Rare earth oxide-doped titania nanocomposites with enhanced photocatalytic activity towards the degradation of partially hydrolysis polyacrylamide

Rare-earth oxide-doped titania nanocomposites (RE3+/TiO2, where RE = Eu3+, Pr3+, Gd3+, Nd3+, and Y3+) were prepared by a one-step sol–gel-solvothermal method. The products exhibited anatase phase structure, mesoporosity, and interesting surface compositions with three oxygen species and two titanium species. The products were used as the photocatalysts to degrade a partially hydrolysis polyacrylamide (HPAM) under UV-light irradiation, a very useful polymer in oil recovery. For comparison, Degussa P25 and as-prepared pure TiO2 were also tested under the same conditions. The enhanced photocatalytic activity was obtained on as-prepared Eu3+ (Gd3+, Pr3+)/TiO2 composites, and the reasons were explained. Finally, the degradation pathway of HPAM over the RE3+/TiO2 composite was put forward based on the intermediates produced during the photocatalysis procedure.