Bridged Polystannoxane: A New Route toward Nanoporous Tin Dioxide

Abstract

Hydrolysis and condensation under acidic conditions of bis(triprop-1-ynylstannyl)p-phenylene 1, p-xylene 2, or butylene 3 precursors yielded bridged polystannoxanes in the form of xerogels after being dried under reduced pressure. The gels were amorphous and nonporous with very low specific surface areas. Thermal treatment of the xerogels in air at 400-500°C resulted in nanocrystalline nanoporous cassiterite tin dioxide materials, which have been thoroughly characterized by elemental analysis, FTIR, TGA-MS, powder XRD, and N 2 adsorption porosimetry. The calcined materials consisted of a porous network of aggregated nanoparticles with a nanoporosity stemming from the interparticle space. A careful tuning of the precursor nature and the calcination conditions enabled the synthesis of materials with BrunauerEmmet-Teller surface areas ranging from 40 to 150 m 2 g -1 , a mean pore size between 3.5 and 12 nm, and an average particle size of 5 to 25 nm. Starting from precursor 1 appeared to be the best strategy to obtain pure nanocrystalline tin dioxide materials with good textural properties for applications, with the p-phenylene bridge being easily removed by calcination.

Improved Electrochemical Performance of Tin Dioxide Using a Tin Phosphate-Based Coating

“…The isotherms ͑not shown͒ of tin dioxide samples with nonnegligible surface area exhibit a type-IV behavior and type-H2 hysteresis loop ͑IUPAC classification͒ that is typical of the existence of mesopores, in good agreement with previous studies. 12 The pores tend to collapse upon annealing at high temperature. The phosphate shell changes the surface properties of the resulting particles.…”

Nanostructured Materials

“…83 Materials with alternate layers of SnO 2 /hydrophobic material have also been synthesized. It is therefore necessary to resort to other precursors to obtain an adjustable solid by inorganic polymerization (solgel).…”

Precursors for the Formation of Tin(IV) Oxide and Related Materials

“…65 When xerogels derived from hydrolysis of O 1.5 SnC 6 H 4 SnO 1.5 are calcined in air at 400-500 °C, the bridging phenylene group is easily removed resulting in nanocrystalline nanoporous cassiterite SnO 2 with tunable surface area. 66 An analogous strategy has been used to elaborate and functionalise the surface of SnO 2 particles, by hydrolysis of XSn(CºCR) 3 in the presence of the nanoparticles, which resulted in attachment of XSn to the oxide surface. In this way, fluorinated chains [X = (CF 2 ) 7 CF 3 ] or dyes [X = (CH 2 ) n perylene, n = 2, 4], for applications in self-cleaning coatings and photovolataic devices, respectively, 67,68 have been prepared.…”