Abstract
In this work, we demonstrate a facile successive ionic layer adsorption and reaction process accompanied by hydrothermal method to synthesize CdS nanoparticle-modified α-Fe(2)O(3)/TiO(2) nanorod array for efficient photoelectrochemical (PEC) water oxidation. By integrating CdS/α-Fe(2)O(3)/TiO(2) ternary system, light absorption ability of the photoanode can be effectively improved with an obviously broadened optical-response to visible light region, greatly facilitates the separation of photogenerated carriers, giving rise to the enhancement of PEC water oxidation performance. Importantly, for the designed abnormal type-II heterostructure between Fe(2)O(3)/TiO(2), the conduction band position of Fe(2)O(3) is higher than that of TiO(2), the photogenerated electrons from Fe(2)O(3) will rapidly recombine with the photogenerated holes from TiO(2), thus leads to an efficient separation of photogenerated electrons from Fe(2)O(3)/holes from TiO(2) at the Fe(2)O(3)/TiO(2) interface, greatly improving the separation efficiency of photogenerated holes within Fe(2)O(3) and enhances the photogenerated electron injection efficiency in TiO(2). Working as the photoanodes of PEC water oxidation, CdS/α-Fe(2)O(3)/TiO(2) heterostucture electrode exhibits improved photocurrent density of 0.62 mA cm(- 2) at 1.23 V vs. reversible hydrogen electrode (RHE) in alkaline electrolyte, with an obviously negatively shifted onset potential of 80 mV. This work provides promising methods to enhance the PEC water oxidation performance of the TiO(2)-based heterostructure photoanodes.