Nitrogen-Doped Carbon Nanolayer Coated Hematite Nanorods for Efficient Photoelectrocatalytic Water Oxidation

To improve the charge carrier transfer ability in the bulk and at the surface of α-Fe2O3 and accelerate the water oxidation kinetics at the photoanode/electrolyte interface, herein, starting with Ti-doped α-Fe2O3 nanorods, a nitrogen (N) doped carbon (C) nanolayer was coated on the surface of nanorods through a facile hydrothermal method, following a thermal treatment in Ar atmosphere. It was revealed that the N-doped C nanolayer, acting as the passivation layer and/or the water oxidation catalyst, could efficiently extract and collect photoexcited holes from the bulk of α-Fe2O3 and then inject them into the electrolyte for the accelerated water oxidation reaction, by inhibiting both the bulk and surface charge carrier recombination. As a result, the photocurrent density of Ti-doped α-Fe2O3 nanorods coated with N doped C nanolayer was increased by ∼2.7 folds at 1.8 V vs. RHE, as compared with the pristine one.