Ionic-Liquid-Assisted Precursor Route Syntheses of Highly Dispersed Supertetrahedral T3 In-S/Se Clusters for Photocatalytic Hydrogen Production

Herein, two pure inorganic isostructural supertetrahedral T3 cluster based compounds with different ratio of S : Se, namely [Bmmim](6)[In(10)QCl(4)](MIm)(2) (Q=S9.5Se6.5 (In-S/Se-1), S2Se14 (In-S/Se-2), Bmmim=1-butyl-2,3-dimethylimidazolium, MIm=1-methylimidazole), have been obtained via an ionic-liquid-auxiliary precursor approach. Single-crystal X-ray diffraction (SCXRD) characterization showed that their structures are comprised of a discrete supertetrahedral T3 [In(10)QCl(4)](6-) cluster charge-balanced via six [Bmmim](+) cations. Importantly, the T3 clusters of In-S/Se-1 and In-S/Se-2 can be highly dispersed in dimethyl sulfoxide (DMSO). As a result, the T3 clusters uncovered more active sites after being dispersed, thereby exhibiting similar to 6 times of hydrogen generation rate of that in the solid state. Furthermore, benefitting from higher visible-light absorption, larger driving force from conduction band (CB) and rapider photogenerated carrier migration, the photocatalytic H-2 evolution activity was monotonically improved with increasing of the Se concentration in the T3 clusters. This work provides an alternative strategy for obtaining novel hybrid metal chalcogenide crystalline compounds for efficient energy conversion.