TiN/anatase/rutile phase junction obtained by in-situ thermal transformation for efficient photothermal-assisted photocatalytic hydrogen generation.

Phase junctions exhibit great potential in photocatalytic energy conversion, yet the narrow light response region and inefficient charge transfer limit their photocatalytic performance. Herein, an anatase/rutile phase junction modified by plasmonic TiN and oxygen vacancies (TiN/(A-R-TiO-Ov)) is prepared through an in-situ thermal transformation from TiN for efficient photothermal-assisted photocatalytic hydrogen production for the first time. The content of TiN, oxygen vacancies, and phase components in TiN/(A-R-TiO-Ov) hybrids can be well-adjusted by tuning the heating time. The as-prepared photocatalysts display a large specific area and wide light absorption due to the synergistic effect of plasmonic excitation, oxygen vacancies, and bandgap excitations. Meanwhile, the multi-interfaces between TiN, anatase, and rutile provide built-in electric fields for efficient separation of photoinduced carriers and hot electron injection via ohmic contact and type-Ⅱ band arrangement. As a result, the TiN/(A-R-TiO-Ov) photocatalyst shows an excellent photocatalytic hydrogen generation rate of 15.07 mmol/g/h, which is 20.6 times higher than that of titanium dioxide P25. Moreover, temperature-dependent photocatalytic tests reveal that the excellent photothermal conversion caused by plasmonic heating and crystal lattice vibrations in TiN/(A-R-TiO-Ov) has about 25 % enhancement in photocatalysis (18.84 mmol/g/h). This work provides new inspiration for developing high-performance photocatalysts by optimizing charge transfer and photothermal conversion.