Room‐Temperature Synthesis of High‐Entropy Perovskite Oxide Nanoparticle Catalysts through Ultrasonication‐Based Method.

In the present study, a sonochemical‐based method for one‐pot synthesis of entropy‐stabilized perovskite oxide nanoparticle catalysts with high surface area was developed. The high‐entropy perovskite oxides were synthesized as monodispersed, spherical nanoparticles with an average crystallite size of approximately 5.9 nm. Taking advantage of the acoustic cavitation phenomenon in the ultrasonication process, BaSr(ZrHfTi)O3, BaSrBi(ZrHfTiFe)O3 and Ru/BaSrBi(ZrHfTiFe)O3 nanoparticles were crystallized as single‐phase perovskite structures through ultrasonication exposure without calcination. Notably, the entropically‐driven stability of Ru/BaSrBi(ZrHfTiFe)O3 with excellent dispersion of Ru in the perovskite phase bestowed the nanoparticles of Ru/BaSrBi(ZrHfTiFe)O3 with good catalytic activity for CO oxidation. [ABSTRACT FROM AUTHOR]