Perfluorooctanoic acid (PFOA) is an emerging persistent organic pollutant and receives increasing concerns due to its global occurrence and resistance to most conventional decomposition methods. In2O3 nanoporous nanospheres (NPNSs) with uniform size (similar to 100 nm) were obtained by calcining nanoporous InOOO/In(OH)(3) nanospheres and its photocatalytic activity for PFOA decomposition were evaluated. The InOOH/In(OH)(3) precursor was self-assembled from ultrathin nanoplates (similar to 2 nm) in an ethylenediamine-assisted alcohol-thermal system. The In2O3 NPNSs possessed a high value of specific surface area (39.0 m(2) g(-1)) and a large number of nanopores (similar to 6 nm). Compared with commercial In2O3 nanocrystals (NCs) and TiO2 (Degussa P25), In2O3 NPNSs showed a remarkable photocatalytic activity to decompose PFOA with the half-life of 7.1 min. The first-order rate constant of PFOA by In2O3 NPNSs was nearly 9 and 54.6 times higher than that by In2O3 NCs and TiO2 respectively. The superior activity of In(2)O3 NPNSs for PFOA decomposition can be attributed to its nanoporous structure, large specific surface area, and direct reaction between the photogenerated hole and PFOA. (C) 2012 Elsevier B.V. All rights reserved.