A highly efficient, defect-rich, and dimensionally engineered carbon nitride homojunction hydrogel (NTCN hydrogel) was developed for the in-situ generation of H2O2 under the illumination of visible light. The photocatalytic-self-Fenton (PSF) system was integrated with peroxymonosulfate (PMS), enhancing the production of reactive oxygen species, which aided the tetracycline degradation to 99.5 % in 8 min. The NTCN hydrogels also displayed a maximal reusability of 20 cycles with a slight decline in the degradation efficiency. The superior catalytic performance is indicated by the establishment of a Z-scheme junction in the NTCN hydrogel, which is attributed to the higher separation efficiency, rapid H2O2 generation, and synergistic interaction between the PMS and PSF in the hybrid oxidation system. The mechanistic pathways revealed the synergistic interaction between the PMS and H2O2 in the PSF-PMS hybrid oxidation system, enhancing the performance of NTCN hydrogels in a wider range of pH. Under basic pH conditions, the PMS and H2O2 are produced on the surface of NTCN hydrogels to mutually generate [rad]OH and 1O2, which led to enhance the lower degradation efficacy in the PSF system. At acidic pH, the O2[rad]− emerges as a predominant Reactive Oxygen Species (ROS), and the synergistic action of H2O2 and PMS completely avoided the dependency on protons by the PSF-PMS system. This study describes a highly efficient and sustainable hybrid multifunctional oxidation system for the purification of tetracycline from synthetic wastewater.