Abstract:
Two-dimensional (2D) MXenes, also referred to as transition metal carbides/nitrides,
exhibit electrocatalytic water-splitting applications due to their unique characteristics. These
include a layered structure, high density, metallic-like conductivity, and functional surface
groups that help to achieve efficient water splitting for the generation of clean and
sustainable hydrogen energy.
This study presents a comprehensive experimental investigation focusing on two different
MXenes namely, V2CTx and Ti3C2Tx, and their corresponding nanocomposites, Er@V2CTx
and Er@Ti3C2Tx, for their suitability for water-splitting applications. The electrochemical
behaviour of the Er@V2CTx and Er@Ti3C2Tx nanocomposites, with varying percentages of
Er incorporated into vanadium carbide and titanium carbide MXene matrices, is extensively
studied and discussed. Electrochemical testing was conducted in an alkaline medium (1M
KOH) to evaluate hydrogen evolution reaction (HER) and oxygen evolution reaction (OER)
potential.
The Er@V2CTx nanocomposite exhibited a redox potential of 174 mV at a current density
of 10 mA/cm2, with a Tafel slope of 107 mV/dec for HER. Similarly, the Er@Ti3C2Tx
nanocomposite demonstrated an overpotential of 256 mV at 10 mA/cm2 current density,
with a Tafel slope of 102 mV/dec for HER. For the OER, the Er@V2CTx nanocomposite
exhibited an overpotential of 370 mV at 10 mA/cm2 current density, with a Tafel slope of
131 mV/dec, while the Er@Ti3C2Tx nanocomposite showed an overpotential of 381 mV at
10 mA/cm2 current density, with a Tafel slope of 157 mV/dec. The structure and
morphology of the compounds were examined using techniques such as X-ray diffraction
(XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS),
Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy, confirming the
successful formation of the nanocomposites while retaining the desirable two-dimensional
(2D) structure of MXene.
