Unveiling the HER potential of TM-substituted PdTe₂ monolayers: a first-principles study

Area of Science:

• Materials Science
• Computational Chemistry
• Electrochemistry

Background:

• The hydrogen evolution reaction (HER) is crucial for clean energy production.
• Developing efficient and cost-effective electrocatalysts is essential for HER.
• Pentagonal PdTe2 monolayers are explored for catalytic applications.

Purpose of the Study:

• To investigate the catalytic capability of pentagonal PdTe2 monolayers for HER.
• To enhance the HER activity of PdTe2 through transition metal substitution.
• To understand the underlying mechanisms of improved catalytic performance.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Phonon spectra analysis for dynamical stability.
• Ab initio molecular dynamics (AIMD) simulations for thermal robustness.
• Total and partial density of states (TDOS/PDOS) and band structure analysis.
• Work function analysis.
• Kinetic analysis of the HER mechanism.

Main Results:

• Pristine PdTe2 exhibits limited HER activity with a high overpotential (1.38 V).
• Mo and Ti substitutions significantly reduce the overpotential to 50 mV and 90 mV, respectively.
• Substituted PdTe2 monolayers demonstrate structural and thermal stability.
• Doping induces spin polarization, enhances metallicity, and improves electronic states at the Fermi level.
• Kinetic analysis reveals favorable activation energy barriers for the Tafel step.

Conclusions:

• Mo- and Ti-substituted PdTe2 monolayers are promising candidates for efficient HER electrocatalysts.
• These materials offer comparable performance to platinum, a benchmark catalyst.
• The findings suggest potential for noble metal-free HER electrocatalysis.