Loading the FeNiOOH cocatalyst on Pt-modified hematite nanostructures for efficient solar water oxidation

Abstract

A FeNiOOH-decorated hematite photoanode has been prepared using a facile electrodeposition method, with a significant cathodic shift of the onset potential (up to 190 mV) compared to the pristine sample. Synchrotron radiation based techniques have been used to identify the composition of the catalyst indicating the presence of FeOOH and NiOOH (FeNiOOH). The enhanced performance can be attributed to the better oxidation evolution reaction kinetics with the FeNiOOH cocatalyst. The FeNiOOH-decorated hematite is very stable for a long time. Moreover, the cocatalyst can be well coupled to the Pt-modified hematite photoanode achieving a high photocurrent of 2.21 mA cm⁻² at 1.23 V vs. RHE. The good catalytic properties and the facile preparation method suggest that the decoration of FeNiOOH is a favorable strategy to improve the performance of hematite.