Highly monodisperse and crystalline anatase phase TiO2 nanospheres have been synthesized at room temperature from organometallic precursor, titanocene dichloride and sodium azide. The photoelectrochemical (PEC) water splitting performance on the TiO2 nanospheres was studied under illumination of AM 1.5G. The optimized photocurrent density and photoconversion efficiency of TiO2 NSPs were observed similar to 0.95mAcm(-2) at 1.23V and 0.69%, respectively. The transient photocurrent response measurements on the TiO2 NSPs during repeated ON/OFF visible light illumination cycles at 1.23V vs RHE show that both samples exhibited fast and reproducible photocurrent responses. The TiO2 NSPs show excellent catalytic stability, and significant dark current was not observed even at high potentials (2.0V vs RHE). Copyright (c) 2015 John Wiley & Sons, Ltd.