Anchoring Pt on surface/bulk of LaCoO3 nanotubes via one step of coaxial electrospinning for efficient total propane oxidation

Abstract

The effect of location sites of platinum (Pt) nanoparticles on LaCoO3 support for complete catalytic oxidation of propane (C3H8) was investigated. Pt nanoparticles were anchored on the surface, bulk and surface/bulk of LaCoO3 by using three different loading methods: incipient-wetness impregnation, single-needle electrospinning and coaxial electrospinning, respectively, followed by a simple 300 °C H2 reduction process. The obtained catalysts were systematically characterized. It turns out that one step synthesis of coaxial electrospun Pt/LaCoO3 nanotubes with both surface and bulk Pt species exhibits a relatively more efficient catalytic activity, where surface Pt favors the reduction of Co3+ to Co2+ and bulk Pt accelerates that of Co2+ to Co0. Meanwhile, Co species are active sites for C3H8 oxidation despite Pt loading, but the enhanced redox property and oxygen mobility upon Pt loading are crucial for the Mars-van Krevelen mechanism obeyed total C3H8 oxidation. Additionally, good thermal stability is found over coaxial electrospun Pt/LaCoO3, removing propane at a temperature of 450 °C over 48 h without a significant decrease in propane conversion. The addition of water vapor has a little inhibition effect on the catalytic activity under the reaction condition. Such route of Pt anchoring will provide an effective means for designing highly efficient perovskite based catalysts with low precious loadings for total oxidation reaction.