In-situ synthesis of highly dispersed Cu-CuxO nanoparticles on porous carbon for the enhanced persulfate activation for phenol degradation

Abstract Copper-mediated activation of persulfate (PS) has been widely investigated for the degradation of refractory organic pollutants. However, the dispersion of the active copper sites in the catalysts remains a great challenge. Herein, a series of well-dispersed Cu-CuxO embedded into carbon matrix composites (Cu-CuxO@C) were fabricated via the pyrolysis of HKUST-1 precursor. The Cu-CuxO@C catalysts were fully characterized by SEM, HRTEM, XRD, BET, Raman, FT-IR, and XPS. The results show that the Cu-CuxO@C calcinated at 700 °C (Cu-CuxO@C-700) contained multivalent Cu components. Their heterogeneous activation of PS for phenol degradation was also investigated. Cu-CuxO@C-700 removed completely phenol with a kobs value greater than 0.40 min−1. Such superior catalytic activity is mainly attributed to the synergistic effect of carbon matrix adsorption and multivalent Cu active site electron transfer. The reusability studies reveal that the performance of the used Cu-CuxO@C-700 could be reactivated through re-calcination. Moreover, quenching tests and EPR analyses revealed that OH and SO4 − are involved in phenol degradation. The electron transfer process and resistance of Cu-CuxO@C-700 were described by electrochemical method. Finally, the catalytic mechanism was explored by XPS, FT-IR and Raman analyses. This study provides new insights into the fabrication of heterogeneous catalysts for sulfate radical activiation.