Enhancing the Photoelectrochemical Performance of a Hematite Dendrite/Graphitic Carbon Nitride Nanocomposite through Surface Modification with CoFeOx

In this article, we report the surface modification of a hematite dendrite/graphitic carbon nitride composite (HD/g-CN) with an oxygen evolution catalyst (OER), specifically CoFeOx, to achieve enhanced photoelectrochemical (PEC) water splitting under visible-light irradiation. Such modified hematite dendrites are studied for the first time for PEC water splitting and demonstrate higher activity compared to unmodified composites. The synthesized composites are characterized by X-ray diffraction spectroscopy, Raman spectroscopy, field emission scanning electron microscopy (FESEM) and elemental dispersive analysis (EDX). The photoelectrochemical performance was studied by linear sweep voltammetry (LSV) under visible-light irradiation. The photoelectrochemical characterization reveals that the CoFeOx/HD/g-CN composite shows a maximum photocurrent density of 0.60 mAcm(-2) at 1.23 V versus RHE (reversible hydrogen electrode), which is comparable to the best reported value of hematite. A Mott-Schottky analysis demonstrates the formation of a p-n heterojunction of CoFeOx with the HD/g-CN composite which is responsible for the enhanced PEC activity as a result of efficient separation of photogenerated electronhole pairs.