Реферат: Due to its physicochemical, optical and electric properties, tin (IV) oxide is widely used in lithium-ion batteries, gas sensors, sensitized solar cells and as a support for electrocatalysts [1]. One of the most perspective SnO2 application is to use it as a support for Pt electrocatalysts in fuel cells. Pt catalysts based on tin (IV) oxide have a higher corrosion resistance compared to that of conventional Pt catalysts based on carbon black [2]. It results in increasing durability of the electrocatalysts and thus in increasing fuel cell lifetime. In this paper, we investigate possibility of macroporous tin (IV) oxide application as a support for Pt electrocatalysts in fuel cell. Polystyrene (PS) microspheres with average diameter of ~ 250 nm were used as a hard template for the synthesis of macroporous tin dioxides. They were prepared using 4,4΄-azobis(4-cyanovaleric acid) as an initiator for styrene polymerization in accordance with the following work [3]. The first series of tin (IV) oxides was synthesized by aging of soles from tin (IV) chloride in the presence of PS microspheres suspension in water-ethanol solution. The PS was removed from SnO2 samples by annealing at 450°C in O2. The final powders were yellow. The second series of tin dioxide was synthesized from tin (II) oxalate. At first stage, tin (II) chloride was precipitated by (NH4)2C2O4 in the presence of PS suspension while stirring. Then PS was extracted from SnC2O4 by toluene. The samples of SnC2O4 were heat treated at 400°C to provide thermal decomposition. The final SnO2 powders were brown. Physicochemical characterization of SnO2 samples was carried out using low-temperature N2 adsorption (77 K), Hg porosimetry, the scanning and the transmission electron microscopies, X-Ray diffraction, X-ray photoelectron spectroscopy and CHNS analysis. The corrosion stability of SnO2 samples was studied by using accelerated “Start/Stop cycling” protocol in 1 – 1.5 V RHE of the potential range in 0.1 M HClO4 electrolyte. The curves of cyclic voltammograms were recorded in the range 0.05 - 1.2 V RHE with a sweep rate of 0.05 V/s before the "Start/Stop cycling" protocol and every 2000 cycles. Electric conductivity was studied by the impedance spectroscopy in 10-1 - 105 Hz of the frequency range at the room temperature and pressure of 1.3 MPa using home - made cell. The final tin (IV) oxide samples had a bimodal pore distribution and spherical macropores with an average diameter of 110 - 180 nm. It had been found that corrosion resistance and conductivity of the samples prepared from SnCl4 and SnC2O4 increased with increasing of the mass ratio of PS `precursor salt. It could be accounted for by particle sintering while composite calcination. At the same time, increase of sols aging time also led to the increase of corrosion resistance and conductivity. It can be resulted from increasing crystallinity of tin (IV) oxide samples. The corrosion resistance of SnO2 samples was comparable with that of commercial carbon black Vulcan XC-72.

Библиографическая ссылка: Chikunova I.O. , Semeykina V.S. , Gribov E.N. , Parkhomchuk E.V.
Synthesis and Study of Macroporous Tin (IV) Oxide as an Electrocatalyst Support
Catalysis: from Science to Industry : V International Scientific School-Conference for Young Scientists 25-29 Sep 2018