Electrodeposition of Ni-W and Ni-W-P films using a pulse current technique and their application for hydrogen evolution in an acidic solution Zeinab Abdel Hamid Corrosion Control and Surface Protection, Central Metallurgical Research and Development Institute, Helwan, Egypt, and H.B. Hassan and Mohamed Sultan Cairo University, Giza, Egypt Abstract Purpose – The improvement of the hydrogen evolution reaction (HER) performance requires more efficient and inexpensive electrocatalysts. The purpose of this study is to prepare Ni-W and Ni-W-P thin films using the electrodeposition technique using a pulse current and investigate their behaviors toward HER in an acidic solution. Design/methodology/approach – The aim is to prepare Ni-W and Ni-W-P films by the electrodeposition technique using a pulse current and estimate their performance for the HER. The surface morphologies and chemical compositions of the deposited films were assessed using scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. Linear sweep voltammetry, chronoamperometry, Tafel plots and electrochemical impedance spectroscopy were used to evaluate the prepared electrodes toward the hydrogen evolution process. Findings – The main conclusion is that the surface morphology of Ni–W deposited film is a crystalline structure, while that of Ni-W-P deposit is an amorphous structure. HER activity on Ni-W electrodes increases with decreasing the Wt.% of W to 7.83 Wt.% in the prepared electrodes. In addition, the presence of P enhances HER activity, which increases with increasing the Wt.% of P in the prepared Ni-W-P electrodes. Both Ni-W (7.83 Wt.% W) and Ni-W-P (20.34 Wt.% P), which have been prepared at 8 A dm 2 display the best performance toward HER compared to the other prepared electrodes. They exhibit high catalytic activities toward HER, which is evidenced by high hydrogen evolution current density values of 9.52 and 33.98 mA cm 2 , low onset potentials of 0.73 and 0.63 V, low Tafel slopes of 125 mV/dec, high exchange current densities of 0.058 and 0.20 mA cm 2 , low charge transfer resistances (Rct) of 226.28 and 75.8 ohm·cm 2 for Ni-W (7.83 Wt.% W) and Ni-W-P (20.34 Wt.% P), respectively; moreover, they exhibited considerable stabilities too. Originality/value – The results presented in this work are an insight into understanding the performance of the prepared Cu electrodes coated by Ni-W and Ni-W-P films toward HER. In this work, a consistent assessment of the results achieved on laboratory scale has been conducted. Keywords Coatings and linings, Electrochemistry, Surface preparation, Corrosion science, Development, Chemical process, Ni-W, Ni-W-P, Hydrogen evolution reaction, Ni alloys, EIS, Pulse electrodeposition Paper type Research paper 1. Introduction Currently, researchers are focusing on identifying clean and renewable energy resources alternative to fossil fuels (Potocnik, 2007). Hydrogen is an example of a clean fuel that provides an efficient source of energy and offers zero pollution. Therefore, it can be used as an alternative fuel for many applications (Uyar and Besikci, 2017; Wang et al., 2017; Schalenbach et al., 2016; Hosseini and Wahid, 2016, and Yang et al., 2015). The electrocatalytic hydrogen evolution reaction (HER) is among the various hydrogen preparation approaches that has attracted considerable interest because of its ease and generality (Liu et al., 2018; Shi et al., 2017; Liu et al., 2017, and Wang et al., 2017). The efficient catalysts for this reaction should be able to minimize the catalytic activation energy during a reaction (Zhang et al., 2016 and Moon et al., 2015). In addition, they should have long-term stability toward HER (Shi and Zhang, 2016). Among the catalysts used for HER are Pt and Pt-based alloys, which are considered as the best catalysts with highest efficiency but the high cost of Pt is a challenge (Zeradjanin et al., 2016; Sheng et al., 2010; Grigoriev et al., 2008). Therefore, identifying Pt-alternative catalysts is required to ensure that the hydrogen production process becomes more economic (Schalenbach et al., 2018; Emin et al., 2018; Mishra et al., 2018). Metallic alloy catalysts impart a wide-range of flexibility both in terms of activity and durability (Koboski et al., 2013 and Mavrikakis et al., 1998). Alloying of Ni with The current issue and full text archive of this journal is available on Emerald Insight at: https://www.emerald.com/insight/0003-5599.htm Anti-Corrosion Methods and Materials 67/1 (2020) 38–47 © Emerald Publishing Limited [ISSN 0003-5599] [DOI 10.1108/ACMM-09-2019-2176] Received 4 September 2019 Revised 20 October 2019 Accepted 23 October 2019 38