Hydrogen evolution reaction by Gd-doped transition metal dichalcogenide VSe2 nanoflowers

Abstract

Renewable energy sources, such as hydrogen, are helpful in reducing the dependence on fossil fuels. Electrocatalytic water splitting produces hydrogen, which is a cleaner and more reliable energy source than fossil fuels. The number of exposed active sites in a catalyst considerably affects its catalytic activity. Recently, transition-metal dichalcogenides have been widely investigated for their electrochemical performance. In this context, we prepared Gd-doped VSe₂ nanocomposites V_1−xGd_xSe₂ (x = 0, 0.2, and 0.3) using a simple and inexpensive hydrothermal method for the catalytic hydrogen evolution reaction (HER). The prepared sample possessed a nanoflower-like surface morphology with an increase in bandgap from 2.6 to 3.6 eV by Gd doping. The Gd-doped samples showed significantly better electrochemical properties than the pure VSe₂ sample. The highest Gd-doped sample showed the highest electrochemical performance, with an onset potential around 210 mV and a low value of the Tafel slope of around 60 mV per decade, with respect to other samples. This sample also showed a low charge-transfer resistance value of around 1.30 kΩ (calculated from impedance data), which showed good agreement with the HER polarization data and Tafel plot.