Selective Surfaces: High-Surface-Area Zinc Tin Sulfide Chalcogels

Porous zinc tin sulfide aerogel materials were constructed by metathesis reactions between Zn(acac)(2)center dot H(2)O and tetrahedral thiostannate cluster salts containin discrete [SnS(4)](4-), [Sn(2)S(6)](4-) and [Sn(4)S(10)](4-) units. Self-assembly reactions of the Zn(2+) linker and anionic thiostannate clusters yielded polymeric random Zn/Sn/S networks with gelation properties. Supercritical drying of the gels and solvent/counterion removal resulted in a metal sulfur framework. Zn(2)Sn(x)S(2x+2) (x = 1, 2, 4) aerogels showed high surface areas (363-520 m(2)/g) and pore volumes (1.1-1.5 cm(3)/g), and wide bandgap energies (2.8-3.2 eV). Scanning and transmission electron microscopy studies show the pores are micro- (d < 2 nm), meso- (2 nm < d < 50 nm), and macro- (d > 50 nm) regions. The zinc chalcogenide aerogels also possess high affinities toward soft heavy metals and reversible absorption of strong electron-accepting molecules.