Truncated octahedral bipyramidal TiO 2 /MXene Ti 3 C 2 hybrids with enhanced photocatalytic H 2 production activity.

MXene Ti 3 C 2 /TiO 2 hybrids were successfully synthesized through a simple calcination of F-terminated Ti 3 C 2 . The resultant Ti 3 C 2 /TiO 2 composite photocatalysts retained a 2D multilayer structure like MXene Ti 3 C 2 , and TiO 2 exhibited a truncated octahedral bipyramidal structure with exposed (001) facets under the participation of fluorine ions. The residual Ti 3 C 2 could act as a co-catalyst to enhance the photocatalytic H 2 production activity by capturing photogenerated electrons from TiO 2 because of its electron reservoir feature and suitable Fermi level. The (101)-(001) surface heterojunction of the truncated octahedral bipyramidal TiO 2 further accelerated the separation of photogenerated carriers. As a result, the Ti 3 C 2 /TiO 2 hybrids with calcining F-terminated Ti 3 C 2 exhibited photocatalytic hydrogen production that is twofold higher than that of Ti 3 C 2 /TiO 2 hybrids with calcining OH-terminated Ti 3 C 2 . This work presented a new strategy to prepare MXene Ti 3 C 2 /TiO 2 hybrids for photoconversion applications.