Hydrogen evolution reaction evidenced for Mo₂O₂S₂-thiosemicarbazone coordination complexes.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Electrochemistry

Background:

• The development of efficient catalysts for hydrogen evolution reaction (HER) is crucial for sustainable energy technologies.
• Molybdenum-sulfur clusters offer promising structural motifs for catalytic applications.
• Understanding the influence of ligand design and complex nuclearity on catalytic activity is essential.

Purpose of the Study:

• To synthesize and characterize a series of dinuclear and tetranuclear molybdenum-sulfur complexes.
• To evaluate the HER performance of these complexes in aqueous media across a pH range of 1-4.
• To elucidate the catalytic mechanism using computational methods.

Main Methods:

• Synthesis and characterization of novel dinuclear and tetranuclear molybdenum-sulfur complexes.
• Electrochemical studies of modified electrodes incorporating the synthesized complexes.
• Density Functional Theory (DFT) calculations to investigate the reaction mechanism.

Main Results:

• A family of 7 dinuclear and tetranuclear complexes based on the [Mo2O2S2]2+ core and bis-thiosemicarbazone ligands were synthesized.
• The complexes exhibited catalytic activity for HER in aqueous solution within the pH range of 1-4.
• DFT studies revealed a Volmer-Tafel mechanism, detailing key protonation and reduction steps.

Conclusions:

• Ligand variation and complex nuclearity significantly impact HER performance.
• The elucidated mechanism provides insights into the catalytic cycle involving molybdenum hydride intermediates.
• These complexes represent potential candidates for electrocatalytic hydrogen production.