Tailoring morphological characteristics of zinc oxide using a one-step hydrothermal method for photoelectrochemical water splitting application A.R. Marlinda a,* , N. Yusoff b , A. Pandikumar c , N.M. Huang d , Omid Akbarzadeh a , Suresh Sagadevan a , Y.A. Wahab a , M.R. Johan a a Nanotechnology and Catalysis Research Center, University of Malaya, 50603, Kuala Lumpur, Malaysia b Low Dimensional Materials Research Centre, University of Malaya, 50603, Kuala Lumpur, Malaysia c Electrochemical Materials Science and Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi, 630003, India d New Energy Science and Engineering, University of Xiamen Malaysia, Jalan Sunsuria, Bandar Sunsuria, 43900, Sepang, Selangor Darul Ehsan, Malaysia article info Article history: Received 18 March 2019 Received in revised form 17 April 2019 Accepted 14 May 2019 Available online xxx Keywords: Metal oxide Electrocatalysis Photoelectrocatalysts Hydrothermal Energy conversion abstract In the present paper describe the zinc oxide (ZnO) with various morphologies have been synthesized using the one-step hydrothermal method, in which the growth of ZnO nanostructures are significantly tailored by adjusting the pH level between 9 and 12 using 0.1 M Sodium hydroxide (NaOH). Significant results reveal the morphological properties of ZnO nanostructures varied with different pH values with the formation of ZnO nano- structures have different morphological such as a baton, star, flower, and rod-like struc- tures. The present results show the rod-like structure of ZnO nanostructures exhibits the highest photocurrent density of 746.61 mAcm 2 (at 1.23 V vs RHE) under simulated solar AM 1.5G illumination in Potassium hydroxide (KOH) medium, also the other morphologies. The dependent of the photoelectrochemical (PEC) water splitting properties on the different morphological of ZnO nanostructures are studied. Achieving the morphological evolution mechanism has become one of the method to obtain the production of the hydrogen growth regime used for solar energy conversion and their applied storage potentials. The application of the ZnO nanostructures for PEC water splitting was proposed with the adoption of screen-printed carbon electrodes (SPCEs). These are to quantify the best degree of the highest photocurrent density with one-step tailoring with an ideal modeling system to enhance PEC water splitting performances. Thus, the screen-printed carbon electrodes (SPEs) has been used as an alternative method for fabrication and photoelectrodes testings. © 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction ZnO is a well-known and flexible semiconductor material that has a broadband gap (3.37 eV) and wide excitation binding energy (60 meV) [1]. Due to these properties create ZnO nanostructures as an important material for photonic appli- cation especially in UV spectral range, and also can increase the effectiveness of excitation-emission within room temperature. Moreover, since ZnO nanostructures is an environmentally friendly and chemically stable as suitable * Corresponding author. E-mail address: drmarlinda2205@gmail.com (A.R. Marlinda). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (xxxx) xxx https://doi.org/10.1016/j.ijhydene.2019.05.109 0360-3199/© 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article as: Marlinda AR et al., Tailoring morphological characteristics of zinc oxide using a one-step hydrothermal method for photoelectrochemical water splitting application, International Journal of Hydrogen Energy, https://doi.org/10.1016/ j.ijhydene.2019.05.109