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Photocatalytic Hydrogen Production of Semiconductor Nano-crystal-based Hydrogels

Photocatalytic Hydrogen Production of Semiconductor Nano-crystal-based Hydrogels

Investigation of nanocrystal-based gel structures

Hydrogen is a widely discussed alternative to fossil fuels and besides the yet industrially applied electrolysis, photocatalytic hydrogen production could be a method to supply hydrogen. A variety of materials, e.g., TiO2, MoS2, CdS, SiC or g-C3N4, has been investigated to find a suitable candidate to use sunlight efficiently for photocatalytic hydrogen production. Nanomaterials in comparison to the bulk material in general provide a large surface-to-volume ratio leading to a high amount of catalytically active surface in an overall low amount of material. To broaden the possible applications of these nanomaterials a novel class of materials with an interesting morphology are nanocrystal-based gel structures. Nanocrystal-based gel structures undergo a controlled destabilization of the ligand-stabilized nanocrystal solution to form a three-dimensional, highly porous network which retains the properties of the nanocrystal building blocks.

In this work, we present the influence of gel network formation of different semiconductor nanocrystal building blocks on the photocatalytic hydrogen production in aqueous solutions in comparison to their nongelated nanocrystal building block counterparts. As semiconductor material beside others a heterostructure made of a CdSe core with a CdS rod like shell. To destabilize the ligand-stabilized nanocrystal solutions, an oxidative method using H2O2 was used. Removal of the ligands from the surface leads to the formation of a hydrogel with more freely accessible surface and different surface properties, such as the formation of sulfate sites, compared to the ligand-stabilized nanocrystals.

Original article:

J. Schlenkrich, F. Lübkemann-Warwas, R. T. Graf, C. Wesemann, L. Schoske, M. Rosebrock, K. D. J. Hindricks, P. Behrens, D. W. Bahnemann, D. Dorfs, and N. C. Bigall: Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal-Based HydrogelsSmall 2023, 2208108
DOI: 10.1002/smll.202208108