<p>Pt-based noble metal catalysts hold broad application prospects, and the number of effective active sites directly influences catalytic activity. However, the diverse coordination environments surrounding noble metal sites prove difficult to unification and quantification in heterogeneous catalysis, resulting in insufficient research on effective active sites within three-way reactions. Herein, we successfully synthesized a series of atomic-level dispersion Pt/CeO₂-ZrO₂-La₂O₃-Pr₆O₁₁ (Pt/CZLP) catalysts with distinct Pt loading. Meaningfully, the activity of three-way catalytic reaction remains unchanged even if the content of the loaded Pt increases by 50% within a certain range of Pt loading (0.50%-0.75%). Various characterization tests showed that Pt particle size, dispersion, and oxygen vacancy concentration remained unchanged with increasing Pt loading. The hydrogen consumption and oxygen desorption amounts of the samples are also comparable. XPS analysis revealed a shift in the distribution of Pt oxidation states across different loadings. Quantitative analysis showed higher Pt⁴⁺ content in low-loaded Pt/CZLP catalysts. This indicates that although the Pt loading increases, the number of equivalent active sites involved in the reaction remains similar. Consequently, consistent catalytic performance was observed despite variations in Pt loading. </p> Graphical Abstract <p></p>