Truncated octahedral bipyramidal TiO₂/MXene Ti₃C₂ hybrids with enhanced photocatalytic H₂ production activity

MXene Ti₃C₂/TiO₂ hybrids were successfully synthesized through a simple calcination of F-terminated Ti₃C₂. The resultant Ti₃C₂/TiO₂ composite photocatalysts retained a 2D multilayer structure like MXene Ti₃C₂, and TiO₂ exhibited a truncated octahedral bipyramidal structure with exposed (001) facets under the participation of fluorine ions. The residual Ti₃C₂ could act as a co-catalyst to enhance the photocatalytic H₂ production activity by capturing photogenerated electrons from TiO₂ because of its electron reservoir feature and suitable Fermi level. The (101)-(001) surface heterojunction of the truncated octahedral bipyramidal TiO₂ further accelerated the separation of photogenerated carriers. As a result, the Ti₃C₂/TiO₂ hybrids with calcining F-terminated Ti₃C₂ exhibited photocatalytic hydrogen production that is twofold higher than that of Ti₃C₂/TiO₂ hybrids with calcining OH-terminated Ti₃C₂. This work presented a new strategy to prepare MXene Ti₃C₂/TiO₂ hybrids for photoconversion applications.