DOI: 10.34810/data1750
title: Replication data for "Hydrogen Evolution Reaction of Electrodeposited Ni-W Films in Acidic Medium and Performance Optimization Using Machine Learning"

description: Experimental raw data for all figures presented in the paper "Hydrogen Evolution Reaction of Electrodeposited Ni-W Films in Acidic Medium and Performance Optimization Using Machine Learning" are provided. The data were utilized to investigate and optimize the electrodeposition conditions of Ni-W films for hydrogen evolution reaction (HER) using machine learning. The study began with an analysis of bath and electrodeposition conditions (Figure 1), followed by SEM imaging of the film morphologies at several current densities and temperatures (Figure 2). The crystal structure of the films was characterized by GIXRD (Figure 3), and the electrocatalytic properties were tested (Figures 4, 5). Additionally, the durability of the films in acidic media was assessed (Figures 6, 7). Subsequently, machine learning was employed to optimize the deposition conditions (ML data). The best-performing samples were further analysed using SEM, TEM, electrochemical measurements (Figures 8, 9), XPS (Figure 11), and XRD (Figure 12) to evaluate the optimized film properties both before and after HER testing.
description: Description of methods used for collection-generation of data - Methodology for Ni-W Film Electrodeposition and Electrochemical Testing Dataset: This dataset comprises electrochemical synthesis and activity testing data for Ni-W films electrodeposited using a double-jacketed, three-electrode cell coupled to a 302N Autolab potentiostat/galvanostat. A double junction Ag/AgCl reference electrode with 3 M KCl and 1 M Na2SO4 solutions was used as the reference electrode (RE), and a platinum wire spiral served as the counter electrode (CE). Ni-W films were grown on metallized silicon (111) substrates with sputter-coated Ti (10 nm)/Au (90 nm) layers. The electrolyte, adapted from Bera et al., contains 0.11 M NiSO4·7 H2O, 0.05 M Na2WO4·2 H2O, 0.5 M sodium gluconate, and 0.65 M H3BO3 in Milli-Q (MQ) water. Adjustments included an increased tungstate concentration (0.11 M) or a fourfold decrease in all chemical concentrations. The pH of the bath was set to 5.0, and deposition temperatures ranged between 25°C and 65°C, with periodic water replenishment to counteract evaporation. The electrolyte was de-aerated with N2, with a continuous N2 blanket maintained over the solution. Electrochemical deposition was performed galvanostatically at current densities of −1 to −40 mA/cm², with magnetic stirring at 100 rpm. Cyclic voltammetry (CV) characterized the electrolyte prior to deposition, with a scan rate of 50 mV/s. Electrochemical Activity Testing - The HER activity of the as-deposited Ni-W coatings was tested in 0.5 M H2SO4 at 25°C, using a graphite counter electrode and the Ni-W films as the working electrode. Linear sweep voltammetry (LSV) was conducted from OCP to −0.6 V vs RHE, with potentials converted to RHE according to E(RHE) = E(Ag/AgCl) + 0.210 V + 0.059 V pH. Electrocatalytic surface area (ECSA) was determined by cycling the electrode in the non-faradaic region at scan speeds from 1 to 50 mV/s.
Instrument ( or software) specific information needed to interpret the data - Fig. 1: SEM micrographs: any image viewer, Fig. 2, XRD: MAUD, Figs. 4, 5 and 7: any spreadsheet software. Instruments, calibration and standards information - Electrochemical measurements: Autolab 302N potentiostat with Ag/AgCl (3 M KCl) reference electrode
SEM: Zeiss Merlin with InLens detector XRD: Malvern-PANalytical X’pert Pro diffractometer with Cu Kα radiation. Environmental or experimental conditions - atmospheric influences.