Characteristics of Sr1-xYxTi1-yRuyO3+/ - delta and Ru-impregnated Sr1-xYxTiO3+/ - delta perovskite catalysts as SOFC anode for methane dry reforming

Abstract

Dry reforming, a technique to combine methane and carbon dioxide, has received significant attention in efforts to produce synthesis gas (carbon monoxide and hydrogen). These gases can subsequently be used for Cl chemistry applications, and even for high-temperature fuel cell devices. However, suitable electrode materials with highly active and stable properties remain to be found for efficient utilization of a Cl fuel-based fuel cell system. A promising electrode material of yttria-doped strontium titanium oxide with trace ruthenium (Sr0.92Y0.08Ti0.98Ru0.02O3+/-delta; SYTRu) was developed in this work for an efficient and stable dry-reforming catalyst and compared to a Ru-loaded SYT (Ru/SYT) catalyst. The substituted Ru in the former sample was uniformly incorporated (primarily in the atomic level) in the SYT lattice with a perovskite structure. Different Ru species were observed in this case, unlike in the Ru/SYT sample. Ru doping decreased the oxygen vacancy formation energy in calculated by density functional theory and led to a high activity for the surface oxygen. The surface oxygen donating ability to the catalyst was responsible for facilitating the dissociation and decomposition of CH4 and CO2. This led to high conversion efficiency, good syngas selectivity, and stability, along with a small amount of coke formation.