High-efficiency p–n junction oxide photoelectrodes for photoelectrochemical water splitting
Development of all oxide p–n junctions makes a significant advancement in photoelectrode catalysis functional materials. In this article, we report the preparation of TiO2 nanorod (NR)/Cu2O photoanodes via a simple hydrothermal method followed by an electrochemical deposition process. This facile synthesis route can simultaneously achieve uniform TiO2 NR/Cu2O composite nanostructures and obtain varied amounts of Cu2O by controlling the deposition time. The photocurrent density of TiO2 NR/Cu2O heterojunction photoanodes enhanced the photocatalytic activity with a photocurrent density of 5.25 mA cm−2 at 1.23 V versus RHE compared to pristine TiO2 NR photoanodes under the same conditions. It is demonstrated that the presence of Cu2O has played an important role in expanding the spectral response region and reducing the photogenerated charge recombination rate. More importantly, the results provide new insights into the performance of all oxide p–n junctions as photoanodes for PEC water splitting.