Phys.org March 26, 2024
To understand the factors that promote bimetallic H–H coupling researchers at the University of North Carolina at Chapel Hill, USA, subjected molecular iridium catalysts to undergo photoelectrochemical dihydrogen (H2) evolution via a bimolecular mechanism. Covalently tethered diiridium catalysts evolved H2 from neutral water faster than monometallic catalysts, even at lower overpotential. The unexpected origin of this improvement was non-covalent supramolecular self-assembly into nanoscale aggregates that efficiently harvested light and form H–H bonds. Monometallic catalysts containing long-chain alkane substituents leveraged the self-assembly to evolve H2 from neutral water at low overpotential and with rates close to the expected maximum for this light-driven water splitting reaction. According to the researchers their work shows the design parameters for holding multiple catalytic sites in proximity and tuning catalyst microenvironments…read more. TECHNICAL ARTICLE
Mechanisms of H2 evolution. Credit: Nature Chemistry, 25 March, 2024