Full water splitting into hydrogen and oxygen on semiconductor nanocrystals is a challenging task; overpotentials must be overcome for both half-reactions and different catalytic sites are needed to facilitate them. Additionally, efficient charge separation and prevention of back reactions are necessary. Here, we report simultaneous H2 and O2 evolution by CdS nanorods decorated with nanoparticulate reduction and molecular oxidation co-catalysts. The process proceeds entirely without sacrificial agents and relies on the nanorod morphology of CdS to spatially separate the reduction and oxidation sites. Hydrogen is generated on Pt nanoparticles grown at the nanorod tips, while Ru(tpy)(bpy)Cl2-based oxidation catalysts are anchored through dithiocarbamate bonds onto the sides of the nanorod. O2 generation from water was verified by 18O isotope labelling experiments, and time-resolved spectroscopic results confirmed efficient charge separation and ultrafast electron and hole transfer to the reaction sites. The system demonstrates that combining nanoparticulate and molecular catalysts on anisotropic nanocrystals provides an effective pathway for visible-light-driven photocatalytic water splitting.
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This work was supported by the Bavarian State Ministry of Science, Research, and Arts through the grant ‘Solar Technologies go Hybrid (SolTech)’ and the ERANETMED programme (project Hydrosol, grant no. ENERG-11-132). The authors thank C. Hohmann (Nanosystems Initiative Munich) for his support with graphics design. P.D.F. thanks the Alexander von Humboldt Foundation for a postdoctoral fellowship.
The authors declare no competing interests.
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Wolff, C.M., Frischmann, P.D., Schulze, M. et al. All-in-one visible-light-driven water splitting by combining nanoparticulate and molecular co-catalysts on CdS nanorods. Nat Energy 3, 862–869 (2018). https://doi.org/10.1038/s41560-018-0229-6
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