Carbon nanotube as a nanoreactor for efficient degradation of 3-aminophenol over CoOx/CNT catalyst

Nanoreactors have been enlightened by enzymes to benefit from particular confinement for purpose of the acceleration of catalytic reactions and rendering them specific. Herein, we have first designed and synthesized the high-efficiency carbon nanotube-stabilized cobalt oxides nanoparticles (CoO x /CNT), via immobilization of CoO x nanoparticles onto carbon nanotube (CNT), for 3-aminophenol (3-AP) degradation via peroxymonosulfate (PMS) activation. Among them, carbon nanotube is used as a nanoreactor for efficient degradation of 3-AP over CoO x /CNT nanocomposite . The detailed physical characterizations illustrate that CoO x /CNT presented a nanotube-shaped structure, and some CoO x nanoparticles were encapsulated into CNT, and the molar ration of Co and O in CoO x was calculated to be 1:1.006, where CoO 1.006 might be the mixture of CoO and Co 3 O 4 . The comparison with other carriers (including MoS 2 , CeO 2 , ZnO and ZrO 2 ), CoO x /CNT provides the highest 3-AP degradation efficiency, highlighting the key role of CNT, as a nanoreactor, in CoO x /CNT for activating PMS to degrade 3-AP. The super-high catalytic activity of CoO x /CNT nanocomposite in the 3-AP degradation is owing to the specific confinement (encapsulation of some CoO x by carbon nanotubes). It seems the electron transfer from CNT to Co atom surface, enriched its surface electron cloud density, which is favorable for PMS activation. Quenching experiments and electron paramagnetic resonance (EPR) result have verified that SO 4 • - and OH• are the primary reactive oxygen species in 3-AP degradation over CoO x /CNT/PMS system. This study provides a new research orientation for the synthesis of efficient and stable carbon nanotube-encapsulated Co-based nanocatalyst for wastewater treatment .