I, N-Codoping Modification of TiO2 for Enhanced Photoelectrochemical H2O Splitting in Visible-Light Region

Abstract

The donor–acceptor codoping is an effective approach to tune the photoelectrochemical properties of TiO2. Here, we systematically investigate the effects of (I+N) codoping on the electronic structures and H2O splitting reactions of anatase TiO2 by using density functional theory. It is found that the codoping of the stable charge-compensated (I+N) donor–acceptor pair in anatase TiO2 not only can prevent the recombination of photogenerated electron–hole pairs but also can effectively reduce the band gap to 2.251 eV by forming an intermediate band within the band gap. The band edge alignment of (I+N) codoped TiO2 is desirable for H2O splitting, and the calculated optical absorption curve of (I+N) codoped TiO2 verifies that (I+N) codoping can significantly improve visible-light absorption. Moreover, we also calculate the chemical reaction pathways of H2 generation via H2O splitting on (I+N) codoped TiO2 surfaces by using the climbing nudged elastic band (cNEB) method and find that the (I+N) codoping in TiO2 ...