This paper describes a general aqueous sol–gel route for the synthesis of a series of rare earth stannates, Ln₂Sn₂O₇ (Ln = Y, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Lu), with pure pyrochlore phase via the assistance of a cetyltrimethyl ammonium bromide (CTAB) surfactant. The route involves first the formation of CTAB-inorganic lamellar structures and then their thermal decomposition at 800 °C to yield the pyrochlore Ln₂Sn₂O₇ nanocrystals. Techniques using a thermo-gravimetric/differential thermal analyzer (TG-DTA), x-ray diffraction (XRD) and transmission electron microscopy (TEM) as well as selected-area electron diffraction (SAED) have been employed to characterize the as-synthesized Ln₂Sn₂O₇ nanocrystals. Furthermore, photoluminescence (PL) of the 5% Eu³⁺ activated Ln₂Sn₂O₇ nanocrystals and carbon monoxide catalytic oxidation over the as-obtained Ln₂Sn₂O₇ nanocrystals were investigated. The results indicate that the PL properties as well as the catalytic activity changes significantly with the ionic radii of the rare earth elements.