Synthesis and characterization of macroporous tin oxide coatings

Porous coatings of tin dioxide (SnO2) with a high surface area were obtained using a modified method on glass slides. The coatings were obtained with the “Doctor Blade” method and a closed drying system at room temperature. This drying system provides favorable conditions to decrease significantly cracks on the macroporous coatings. This is an alternative way to synthesize macroporous coatings using polymethylmethacrylate (PMMA) microspheres as a template. A precursor dispersion was made from the mixture of PMMA and tin tetrachloride salt dissolution at 0.5 M. The coatings synthesis parameters were optimized to obtain a uniform porous layer. The precursor dispersion and coatings were studied by thermogravimetric analysis. The coatings material surface area was 87 m2/g determined by BET, and the crystalline structure was characterized by X−ray diffraction. The structure and morphology of the coatings were determined with optical and electron microscope techniques, and the residual contaminations were studied by IR spectroscopy. The macroporous spherical diameter is around 312 ± 35 nm, and they are built by nanocrystalline size particles of 6 ± 1 nm in diameter.