According to a stepwise adsorption approach, TiO2 NT photoanode was co-sensitized with Eosin Y and carbon dots for photoelectrochemical water splitting. The adsorption amount of Eosin Y in co-sensitized samples increases due to the presence of carbon dots regardless of co-sensitization sequence. The absorbance of Eosin Y/carbon dots/TiO2 NT in visible light region is stronger than that of carbon dots/Eosin Y/TiO2 NT, while carbon dots/Eosin Y/TiO2 NT exhibits higher photocurrent density and hydrogen production rate. Based on the shortest electron transport time, the electron diffusion coefficient in carbon dots/Eosin Y/TiO2 NT electrode is up to 14.94 x 10(-19)cm(2)s(-1). A favorable energy levels alignment dominates in carbon dots/Eosin Y/TiO2 NT, which can further account for enhancement in charge transfer. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.