Cobalt Oxides Anchored Ti₃AlC₂ MXene for Efficient Removal of Antibiotic Ornidazole in Water

Abstract This paper presents a novel method for synthesizing CoO x /Ti 3 AlC 2 composite catalysts using MAX‐phase Ti 3 AlC 2 without etching the Al layer. By employing simple alkali precipitation and high‐temperature calcination, the resulting CoO x /Ti 3 AlC 2 catalyst demonstrated superior performance in the peroxymonosulfate (PMS) degradation of ornidazole (ONZ) compared with CoO x /Ti 3 C 2 (MXene). The CoO x /Ti 3 AlC 2 ‐0.05+PMS catalyst achieved complete ONZ degradation (30 mg L −1 ) within 30 min, significantly outperforming CoO x /MXene‐0.05+PMS, which only achieved 91% removal. The degradation rate constant (Kobs) for CoO x /Ti 3 AlC 2 ‐0.05+PMS (0.19325 min −1 ) is nearly twice that of CoO x /MXene‐0.05+PMS (0.08412 min −1 ), highlighting the crucial role of the Al layer in catalyst activation. Characterization revealed a uniform CoO x nanoparticle dispersion on Ti 3 AlC 2 , and the CoO x /MXene‐0.05 system demonstrated high stability and adaptability in natural water with minimal Co ion leaching. Additionally, radical scavenging and electron paramagnetic resonance (EPR) spectroscopy elucidated the reactive oxygen species (ROS) generation mechanisms and identified 11 ONZ degradation intermediates, suggesting potential degradation pathways. This approach eliminated Al etching and offered a cost‐effective and environmentally friendly method for catalyst synthesis.