The redox-driven hydrolysis precipitation is developed to atomically disperse Pt on TiO₂ by involving high-valence Mn cations as the “anchor” into TiO₂. With multiple characterizations including Cs-HAADF-STEM and XAFS, single-atom state of Pt on the surface of support is evidenced. Due to high dispersion of Pt and strong interaction between Pt and MnO_x-TiO₂ (Mn-TiO₂), the physicochemical properties of catalysts are obviously improved. With combination of theoretical calculation and characterization, it is revealed that metallic Pt atom is stabilized by lattice oxygen of support. As observed, only 0.5% nominal amount of Pt loading (actual amount = 0.47%) on Mn-TiO₂ support can meet the demands of complete removal of HCHO with high/low concentrations and severe space velocity at low temperature. Through analysis of in-situ DRIFTS of HCHO, the catalytic oxidation of HCHO over Pt/Mn-TiO₂ obeys Mars-van-Krevelen mechanism. By associating with H-D exchange, it is found that introduction of water vapor can inhibit side-reactions and facilitate deep oxidation of HCHO.