Pure monoclinic BiVO4, La-doped BiVO4 catalysts, and MCM-41 samples containing BiVO4 and La-doped BiVO4 were prepared via precipitation. An improved photocatalytic activity was observed in the degradation of 2,4,6-trichlorophenol using La-doped samples. With higher amounts of La, a partial tetragonal crystalline phase of bismuth vanadate was found. The pure and La-doped BiVO4 sample were loaded onto the mesoporous silica MCM-41. Enhanced catalytic activity was achieved in comparison with those not being loaded onto MCM-41. The lowered band gap following the introduction of La ions and also formation of higher amounts of surface complexes with pollutant molecules are the main reasons of the improved catalytic activity. A comparison of the extent of different chlorophenols toward degradation over the prepared catalysts revealed that under current experimental conditions the samples with more chloride groups suffer higher degradation.