Oriented generation of 1O2 from peroxymonosulfate via Co3O4 facet engineering

In this study, we synthesized Co 3 O 4 nanoparticles with distinct morphologies, including nanocube, nanotruncated octahedron, and nanopolyhedron with featured exposure of (001), (111), and (112) facets, respectively. The Co 3 O 4 -NC/CNTs-PMS (peroxymonosulfate) system demonstrated a significantly higher steady-state 1 O 2 concentration of 8.84×10⁻¹⁰ M with 99.5 % selectivity, marking a 462-fold increase compared to Co 3 O 4 -NP/CNTs-PMS. Density Functional Theory (DFT) calculations revealed that the (001) facet facilitates 1 O 2 production by lowering the energy barrier for the rate-determining step from *OH to *O. Furthermore, we introduced the sum of Hammett sigma-para constants (∑σ p ) as a predictive descriptor, capable of estimating degradation rates with 87 % accuracy. This study systematically elucidates the influence of Co 3 O 4 crystal facets on 1 O 2 generation, providing valuable insights into the design of catalysts and optimization of PMS activation strategies for the efficient degradation of recalcitrant pollutants in complex water matrices. • Co 3 O 4 with different morphologies were successfully loaded on carbon nanotubes. • Nanocube structured Co 3 O 4 exhibited best catalytic performance for PMS activation. • 1 O 2 production selectivity was tuned by Co 3 O 4 facet engineering. • DFT calculations revealed (001) facet of Co 3 O 4 showed lowest energy barrier.