Surfactantless synthesis and textural properties of self-assembled mesoporousSnO2

Abstract

Ordered surfactantless self-assembled, mesoporousSnO2 adsorbents, consisting of tubular voids of nanometric sizes, areprepared by the sol–gel processing of tin (IV) tetra-tert-amyloxide,Sn(OAmt)4, whose molecules have been previously chelated with acetylacetone in the absence of water,to modulate their reactivity and to promote an incipient self-assembling of –O–Sn–O oligomericspecies; ultimately, the necessary amount of water to induce the hydrolysis–condensationreactions is added to this aged sol, then producing tubular pore templates within theSnO2 xerogel network. Acollection of mesoporous SnO2 xerogels of assorted structural properties has been obtained aftercalcination in air of precursory gels proceeding from an aged mixture ofSn(OAmt)4 and acetylacetone at temperatures in the range200–1000 °C.N2 sorption isothermsmeasured on these SnO2 solids evidence mesoporous structures of diverse textural characteristics (i.e. pore widths of 3–50 nm and surfaceareas of 10–140 m2 g−1) in which voids virtually behave as if they are independent cylindrical pores duringcapillary condensation and evaporation.