Three Birds, One‐Stone Strategy for Hybrid Microwave Synthesis of Ta and Sn Codoped Fe2O3@FeTaO4 Nanorods for Photo‐Electrochemical Water Oxidation

Abstract

AbstractA “three birds, one stone” strategy is proposed to enhance the performance of hematite photoanode for photoelectrochemical water splitting. One‐pot hybrid microwave synthesis of Ta and Sn codoped Fe2O3@FeTaO4 core–shell nanorods on F:SnO2 substrate achieves three synergetic effects simultaneously: i) core–shell heterojunction formation to alleviate the significant electron–hole recombination; ii) preserved morphology of small‐diameter nanorods to provide a short hole diffusion distance; and iii) Ta and Sn codoping to enhance the electrical conductivity. These effects are not possible with conventional high temperature thermal synthesis in a furnace. As a result, core–shell Fe2O3@FeTaO4 electrode with FeOOH cocatalyst achieves a photocurrent density of 2.86 mA cm−2 at 1.23 VRHE under AM 1.5 G simulated sunlight (100 mW cm−2), which is ≈2.4 times higher than that of bare hematite (1.17 mA cm−2). In addition, the FeOOH/Fe2O3@FeTaO4 electrode exhibits a high surface charge separation efficiency of ≈85% and a modest bulk charge separation efficiency of ≈24%.