Improved catalytic activity under internal reforming solid oxide fuel cell over new rhodium-doped perovskite catalyst

Abstract

The catalytic partial oxidation of methane is evaluated over a Rh (2-15 mol%)-doped Sr0.92Y0.08TiO3-delta (SYT) perovskite-based catalyst prepared by the Pechini method for fuel-cell applications. The Rh dopant replaces titanium in the SYT catalyst, resulting in a catalyst with excellent and stable catalytic performance during thermal cycling in the temperature range 600-900 degrees C and in long-term stability tests at 750 degrees C for 130 h, without deactivation due to carbon coking or sintering. A systematic round-robin characterization is carried out by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and CO chemisorption to establish the chemical and physical properties of the catalyst. Adding Rh as a dopant in the catalyst significantly promotes the catalytic activity due to the presence of exsoluted rhodium particles on the catalyst surface. Small particles (2-5 nm) of Rh on the SYT surface are observed to be evenly dispersed, without agglomeration, and the turnover frequency (TOF) of the POM reaction increased. In the long-term stability tests, catalysts are tested in direct internal reforming at an SOFC anode, achieving high methane conversion (similar to 99%) in both dry and wet conditions.