Impact of the Type of Reactor and the Catalytic Conditions on the Photocatalytic Production of Hydrogen Using a Fully Noble-Metal-Free System

For efficient photocatalytic hydrogen production not only the photocatalytic system itself, but also the reactor design and appropriate catalytic conditions play a central role for achieving high overall activity and long lifetimes. To investigate these points further, a fully noble-metal-free system for the light-driven reduction of protons to hydrogen, consisting of a copper photosensitizer and an iron carbonyl catalyst, was chosen as a model. The traditional batch reactor was replaced by a semi-batch photoreactor with a continuously perfused gas phase in combination with in situ gas chromatography. This allowed for the time resolved analysis of all gases formed and enabled a systematic investigation of the impact of different light sources, light intensities and carrier gases. The results revealed a significant change in activity due to CO removal from the catalyst caused by the continuous gas flow. This effect can be counteracted by supplying additional CO through the gas phase.