A simple strategy to greatly increase the thermal stability of nanocrystalline anatase has been put forward to fabricate efficient TiO2-based photocatalysts under ultraviolet irradiation, via the surface modification with phosphate anions. The results show that the increased anatase thermal stability is attributed to the roles of the phosphate modification effectively inhibiting the contacts among anatase nanocrystals. Compared to un-modified TiO2, the modified TiO2 calcined at high temperature (over 700 degrees C) exhibits much high photocatalytic activity for degrading Rhodamine B (or phenol) solution, even superior to the commercial P25 TiO2. The activity enhancement is mainly attributed to the increased separation rate of photogenerated charge carriers on the basis of the measurements of steady state-and transient state-surface photovoltage spectroscopy. This work would provide a practical route to reasonably design and synthesize high-performance TiO2-based nanostructured photocatalysts with high anatase thermal stability. (C) 2011 Elsevier B. V. All rights reserved.