Photoelectrocatalytic H2 evolution from integrated photocatalysts adsorbed on NiO

摘要

A new approach to increasing the faradaic efficiency of dye-sensitised photocathodes for H2 evolution from water, using integrated photocatalysts, furnished with ester groups on the peripheral ligands, [Ru(decb)2(bpt)PdCl(H2O)](PF6)2 (>1) and [Ru(decb)2(2,5-bpp)PtI(CH3CN)](PF6)2 (>2), (decb = 4,4′-diethylcarboxy-2,2′-bipyridine, bpp = 2,2':5′,2′′-terpyridine, bpt = 3,5-bis(2-pyridyl)-1,2,4-triazole) is described. Overall, >1|NiO is superior to previously reported photocathodes, producing photocurrent densities of 30–35 μA cm^–2 at an applied bias of –0.2 V vs. Ag/AgCl over 1 hour of continuous white light irradiation, resulting in the generation of 0.41 μmol h^–1 cm^–2 of H2 with faradaic efficiencies of up to 90%. Furthermore, surface analysis of the photocathodes before and after photoelectrocatalysis revealed that the ruthenium bipyridyl chromophore and Pd catalytic centre (>1) were photochemically stable, highlighting the benefits of the approach towards robust, hybrid solar-to-fuel devices.