A selectively decorated Ti-FeOOH co-catalyst for a highly efficient porous hematite-based water splitting system

Abstract

We report an efficient Ti-doped FeOOH (Ti-FeOOH) co-catalyst applied on SiO_x thin layer coated Ti-doped porous Fe₂O₃ (Ti-PH) to realize an excellent water splitting photoelectrochemical cell. The SiO_x thin layer coated on Ti-doped porous hematite induces preferential deposition of the Ti-FeOOH co-catalyst on the inner pores of Ti-PH, which enhances oxygen evolution reaction performance without interrupting the absorption of light by hematite. The photocurrent density of Ti-FeOOH/Ti-PH is 4.06 mA cm⁻² at 1.23 V vs. RHE, 3.4 times higher than that of conventional worm-like hematite, with excellent long-term stability for 36 h. This represents the state-of-the-art performance among hematite-based systems with the exception of very few studies that used precious materials. Importantly, the proposed photoanode can be fabricated by a simple and cost-efficient solution-based method, i.e. with cheap precursors and without any specific equipment.