Accelerating surface reaction kinetics and boosting bulk as well as surface charge separation efficiency for enhanced photoelectrochemical hydrogen evolution of BaTiO3/CdS-sensitized TiO2 photoanode

A novel BaTiO 3 /CdS-sensitized TiO 2 photoanode was designed for PEC H 2 evolution. • Continuous stepped band structure was formed into TiO 2 for boosting PEC reaction. • BaTiO 3 /CdS-sensitized TiO 2 photoanode exhibits remarkably enhanced H 2 generation. • Continuous stepped charge transport channel drives charge carrier separation. • Enhanced PEC performance is due to boosted light utilization and charge separation. A key challenge for photoanodes in photoelectrochemical (PEC) water splitting hydrogen evolution is the simultaneous enhancement of light harvesting efficiency, surface water oxidation kinetics, bulk charge carrier separation and surface charge carrier injection efficiency. In this work, BaTiO 3 and CdS nanoparticles are sequentially exploited to sensitize TiO 2 photoanode, constructing continuous step-like charge transfer channels for efficient PEC hydrogen evolution. As a result, the BaTiO 3 /CdS-sensitized TiO 2 photoanode exhibits a negative shift in initial potential, a low overpotential and a reduced Tafel slope, confirming that synergistic sensitization of BaTiO 3 and CdS effectively accelerates the surface water oxidation kinetics of TiO 2 photoanode. Simultaneously, BaTiO 3 /CdS-sensitized TiO 2 photoanode achieves significantly enhanced bulk and surface charge separation efficiency, 4.2 and 2.4 times higher than those of pure TiO 2 photoanode, respectively. Consequently, the hydrogen evolution rate of constructed BaTiO 3 /CdS-sensitized TiO 2 photoanode is 37.3μmol h −1 , 11.2-fold higher than that of pure TiO 2 photoanode. The finding of this work offers a novel and reliable method for the design and construction of high performance TiO 2 -based photoanodes with continuous charge transfer channels for potential applications in PEC hydrogen production. Accelerating surface reaction kinetics and boosting bulk as well as surface charge separation efficiency for enhanced photoelectrochemical hydrogen evolution of BaTiO 3 /CdS-sensitized TiO 2 photoanode. Download: Download high-res image (172KB) Download: Download full-size image