Dual Modification Strategy: Passivation Layer and Cocatalyst on Hematite for Improved Photoelectrochemical Water Oxidation
Zhi Yin, Xueyang Leng, Dutong Wang, Lingling Xu
Abstract
α-Fe 2 O 3 is a very attractive photoanode for photoelectrochemical (PEC) water decomposition. However, its short diffusion length, poor conductivity, and fast charge-carrier recombination severely limit device efficiency. Here, coloading an Al 2 O 3 passivation layer and a CoO x cocatalyst onto Ti-doped α-Fe 2 O 3 was carried out to promote PEC water oxidation by improving charge separation and transfer at the electrode/electrolyte interface and inhibiting photocarrier recombination. The optimized Ti:Fe 2 O 3 /Al 2 O 3 /CoO x photoanode shows a large photocurrent density of 1.41 mA cm –2 at 1.23 V vs reversible hydrogen electrode, which is 47 times greater than that of a pristine Ti:Fe 2 O 3 photoanode. The dual modifications with a combined passivation layer and cocatalyst on the photoanode verify a valuable way for solar energy conversion in PEC water oxidation.