A Photoresponsive Rutile TiO2 Heterojunction with Enhanced Electron–Hole Separation for High‐Performance Hydrogen Evolution

Abstract Rutile titanium dioxide (TiO 2 ) is a promising photocatalyst due to its high thermodynamic stability and few intragrain defects. However, it has not yet achieved photocatalytic activity comparable to that of anatase TiO 2 owing to its higher recombination rate of electron–hole pairs. To effectively separate the electron–hole pairs in rutile TiO 2 , a facet heterojunction (FH) structure to prolong the lifetime of the photogenerated electrons is proposed. Ultrathin TiO 2 nanosheets with different facets are coated in situ onto TiO 2 nanorod (NR) substrates, where FHs are built among the nanosheets as well as between the nanosheets and NR substrates. The as‐prepared rutile TiO 2 , with an FH structure (FH‐TiO 2 ), serves as an effective photocatalyst for water splitting. More than 45 and 18 times higher photogenerated current density and H 2 production rate, respectively, are obtained compared to those of pure rutile TiO 2 NRs. Moreover, FH‐TiO 2 delivers a 0.566 mmol g −1 h −1 H 2 production rate even in pure water. This study offers important insights into the rational design of rutile TiO 2 structures for highly efficient photocatalytic reactions.