Visible Light-Driven H2 Production by Hydrogenases Attached to Dye-Sensitized TiO2 Nanoparticles

Abstract

A study of hybrid, enzyme-modified nanoparticles able to produce H₂ using visible light as the energy source has been carried out to establish per-site performance standards for H₂ production catalysts able to operate under ambient conditions. The [NiFeSe]-hydrogenase from Desulfomicrobium baculatum (Db [NiFeSe]-H) is identified as a particularly proficient catalyst. The optimized system consisting of Db [NiFeSe]-H attached to Ru dye-sensitized TiO₂, with triethanolamine as a sacrificial electron donor, produces H₂ at a turnover frequency of approximately 50 (mol H₂) s⁻¹ (mol total hydrogenase)⁻¹ at pH 7 and 25 °C, even under the typical solar irradiation of a northern European sky. The system shows high electrocatalytic stability not only under anaerobic conditions but also after prolonged exposure to air, thus making it sufficiently robust for benchtop applications.