New hydrogen-producing photocatalysts—A combinatorial search

A high-throughput (HT) method for the discovery of new heterogeneous catalysts for photocatalytic hydrogen production from aqueous methanol solutions is presented. The HT workflow includes the preparation of libraries containing multi-component metal oxides following a modified sol–gel route, the irradiation of catalyst suspensions with a custom illumination setup and fast sequential product gas analysis by gas chromatography to evaluate catalyst performance. The influence of reaction parameters, as e.g. catalyst grain size, light intensity on the results is discussed. Results of the screening of diverse mixed metal oxide libraries are shown. An evolutionary search strategy involving doping of active oxides and screening of variations in material compositions was applied to discover new photocatalysts. As a new lead structure, an aluminium–lead–bismuth-oxide has been discovered. Further activity increases have been achieved through doping.