Porous Y and Cr–doped SrTiO3 materials—electrical and redox properties

Abstract

Highly porous materials in the Sr 0.96 Y 0.04 Ti 1-x Cr x O 3 system (where x = 0, 2, 4, 8 mol.%) were obtained by wet synthesis method. The structural and electrical properties of these materials were determined together with the ability to participate in oxidation/ reduction reactions, since yttrium is responsible for high electrical conductivity in reducing atmosphere and chromium is a factor affecting the catalytic properties. For the material with the highest assumed amount of chromium, the small content of an additional phase (Cr 2 O 3) was observed. SrTiO 3 lattice parameters together with the results of temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPOx) tests and Seebeck coefficient measurements allowed to determine the oxidation states of chromium in the received materials. It was shown that introduction of Y into strontium sublattice stabilises the strontium titanate structure and affects the oxidation state of chromium incorporated into the titanium sublattice. The defect structure in Sr 0.96 Y 0.04 Ti 1-x Cr x O 3 system is a complex problem, since yttrium is a donor type dopant and chromium due to the possible +3 and +6 oxidation states can be considered both acceptor and donor type one. Thus, a change in the conduction mechanism with the chromium content was observed in both oxidising and reducing atmosphere.

A comparative study on the catalytic activities of the SrTiO₃ perovskite and oxide CuO-ZnO mixed oxides for the oxidative coupling of methane

“…The results represent an O2 loss peak at over 800 o C on CuO-ZnO, and no peak was recorded for SrTiO3. This can be thought of as lattice oxygen loss (Olat), the mighty chemisorbed Oescaping from the copper cations [20]. This means that it exhibits better O lat mobility on the CuO-ZnO sample than the other catalyst.…”

The Emerging Career of Strontium Titanates in Photocatalytic Applications: A Review

“…Not only does it modify the band structure, but it also suppresses the recombination of electrons and holes. For the hydrogen generation under visible light, the most common dopants reported include Mn [41], Fe [42], Cr [43,44], Rh [45,46], Pb, Ag and Au. Saadetnejad et al doped SrTiO 3 with Au and Al for hydrogen production [47].…”

SrTiO3-SrVO3 Ceramics for Solid Oxide Fuel Cell Anodes: A Route from Oxidized Precursors

“…The perovskite-type SrTiO 3 lattice exhibits remarkable redox and dimensional stability in a wide range of T-p(O 2 ) conditions [2,16], which is essential for SOFC anode applications. Although the electrical conductivity of SrTiO 3 under reducing conditions can be improved by donor-type substitutions into one or both sublattices, it remains moderate, ≤10 S/cm under typical anode operation conditions [17][18][19][20]. Furthermore, donor-doped strontium titanates prepared under oxidizing conditions demonstrate a long relaxation of electrical conductivity due to the slow reduction kinetics at SOFC operation temperatures [21][22][23].…”