Inducing intrinsic oxygen vacancies (VO) through structural engineering, rather than relying on complex doping or heterostructure

formation, represents a novel and simplified strategy in developing high-efficiency catalyst. In this work, we 

report a facile and scalable chemical precipitation route to synthesize copper (II) oxide (CuO) nanorods (NRs) characterized

by an unprecedented density of VO defects. These NRs serve as an extraordinary activator for peroxymonosulfate 

(PMS) in a sulfate (SO•−

4 ) radical-based advanced oxidation process (AOP). The CuO-PMS synergy achieved significant 

degradation of 10 ppm of 4-nitrophenol (4NP), reaching 84.47% degradation and 88.11% total organic carbon (TOC) 

mineralization within 5 min. With only small doses of 0.1 g/L CuO and 0.65 mM PMS, the system further achieved 

95.36% degradation and 91.39% mineralization of the same sample. This high performance is attributed to the synergy of 

lower crystallinity, higher surface area, and greater VO defects presence in the NRs compared to bulk CuO. The system 

operated effectively under normal to low-alkaline pH conditions, exhibiting a high capacity to oxidize higher 4NP doses, 

demonstrating excellent reusability, and a wide applicability range for various pollutants. Singlet oxygen (1O2) has been 

identified as the main driver of the oxidation process, as confirmed by scavenger tests. This study provides a pivotal blueprint

for the design of defect-rich binary metal oxides, offering a pragmatic yet powerful solution for high-performance 

wastewater remediation.