepted 12 August 2019 Available online 13 August 2019 Keywords: Polyaniline Zeolite Ni 2 O 3 Composite Photo-electrode Hydrogen abstract Novel heulandite/polyanailine@Ni 2 O 3 composite (Hu/PAN@NiO) was fabricated as an advanced product of enhanced photocatalytic properties and low band gap energy for efficient hydrogen generation. The composite was characterized and identified through different techniques including XRD, HRTEM, SEM, and FTIR in addition to the investigation of its textural and optical properties. The fabricated composite is of a significantly high surface area (531 m 2 /g) and low band gap that reaches about 1.46 eV which strongly qualifies the product electrode in photo-electrochemical hydrogen generation processes. The synthetic composite exhibits effective photocatalytic performance in the photoelectrochemical splitting of water under a visible light source. The detected photocurrent density reached 4.7204 mAcm 2 and the hydrogen production rate was estimated to be 4.1 mmol/h 1 cm 2 after about 50 min at an applied voltage of þ1V. The obtained results reflected the potentiality of such hybrid material as an effective catalyst in the photo-electrochemical splitting of water for hydrogen production. © 2019 Elsevier Ltd. All rights reserved. 1. Introduction Under the uncontrolled and rapid development of urbanization and industrialization, energy and clean environment became the biggest concerns in the world [1]. It was reported that the reserves of the common petroleum and fossil fuel resources may be exhausted within 10 decades [2]. This associated with excessive emission of harmful gases as SOx, NOx, CO 2 , and CO under the continuous consumption of such fuels which affected badly the human health and his ecosystem [3e6]. Recently, hydrogen was introduced as a clean fuel that can be generated from renewable resources and characterizes by its low cost, high consumption power and no associated pollutants [7]. Among the commonly used hydrogen generation techniques, the photocatalytic and photo-electrochemical water splitting methods were recommended for their environmental and economic value as they can be conducted utilizing artificial light source or the sunlight as the source of energy [8,9]. Thus, developing novel photocatalysts with low band gap energies and low fabrication costs is the main challenge for commercial hydrogen generation by photoelectric process [10]. Several types of materials were studied for this target including metal sulfides, metal oxides, metal oxy-sulfides, Sn- doped hematite, indium oxide, cobalt oxyhydroxide, cobalt- modified BiVO 4 , metal oxy-nitrides, and metal to non-metal ni- trides [11e 13]. Semiconductor metal oxides were investigated as photo- electrodes in the photoelectric hydrogen generation as they can be activated within a wide light region from UV zone to visible light zone. But the recorded rapid recombination of the charges carriers reduces their efficiency significantly [14e18]. Supporting of the metal oxides by the suitable substrates was suggested as a tech- nique to avoid the recombination problem in addition to the role of the substrate in enhancing the exposed surface area, and the number of interacting active sites by preventing the agglomeration * Corresponding author. E-mail address: abukhadra89@science.bsu.edu.eg (M.R. Abukhadra). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy https://doi.org/10.1016/j.energy.2019.115943 0360-5442/© 2019 Elsevier Ltd. All rights reserved. Energy 187 (2019) 115943