Abstract: Selective oxidation of toluene into high value-added oxides is significant and challenging with O₂.An undoped g-C₃N₄ was prepared by a simple thermal exfoliation method to solve the difficulty of toluene C(sp³)-H activation, which showed excellent photocatalytic activity.The specific surface area of g-C₃N₄ was significantly increased after secondary thermal exfoliation treatment, which provides more active sites and promotes the effective separation and migration of photogenerated electron-holes.The large specific surface area is conducive to the adsorption of toluene and O₂.The optimized photocatalyst displays 86.2%total selectivity of benzaldehyde and benzoic acid, with 65.8%conversion under 400~410 nm light irradiation for 8 h at room temperature using O₂ as oxidant, while the toluene conversion rate is 2 056μmol·(g·h)^-1.