Monodispersed 250 nm-sized TiO2 sphere (TiO2 SP) with large internal surface area was successfully employed in fabricating the Fe3+-grafted nitrogen-doped TiO2 (Fe3+/N-TiO2), exhibiting ultra-high visible-light photocatalytic efficiency. In evolving CO2 from the gaseous 2-propanol (IP) and acetaldehyde, the prepared Fe3+/N-TiO2 SP demonstrated twice of catalytic activity, comparing with the nanoparticle (NP)-based Fe3+/N-TiO2. Consequently, the optimized Fe3+/N-TiO2 SP exhibited 5.0-7.3 times higher efficiency than the bare N-TiO2 NP. The instability of photocatalytic activity is a well-known drawback of the Fe3+/N-TiO2 system, caused by the inherent weakness of Fe3+ ions from the chemical attacks. Herein, however, it was found that SP system with large internal surface is remarkably advantageous for protecting the grafted Fe3+ ions. With mixing of 20 wt% silica binder, which is regarded to be a typical dosage for application, photocatalytic efficiency of the Fe3+/N-TiO2 SP was decreased by only 21-25%, whereas that of the NP-based sample was reduced by 73-80%. (c) 2013 Elsevier B.V. All rights reserved.