In this study, palladium-loaded graphitic carbon nitride nanoparticles (Pd@g-C₃N₄) were synthesized and subsequently immobilized onto a titanium metal surface via the electrophoretic method to develop a novel, stable, and efficient catalyst for photoelectrocatalytic processes under visible light irradiation. In the first step, the parameters affecting the immobilization process—including suspension concentration, applied voltage, and deposition time—were investigated and optimized to achieve maximum stability of the catalytic layer. The structural and surface characteristics of the prepared catalyst were identified using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and UV-Visible Diffuse Reflectance Spectroscopy (UV–Vis DRS). The DRS analysis results showed that the energy bandgap decreased from approximately 2.85 eV for pure g-C₃N₄ to about 2.56 eV in the palladium-loaded sample, indicating improved visible light absorption and a subsequent increase in photoelectrocatalytic activity. In this study, the effects of operational variables, including solution pH, applied voltage, electrolyte concentration, and reaction time, on the removal efficiency of tetracycline were investigated. The results demonstrated that under optimized conditions—specifically at pH 8, an applied voltage of 0.9 V, an electrolyte concentration of 0.3 g of Na₂SO₄, and under visible light irradiation from a 400 W high-pressure mercury lamp—the maximum degradation efficiency of tetracycline reached 94%. These findings highlight the significant photoelectrocatalytic efficiency of the Pd-loaded g-C₃N₄ nanocomposite immobilized on a titanium substrate for the removal of persistent pharmaceutical pollutants in aqueous media under visible light irradiation.