2026/03/30 by Narender Kumar, Shambhu Bhandari, Dario Alfè +2 · 1 voice
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.apsusc.2026.167411
arxiv published 2026/03/30 · arxiv updated 2026/06/02
This investigation demonstrates that the pentagonal PdTe2 (penta-PdTe2) monolayer is a highly tunable two-dimensional (2D) photocatalyst, characterized by a bandgap of 1.87~eV and high hole mobility. Using density functional theory (DFT) calculations with the HSE06 functional, we show that tensile strain engineering, particularly at +2% and +3%, is essential for enabling spontaneous water splitting. At these strain values, the valence-band maximum (VBM) and conduction-band maximum (CBM) straddle the water redox potentials (H+/H2 and O2/H2O) under both acidic (pH=0) and neutral (pH=7) conditions. The monolayer's low hole effective mass facilitates rapid charge extraction, mitigating electron--hole recombination and promoting the oxygen evolution reaction (OER) more effectively than many hexagonal and pentagonal counterparts. The Gibbs free energy (ΔG) pathways indicate that the overpotentials for the hydrogen evolution reaction (HER) and OER are highly sensitive to mechanical deformation, specifically biaxial strain. In particular, a tensile strain of +3% yields an optimized balance of overpotentials, with ηHER = 0.70~V at pH=0 and ηOER = 0.72~V at pH=7. Finally, integrating optical absorption with thermodynamic driving forces results in a solar-to-hydrogen (STH) efficiency of 20.40% at pH=7. This performance exceeds that of several previously reported two-dimensional catalysts, positioning penta-PdTe2 as a superior candidate for sustainable, solar-driven hydrogen production.