Simple preparation of nitrogen-doped TiO₂ and its performance in selective oxidation of benzyl alcohol and benzylamine under visible light

N-doped TiO , denoted as T_400, was prepared simply by the facile thermal hydrolysis of TiOSO using NH OH as both a precipitating agent and a nitrogen source. Compared to TiO without nitrogen doping, T_400 provides superior photocatalytic activity toward the selective oxidation of benzyl alcohol and benzylamine under visible light irradiation, with > 85 % conversion and > 95 % selectivity to benzaldehyde and N-benzylidenebenzylamine products, respectively. The increased photoactivity of T_400 is ascribed to enhanced visible-light absorption and efficient photogenerated charge transfer and separation as supported by UV–vis DRS, photoelectrochemical and VB-XPS results. The catalyst can tolerate the presence of substituent groups in benzyl alcohol and benzelamine molecules as > 80 % conversion and > 95 % selectivity are still achieved, which expands the scope of substrates and catalyst utilization. Band energy level of N-doped TiO compared to that of undoped TiO is determined using Mott-Schottky and UV–vis DRS measurements. Possible mechanisms for the formation of benzaldehyde and N-benzylidenebenzylamine over N-doped TiO are proposed. This work presents a simple synthesis of N-doped TiO , using a low-cost and easily handled inorganic titanium salt instead of air/moisture-sensitive alkoxide precursors and reveals its potential application toward photocatalytic synthesis of organic fine chemicals under visible light. 2 4 4 2 2 2 2 2