Ultrasensitive electrode-free and co-catalyst-free detection of nanomoles perhour hydrogen evolution for the discovery of new photocatalysts

• Published in: Review of scientific instruments 2022-02, Vol.93 (2)
• Main Authors: Wang, Huaiyu, Katzbaer, Rowan R, Fanghanel Julian, Schaak, Raymond E, Venkatraman, Gopalan
• Format: Article
• Language: English
• Subjects: Bias; Catalysts; Clean energy; Energy sources; Hydrogen; Hydrogen evolution; Hydrogen production; Photocatalysis; Photocatalysts; Scientific apparatus & instruments; Screening; Titanium dioxide; Water splitting
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/5.0077650

High throughput theoretical methods are increasingly used to identify promisingphotocatalytic materials for hydrogen generation from water as a clean source of energy.While most promising water splitting candidates require co-catalyst loading and electricalbiasing, computational costs to predict them a priori become large. Itis, therefore, important to identify bare, bias-free semiconductor photocatalysts withsmall initial hydrogen production rates, often in the range of tens of nanomoles 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 TiO2 loaded with 0.3wt. % Pt is detected to be 78.0 ± 0.8 µmol/h/0.04 g, comparable with therates reported in the literature. In contrast, sensitivity to an ultralow evolution rateof 11.4 ± 0.3 nmol/h/0.04 g is demonstrated for bare polycrystalline TiO2without electrical bias. Two candidate photocatalysts, ZnFe2O4 (18.1± 0.2 nmol/h/0.04 g) and Ca2PbO4 (35.6 ± 0.5 nmol/h/0.04 g) withoutelectrical bias or co-catalyst loading, are demonstrated to be potentially superior tobare TiO2. This work expands the techniques available for sensitive detectionof photocatalytic processes toward much faster screening of new candidate photocatalyticmaterials in their bare state.