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This study proposed a new facile route to rational creating oxygen-vacancy (Vo)-rich surface of Co3O4 nanosheets by acetic acid leaching. The acid leached Co3O4 nanosheets was very active in peroxymonosulfate (PMS) activation for degradation of atrazine (ATZ), 99.4% ATZ removal efficiency was achieved in Co3O4-a/PMS system within only 30 min with the reaction rate constant (k) = 0.17 min−1, which was much superior to that of commercial Co3O4 nanopowder (k = 0.01 min−1) and pristine Co3O4 nanosheets (k = 0.04 min−1). Radical quenching experiments and electron spin response (ESR) tests revealed the superoxide radical (O2.−) and singlet oxygen (1O2) were the domain reactive oxygen radicals in the ATZ degradation process. This study provides a promising route to design Vo-rich metal oxides to activate PMS for refractory organic contaminants degradation. [ABSTRACT FROM AUTHOR]

Clarifying the facet‐dependent activity of Co3O4 towards C3H8 combustion is of great importance to have a deep understanding of reaction mechanism and develop highly active Co3O4 based catalysts for light hydrocarbon combustion. In this work, four different Co3O4 nanocatalysts which dominantly exposed {100}, {111}, {110} and {112} facets, respectively, were synthesized via hydrothermal method and further tested in C3H8 combustion. The catalytic activity of different crystal planes varied as the order of {111}>{100}>{110}>{112}. The Co3O4 catalyst with {111} facets exhibited the best catalytic performance with T50 and T90 as low as 209 and 239 °C, respectively. DRIFT and DFT calculations revealed that the facile activation of C−H bond on Co3O4 {111} planes is responsible for the high activity. Moreover, the higher activity of lattice oxygens and easy activation of gas phase oxygen could also contribute to the excellent catalytic performance. [ABSTRACT FROM AUTHOR]