Effective surface modifications on BaTiO3: linking structural motifs to methane coupling performance

Résumé fourni par la source

In this study we demonstrate that BaTiO 3 modified with 3 wt% Ca allows for the emergence of unique reduced structural motifs on the surface, which is correlated to the significant improvement of the catalytic performance of oxidative coupling of methane (OCM), particularly in the selectivity of reaction products. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and CO 2 temperature-programmed desorption (CO 2 -TPD) indicate the presence of dispersed Ca species on the surface of BaTiO 3 . Furthermore, X-ray photoelectron spectroscopy (XPS) reveals core-level shifts (CLSs) in the Ca- and Ti-XPS spectra originating from novel surface species (Ca* and Ti*) with lower core-electron binding energies. Theoretical insights from density functional theory (DFT) calculations suggest that Ca doping promotes the stability of TiO-like structural motifs on the surface. Oxygen temperature-programmed desorption (O 2 -TPD) indicates that the modified surface facilitates the generation of reactive oxygen species, which are potentially lined to methane activation. This joint experimental and theoretical approach elucidates for the first time the pivotal role of Ca in the formation of new surface motifs on BaTiO 3 , contributing to the search for new pathways for improved OCM catalysts and advancing the fundamental understanding of surface chemistry in catalytic processes.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.