Flame Reduced TiO2 Nanorod Arrays with Ag Nanoparticle Decoration for Efficient Solar Water Splitting

Low photogenerated charge density and fast surface charge recombination of TiO 2 are two critical factors hampering its solar-to-hydrogen conversion for photoelectrochemical water splitting. Herein, we demonstrate an efficient and facile flame reduction method to produce rich oxygen vacancies in single-crystal rutile TiO 2 nanorod arrays without destroying the catalyst and conductive substrate at ambient conditions. The oxygen vacancies improve the conductivity of TiO 2 and act as the role that intermediate electron donor increases the charge density. We further construct a Schottky junction by depositing Ag nanoparticles on the flame reduced TiO 2 to enhance surface charge separation efficiency. The optimal TiO 2 photoelectrodes exhibit an astonishing surface charge separation efficiency of 91% as well as photocurrent density as high as 1.52 mA cm –2 (at 1.23 V, vs reversible hydrogen electrode), which is ∼7.2 times that of the pristine rutile TiO 2 (0.21 mA cm –2 ). This work demonstrates that the facile flame reduction method combined with Schottky junction construction exhibits significant application prospects for the enhanced solar conversion efficiency of metal oxide photoelectrodes.