A noble metal-free photocatalytic system based on a novel cobalt tetrapyridyl catalyst for hydrogen production in fully aqueous medium

Abstract

The new cobalt tetrapyridyl complex 1(BF₄)₂ was characterized and assessed for hydrogen production in fully aqueous solution. Mechanistic information was gained thanks to a fast screening method, using chemical reductants and a Clark microelectrode. Optimal hydrogen production (443 TONs – 3 mL of H₂) was achieved under visible light-driven conditions, in the presence of a noble metal-free photosensitizer, the water soluble porphyrin 2Cl₄, and the ascorbate/tris-(2-carboxyethyl)phosphine (TCEP) sacrificial electron donor system.