Cation deficiency tuned LaCoO3−δ perovskite for peroxymonosulfate activation towards bisphenol A degradation

Perovskite-based materials have been demonstrated to be effective for peroxymonosulfate (PMS) activation towards wastewater treatment. However, the effect of cation deficiency in perovskite oxides has not been well illustrated. In this study, cation deficient LaCoO3−δ perovskite oxides have been prepared to tune the catalytic activity. B-site cation deficiency on the LaCoO3−δ perovskite oxides promotes the catalytic performance while A-site cation deficiency is detrimental to the catalysis for PMS activation. The first-order kinetic rate of B-site cation deficient LaCoO3−δ perovskites prepared via sol-gel method is 0.591 min−1, higher than that of LaCoO3−δ perovskites with A-site cation deficiency (0.118 min−1) and no cation deficiency (0.243 min−1). About 90% of organics could be mineralized completely through the catalysis of B-site cation deficient LaCoO3−δ perovskites in 60 min. The sulfate radicals and singlet oxygen are responsible for the catalytic degradation of bisphenol A. The surface Co(II) site, surface hydroxyl group and oxygen vacancies on the LaCoO3−δ perovskite oxides are the active sites for catalysis. The excellent catalytic activity induced by B-site cation deficiency can be attributed to the high charge transfer and surface reaction rate, abundant Co(II) site, surface hydroxyl group and oxygen vacancies.