Amorphous Ta2OxNy-enwrapped TiO2 rutile nanorods for enhanced solar photoelectrochemical water splitting

Abstract

This work demonstrated the 12 fold-enhanced solar water splitting over the type-II core-shell nanostructured TiO2 rutile photoanodes by orienting the charge flow and accelerating the hole transport to water-oxidation sites. Such nanoheterostructured photoanodes were designed rationally and prepared by a facile strategy to enwrapping an amorphous Ta2OxNy layer on surface of TiO2 nanorods grown on the FTO glass substrates, consequently the incident photon-to-current conversion efficiency was increased from 2.2% to 22.6% in a two-electrode system under 390 nm light irradiation. The activity results showed that under AM 1.5 G illumination, the photocurrent output of TiO2@Ta2OxNy photoanodes reached a stable density of 1.32 mA cm−2 at 1.23 V vs RHE, and which is 12 times and ca. 4.3 times than that of the pristine TiO2 and TiO2@Ta2O5 counterparts, respectively. Correspondingly, the oxygen evolution rate was improved from 20.3 to 112.7 mmol m−2 h−1. A solar-to-chemical energy conversion efficiency of ca. 1.49% was achieved at 1.23 V vs RHE.