Selective surfaces: High-surface-area zinc tin sulfide chalcogels

Porous zinc tin sulfide aerogel materials were constructed by metathesis reactions between Zn(acac)₂•H₂O and tetrahedral thiostannate cluster salts containing discrete [SnS₄]^4-, [Sn₂S₆]^4-, and [Sn₄S 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 ₂Sn_xS_2x+2 (x = 1, 2, 4) aerogels showed high surface areas (363-520 m²/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.