Fabrication of Hematite Photoanode Consisting of (110)‐Oriented Single Crystals

Abstract

AbstractIn this work, α‐Fe2O3 photoanode consisted of (110)‐oriented α‐Fe2O3 single crystals were synthesized by a facile hydrothermal method. By using particular additive (C4MimBF4) and regulation of hydrothermal reaction time, the Fe‐25 consisted of a single‐layer of highly crystalline (110)‐oriented crystals with fewer grain boundaries, which was vertically grown on the substrate. As a result, the charge separation efficiency and photoelectrochemical (PEC) performance of Fe‐25A (Fe‐25 after dehydration treatment) have been greatly improved. Fe‐25A yields a photocurrent of 1.34 mA cm−2 (1.23 V vs RHE) and an incident photon‐to‐current conversion efficiency (IPCE) of 31.95 % (380 nm). With the assistance of cobalt–phosphate water oxidation catalyst (Co−Pi), the PEC performance could be further improved by enhancing the holes transfer at electrode/electrolyte interface and inhibiting surface recombination. Fe‐25A/Co−Pi yields a photocurrent of 2.67 mA cm−2 (1.23 V vs RHE) and IPCE value of 50.8 % (380 nm), which is 3.67 times and 2.39 times as that of Fe‐2A/Co−Pi. Our work provides a simple method to fabricate highly efficient Fe2O3 photoanodes consist of characteristic (110)‐oriented single crystals with high crystallinity and high quality interface contact to enhance charge separation efficiencies.