<p>Graphite-phase carbon nitride (g-C₃N₄) is widely studied as a visible-light-driven photocatalyst for removing pollutants from wastewater. However, its UV-responsive phtocatalytic activation was not well characterized. In this study, precursor materials of g-C₃N₄ were screened and urea was the optimal material to synthesize g-C₃N₄. In the g-C₃N₄/UV system, reactive oxygen species (ROS), i.g., O₂^•͘−, ^•͘OH, <i>h</i>⁺ and ¹O₂ were generated. Of the ROS, O₂^•͘− was the predominate species. The degradation of rhodamine B (RhB), as a representative pollutant, was rapidly achieving the highest pseudo first-order rate constant of 5.80×10^-2 min^-1. A decrease in pH, an increase in catalyst dosage, and an enhancement of irradiation intensity could all contribute to improving the efficiency of photocatalytic degradation. Cl⁻ and Ca²⁺ did not influence the photocatalytic degradation efficiency of RhB. NO₃⁻ enhanced the photocatalytic reactions, whereas NO₂⁻, CO₃²⁻, HCO₃⁻, flavanic acid, humic acid, and citric acid all exerted inhibitory effects. The g-C₃N₄/UV system maintained a high photocatalytic degradation efficiency in five cycle tests.</p>