Chemical Engineering Journal 452 (2023) 139523 Available online 3 October 2022 1385-8947/© 2022 Elsevier B.V. All rights reserved. WS 2 -embedded MXene/GO hybrid nanosheets as electrodes for asymmetric supercapacitors and hydrogen evolution reactions Sajjad Hussain a, b , Dhanasekaran Vikraman c , Zulfqar Ali Sheikh d , Muhammad Taqi Mehran e , Faisal Shahzad f , Khalid Mujasam Batoo g , Hyun-Seok Kim c , Deok-Kee Kim d , Muhammad Ali h, * , Jongwan Jung a, b, * a Hybrid Materials Center (HMC), Sejong University, Seoul 05006, Republic of Korea b Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea c Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea d Department of Electrical Engineering, Sejong University, Seoul 05006, Republic of Korea e School of Chemical and Materials Engineering, National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan f National Center for Nanotechnology, Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad 45650, Pakistan g College of Science, King Saud University, P.O. Box-2455, Riyadh 11451, Saudi Arabia h Interdisciplinary Research Center for Hydrogen and Energy Storage (IRC-HES), King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia A R T I C L E INFO Keywords: DFT Supercapacitors WS 2 MXene HER Composites ABSTRACT MXene-related materials are auspicious electrodes for energy storage/conversion application due to their various features, including large surface area, high metallic conductivity, and fast redox activity; however, their surface aggregation and oxidation have significantly restricted their application in various industries. This study demonstrated the fabrication of porous WS 2 nanosheets-interconnected MXene/GO (WS 2 @MXene/GO) nano- composites using a simple hydrothermal reaction for electrochemical supercapacitors and water splitting re- actions. The assembled WS 2 @MXene/GO nanocomposites electrode produced a superior specific capacitance of ~ 1111F g  1 at 2 A/g applied current. Further, the asymmetric device constructed using the nanocomposite delivered the high specific energy of ~ 114 Wh kg  1 and asymmetric capacitance of 320F g  1 along with an exceptional cycling stability. The WS 2 @MXene/GO nanocomposites electrocatalyst exhibited low overpotentials of 42 and 45 mV and small Tafel slopes values of 43 and 58 mV.dec  1 for hydrogen evolution reaction in acidic and alkaline medium, respectively. In addition, density functional theory (DFT) approximations validated the observed experimental results using density of states, Gibbs free energy for H-adsorption, and quantum capac- itance calculations. 1. Introduction To achieve a clean environment, meet the demand of alternatives to traditional fossil fuels, and address climate warming issue, numerous works have been completed to advance sustainable, green, and renew- able energy resources and storage technologies [1,2]. Electrochemical water splitting is known as a capable and viable process, and it involves the use of electrical energy for the production of H 2 through electrolysis reaction [3,4]. Precious metals, such Pt and its derivative-based alloys catalysts, are considered as the most electroactive catalyst for hydrogen evolution reaction (HER). However, the rich price and scarcity of Pt have stalled its widespread practical applications. Hence, sustainable energies have been dedicated to explore earth-abundance and inex- pensive alternatives to Pt-based catalysts. Similarly, supercapacitors, an excessive energy storage technology, exhibit not only energy storage behavior like conventional batteries, but also exhibit attractive features such as rapid charging, long lifetimes, safety, high power density and superb low-temperature adaptability for electric vehicles, electronic devices, and distinct industrial applications [5–7]. Typically, the per- formance of supercapacitors are primarily associated with electrodes materials, and various multifarious materials, including metal oxides, transition metal di-chalcogenides (TMDs), carbon and their derivatives, * Corresponding authors at: Hybrid Materials Center (HMC), Sejong University, Seoul 05006, Republic of Korea (Jongwan Jung). E-mail addresses: muhammad.ali@kfupm.edu.sa (M. Ali), jwjung@sejong.ac.kr (J. Jung). Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej https://doi.org/10.1016/j.cej.2022.139523 Received 13 June 2022; Received in revised form 25 September 2022; Accepted 28 September 2022