Revealing the interplay between intelligent behavior and surface reconstruction of non-precious metal doped SrTiO3 catalysts during methane combustion?

The impact of surface reconstruction of a model perovskite, SrTiO3 (STO), on CH4 activation for combustion and oxidative coupling was previously revealed that the reaction rate was proportional to the creation of Srterminated step sites. Doped perovskites (SrTi1_xMxO3, M=metal dopant) present yet another form of reconstruction throughout the surface and the bulk, where the metal dopant can migrate in and out of the perovskite lattice, also known as intelligent behavior. In this work, understanding the interplay between perovskite surface reconstruction (surface termination) and the intelligent behavior is tackled for the first time, and the catalytic consequences are probed with CH4 combustion as a model reaction. A set of experimental techniques, including XRD, Raman spectroscopy, X-ray adsorption spectroscopy, kinetic measurements, as well as DFT calculations were used to understand the catalytic behavior of the reconstructed surfaces of Ni and Cu-doped STO for methane combustion. We found that during methane oxidation, the diffusion of Ni and Cu into the lattice due to the intelligent behavior is accompanied by Sr enrichment on the surface of the perovskite. This Srenrichment process is reversible when Cu or Ni species exsolute as clusters/nanoparticles upon H2 treatment. Such a surface reconstruction is found to greatly impact the catalytic activity of doped perovskites towards methane combustion.

Automated summary

This study explores the interplay between surface reconstruction (surface termination) and intelligent behavior and investigates the catalytic consequences through CH4 combustion as a model reaction. The results reveal that during methane oxidation, intelligent behavior leads to the diffusion of Ni and Cu into the perovskite lattice, resulting in Sr enrichment on the surface. This Sr enrichment process is reversible when Cu or Ni species exsolute as clusters/nanoparticles upon H2 treatment. Surface reconstruction greatly impacts the catalytic activity of doped perovskites towards methane combustion.