Pure and Gd3+-doped TiO2 nano-particle with different amounts of Gd3+-doping were prepared by the acid-catalyzed sol-gel method using Ti(OC4H9)4 and Gd(NO3)3 as precursors and characterized with XRD

BET

XPS and SPS.The effects of the amount of Gd3+-doping and calcination temperature on the photocatalytic activity for photocatalytic degradation of methylene blue (MB) in aqueous solution

phase structure

crystallite size

surface texture properties of the nanopowders were investigated

and the mechanism of the effects of Gd3+-doping on the photocatalytic activity of TiO2 nano-particles was also discussed in combination with the surface photoelectric properties and surface composition of the nano-particle.The results indicated that Gd3+-doping could enhance the photocatalytic activity of TiO2 nano-powder as compared with pure TiO2.0.5% (mass) Gd3+-doped TiO2 nano-powder calcined at 500℃ for 2 h show the highest photocatalytic activity.The presence of Gd3+ in TiO2 could inhibit the phase transformation from anatase to rutile

restrain crystal grain growth

and enhance the threshold value of photoresponse

which resulted in increase in the photoactivity.XPS result showed that Gd3+-doping can lead to decrease in the density of surface hydroxyl groups.