Abstract: In recent years, the increasing frequency of public health emergencies has significantly elevated antibiotic usage, resulting in environmental accumulation that threatens ecosystems and human health. Efficient and stable photoelectrocatalytic technologies are urgently needed for effective antibiotic degradation, wherein high-performance heterojunction photoanodes play a critical role. In this work, highly ordered TiO₂ nanotube arrays (TNTs) were fabricated on titanium substrates, and Cu(BDC-NH₂) MOF nanoparticles were uniformly anchored via in situ growth. By modulating precursor concentration, S-scheme heterojunction Cu(BDC-NH₂)/TNTs photoanodes with varying loadings were synthesized. The successful synthesis of the Cu(BDC-NH₂)/TNTs composite was confirmed by XRD, SEM, and XPS analyses. UV-Vis DRS, PL, and electrochemical measurements revealed that the modified photoanode exhibits a reduced bandgap (from 3.21 eV to 2.85 eV), enhanced visible absorption, reduced impedance, and a 4-fold increase in photocurrent density, indicating improved charge separation and utilization. Under visible light, Cu(BDC-NH₂)/TNTs achieved 93.36% CFZ degradation in 180 min, surpassing pristine TNTs (59.58%) and maintaining 85% efficiency after 5 cycles. The enhancement is ascribed to synergistic S-scheme charge separation and Cu(BDC-NH₂)'s adsorption capacity.