Synthesis, Characterization and Application of Metal-Chalcogenide Aerogel

This dissertation presents the results of synthesizing metal-chalcogenide aerogel, its characterization, and other experiments that reveal unique functionalities. The purpose of this work is: (1) to expand the currently established metathesis route of metal-chalcogenide aerogel synthesis by adopting new building blocks with proper synthetic adjustments, (2) to demonstrate the reasonable steps of characterizations to understand the structural and functional identities of the resulting aerogel, and (3) to investigate the potential applications of the metal-chalcogenide aerogel's unique properties.;The successful synthesis of aerogel using Zn2+ and [Sn xS2x+2]4- (x = 1, 2, 4) demonstrates that alternating kinetic factors can affect the outcome of self-assembly reactions between inorganic building blocks. In order to synthesize metal-chalcogenide aerogel, a porous gel network must be produced through a slow-assembly reaction between transition metal ions and chalcogenide cluster ions. In the presence of chalcogenide cluster ions, light transition metal (e.g. zinc) precursors with various monodentate ligands (e.g. acetate, nitrate, sulfate) tend to react rapidly, forming precipitation. Zinc tin sulfide aerogel is the first metal-chalcogenide system synthesized from metal precursors with bidentate ligands; it reduces the self-assembly reaction of zinc ions so that a gel network can be established. The resulting zinc tin sulfide wet gel can be transformed into a highly porous aerogel, possessing accessible sulfidic surfaces that can selectively remove soft heavy metal ions from aqueous solutions.;The synthetic method of creating zinc chalcogel can be adapted to using Fe2+ and [SnS4]4- building blocks to form gel that becomes the backbone of iron chalcogenide aerogel. Iron-tin-sulfide aerogel exhibits unexpected superparamagnetic behavior in its amorphous network. Our thorough characterizations demonstrate the intrinsic magnetism of the amorphous iron aerogel.;Platinum polysulfide aerogels are excellent for demonstrating the unique functionalities that arise when the chalcogenide surface meets a porous structure. The series of polysulfide chains ([Sx]2- (x = 3, 4, 5, 6) form a monolithic wet gel network with Pt2+ in formamide solution. Supercritically dried platinum polysulfide networks feature ion-exchangeable anionic networks (charge balanced with potassium) and accessible S-S bonding sites capable of air-borne heavy metal waste capture (Hg o). These properties make platinum chalcogenide aerogels useful for environmental remediation.