Propane Oxidation over Pt/SrTiO₃ Nanocuboids

Abstract

Pt/SrTiO3 shows promise as a low temperature hydrocarbon combustion catalyst for automotive applications. In this study, SrTiO3 nanocuboid supports were synthesized using sol-precipitation coupled with hydrothermal synthesis, and platinum was deposited on the nanocuboids with 1, 3, and 5 cycles of atomic layer deposition (ALD). The platinum particles have a highly uniform distribution both before and after reaction testing, and range from 1 to 5 nm in size, depending upon the number of ALD cycles. These materials have a >50 °C lower light-off temperature for propane oxidation than a conventional Pt/Al2O3 catalyst, turn over frequencies up to 3 orders of magnitude higher, and show improved resistance to deactivation. The increased activity is attributed to the stabilization of a Pt/PtO core/shell structure during operating conditions by the strong epitaxy between the Pt and the SrTiO3 support.

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

“…These oxides include TiO2 [5], ZnO [6], ZnS [7], SnO2 [8], molybdates [9][10][11], and tungstates [12,13]. Among the numerous types of perovskite materials (ABO3), alkaline earth metal perovskite oxides are a veritable gold mine of diverse physical and chemical properties with large technological applications [14][15][16][17][18][19][20][21] based on ferroelectricity, piezoelectricity, non-linear optical behavior, and PL emissions, that that arise from the absence of inversion symmetry in a crystal structure [22]. ABO3 perovskite compounds have a large cation at the A-site, a smaller cation at the B-site, and the oxygen O acts as a bridging ligand, linking the Bsite cations to form a three-dimensional cage-like host framework consisting of anionic [BO3] − cages enclosed by 12 B-O-B fragments and filled by A-site guest cations.…”

Transition from Order to Configurational Disorder for Surface Reconstructions onSrTiO3(111)

“…There is currently substantial interest in the surfaces of strontium titanate for a range of applications such as thin film growth [1,2], as a model system for catalytic applications [3] or as an active catalyst with supported nanoparticles [4,5], and its use either as a substrate or an active material for oxide electronics (e.g. [6][7][8][9][10][11]).…”

“…Some details for the titanium-rich reconstructions are now understood as consisting of permutations on TiO 2 double-layers. As we point out here, these surfaces can be considered as tilings of octahedral TiO 5 [] units, where "[]" denotes a vacant oxygen site, normally in a ordered structure although glass-like disordered structures are also possible [13], in effect a Potts-type model.…”

“…3. The first has three-fold symmetry and in a partial ring of TiO 6 or TiO 5 [] units, the second contains tetrahedral units similar to the 3×3 and 4×4 structures, but now in more linear arrangements and is strictly a 1 0 1 2 structure. For completeness, the symmetry breaking is not a consequence of irregularities in the STM tip, and was locally reproducible between scans (see Supplemental Fig.…”

Scalable Production of Nanostructured Particles using Atomic Layer Deposition

“…The importance of Pt as a catalytic material has driven efforts for deposition on strontium titanate, titania, zirconia and alumina high-surface-area supports in the temperature window of 150-300°C (Christensen et al, 2009;Enterkin et al, 2011;Lobo et al, 2012;Setthapun et al, 2010;Xie et al, 2012). Moreover, the technique has also been used for the doping of Co-based Fischer-Tropsch catalysts with small amounts of Pt (0.1 wt.%) that acts as a promoter (Cronauer et al, 2011).…”