Mesoporous Yb-P-co-doped anatase-TiO2 nano-sheets were synthesized from TiCl4 hydrolysis by the hydrothermal method. The effect of Yb-P-co-doping on the surface physicochemical properties and photocatalytic activities of TiO2 and its mechanism were discussed based on the results of XRD

TEM

BET

XPS

FTIR

DRS and PL analysis. The photocatalytic activities of as-prepared samples towards the degradation of 4-chlorphenol in aqueous solution under simulated sunlight irradiation followed the order of TiO2 < Yb-TiO2 < P25 < P-TiO2 < Yb-P-TiO2

indicating the synergetic effect by Yb-P-co-doping. The TOC removal rate of 4-chlorphenol solution (20 mg·L-1) in the suspension of Yb-P-TiO2 (0.8 g·L-1) reached 87.6% after simulated sunlight irradiation for 120 min

indicating that 4-chlorphenol could be mineralized efficiently. P-doping played a crucial role on both inhibited transformation of TiO2 from anatase to rutile and improvement of surface texture properties. Yb3+ ions could capture photo-generated electrons to form Yb2+

which inturn release electrons to acceptor

such as O2 adsorbed on the surface to produce ·O2-

thus effectively inhibiting recombination of photo-generated charge carriers. The improved light absorption property of Yb-P-TiO2 was attributed to narrowing band gap owing to the cooperative effect of energy levels hybridized by the 3p orbits of P atoms and the 2p orbits of O atoms and energy levels of oxygen vaccancies. Yb-P-co-doping could further inhibit recombination of photo-generated electrons and holes

enhancing quantum efficiency

and could further increase the surface hydroxyl

which was in favor of the capture of photo-generated holes and formation of strong oxidative hydroxyl free radicals. All above factors were beneficial to enhance photocatalytic activity of Yb-P-TiO2.