Enhanced oxidative coupling of methane using strontium and barium doped lanthanum or samarium oxide nanocatalysts

In this study, nanoparticle-based La2O3 and Sm2O3 catalysts with varying amounts of Sr or Ba doping were synthesized and evaluated for their performance in the oxidative coupling of methane (OCM). The catalysts were characterized using a range of techniques, including XRD, BET surface area analysis, NH3-TPD, CO2-TPD, XPS and SEM. The results indicated that strontium diffuses more effectively into the metal oxide lattice than barium, resulting in a greater increase in surface basicity and a corresponding positive impact on the catalytic performance. The Sr-doped La2O3 catalysts, in particular those containing 8 wt% Sr, exhibited an enhanced C-2 hydrocarbon yield, reaching a maximum of 14.3% at 510 degrees C. In contrast, Ba demonstrated a minimal contribution due to its stable carbonate formation and limited diffusion into the catalyst structure. While higher surface areas were generally associated with reduced catalytic performance, increased surface basicity proved beneficial for enhancing reaction efficiency. The 8 wt% Sr/La2O3 catalyst exhibited stability over 50 h, suggesting potential for long-term catalytic applications in industrial methane conversion.