The production of hydrogen fuels, via water splitting, is of practical relevance for meeting global energy needs and mitigating the environmental consequences of fossil-fuel-based transportation. Water photoelectrolysis has been proposed...

High throughput theoretical methods are increasingly used to identify promising photocatalytic materials for hydrogen generation from water as a clean source of energy. While most promising water splitting candidates require co-catalyst loading and electrical biasing, computational costs to predict them apriori becomes large. It is therefore important to identify bare, bias-free semiconductor photocatalysts with small initial hydrogen production rates, often in the range of tens of nano-mols per hour, as these can become highly efficient with further co-catalyst loading and biasing. Here we report a sensitive hydrogen detection system suitable for screening new photocatalysts. The hydrogen evolution rate of the prototypical rutile TiO 2 loaded with 0.3 % wt Pt is detected to be 78.0±0.8 µmol/h/0.04g, comparable with the rates reported in literature. In contrast, sensitivity to an ultralow evolution rate of 11.4±0.3 nmol/h/0.04g is demonstrated for bare polycrystalline TiO 2 without electrical bias. Two candidate photocatalysts, ZnFe 2 O 4 (18.1±0.2 nmol/h/0.04g) and Ca 2 PbO 4 (35.6±0.5 nmol/h/0.04g), without electrical bias or co-catalyst loading, are demonstrated to be potentially superior to bare TiO 2 . This work expands the techniques available for sensitive detection of photocatalytic processes towards much faster screening of new candidate photocatalytic materials in their bare state.

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