Preparation, characterization, photocatalytic activity and conductivity of BiLnZr2O7 (Ln = La, Sm, Eu and Gd)

► BiLnZr2O7 (Ln = La, Sm, Eu, Gd) were prepared by sol-gel method. ► BiLnZr2O7 (Ln = Sm, Eu) are unstable above 700 °C. ► These pyrochlores show good photoactivity in the presence of H2O2.