A Stable Alkylated Cobalt Catalyst for Photocatalytic H2 Generation in Liposomes. Issue 20 (18th August 2022) - Klein, David M.
Abstract: Photocatalytic proton reduction is a promising way to produce dihydrogen (H2 ) in a clean and sustainable manner, and mimicking nature by immobilising proton reduction catalysts and photosensitisers on liposomes is an attractive approach for biomimetic solar fuel production in aqueous solvents. Current photocatalytic proton reduction systems on liposomes are, however, limited by the stability of the catalyst. To overcome this problem, a new alkylated cobalt(II) polypyridyl complex (CoC12 ) was synthesised and immobilised on the lipid bilayer of liposomes, and its performance was studied in a photocatalytic system containing an alkylated ruthenium photosensitiser (RuC12 ) and a 1 : 1 mixture of sodium ascorbate and tris‐2‐carboxyethylphosphine hydrochloride as sacrificial electron donors. Several parameters (concentration of CoC12 and RuC12, pH, membrane composition) were changed to optimise the turnover number for H2 production. Overall, CoC12 was found to be photostable and the optimised turnover number (161) was limited only by the decomposition of the ruthenium‐based photosensitiser. Abstract : Artificial photosynthesis : A novel amphiphilic cobalt(II) polypyridyl complex (CoC12 ) and an amphiphilic ruthenium photosensitiser (RuC12 ) were immobilised on liposomes to perform photocatalytic H2 generation in the presence of ascorbate (Hasc − ) and tris‐2‐carboxyethylphosphine hydrochloride (TCEP ) as sacrificial electron donors. In such conditions, CoC12 was found to be photostable, while the optimised turnover number (161) was limited by the decomposition of the ruthenium‐based photosensitiser.