Abstract:
The development of effective and sustainable strategies for energy conversion and carbon dioxide
(CO₂) reduction is pivotal in tackling pressing global energy and environmental issues. This
research focuses on a novel heterojunction composed of titanium carbide (Ti₂C) MXene and nickel
telluride (NiTe), designed for photoelectrochemical (PEC) water splitting and CO₂ reduction
applications. The synthesized material was thoroughly characterized using several techniques,
including Powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy
Dispersive X-Ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), Raman
Spectroscopy, UV-Visible Diffuse Reflectance Spectroscopy (DRS), X-Ray Photoelectron
Spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area analysis, and Fourier Transform
Infrared Spectroscopy (FTIR). TEM analysis revealed that the NiTe structure exhibited needle
like features extending from the 2D sheets of Ti₂C MXene, indicating robust interfacial interactions
and confirming the successful formation of the heterojunction. The Ti₂C-NiTe heterostructure,
referred to as MNT, demonstrated superior performance metrics, including the lowest charge
transfer resistance (RCT), reduced band gap, and the highest photocurrent density. Specifically,
the MNT heterojunction achieved an impressive photocurrent density of 11.7 mA cm⁻² at 1.8556
V vs. RHE, with an RCT value of 422.3 Ω, a flat band potential (VFB) of 0.79 V, and an extended
electron lifetime of 1.97 milliseconds. Additionally, it exhibited a specific surface area of 31.629
m²/g, a band gap of 2.94 eV, and notable CO₂ reduction activity, producing carbon monoxide at a
rate of 5.173 mmol g⁻¹ h⁻¹ and methane at 0.214 mmol g⁻¹ h⁻¹ at 400 °C. These results indicate the
successful formation of a Schottky heterojunction, which enhances charge carrier mobility and
minimizes charge recombination by establishing a Schottky barrier.
