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.