A Three-Dimensional Branched TiO<sub>2</sub> Photoanode with an Ultrathin Al<sub>2</sub>O<sub>3</sub> Passivation Layer and a NiOOH Cocatalyst toward Photoelectrochemical Water Oxidation
Changhai Liu, Chao Zhang, Ge Yin, Tingting Zhang, Wenchang Wang, Guofu Ou, Haozhe Jin, Zhidong Chen
Abstract
Photoelectrochemical (PEC) water splitting provides an alternative strategy for clean and renewable hydrogen production; however, the practical application is severely limited by the low solar conversion. Herein, a novel and simple strategy has been developed to construct a 3D branched TiO2 photoanode with an ultrathin Al2O3 passivation layer and NiOOH cocatalyst. The structure and properties of the as-obtained photoanodes are explored by X-ray diffraction, Mott–Schottky, electrochemical impedance spectroscopy, and open circuit voltage measurements. The as-obtained B-TiO2/Al2O3/NiOOH ternary heterojunction with a high-quality contact interface exhibits improved light absorption ability, an enhanced photocurrent density of 1.42 mA/cm2 at 1.23 VRHE, high conversion efficiency (0.44% at 0.80 VRHE), and excellent stability compared to pristine TiO2 and alone-Al2O3 or NiOOH decorated TiO2 photoanodes. Therefore, this work could offer a new approach to designing and fabricating high-quality contact interfaces between photoelectrodes and various cocatalysts.