PtO nanodots promoting Ti₃C₂ MXene in-situ converted Ti₃C₂/TiO₂ composites for photocatalytic hydrogen production

Increasing the separation efficiency of photogenerated carriers and preventing the hydrogen back oxidation are two key challenges in photocatalytic hydrogen production. Herein, we report a promising PtO@Ti₃C₂/TiO₂ photocatalyst to overcome these two challenges by in-situ growing TiO₂ nanosheets on Ti₃C₂ MXene (to improve charge separation) and depositing PtO nanodots (to diminish hydrogen back reaction) for enhanced photocatalytic hydrogen production. Within this design principle, the photogenerated electrons and holes in the PtO@Ti₃C₂/TiO₂ composites flow in opposite direction into PtO and Ti₃C₂ respectively, resulting in effective separation of the photogenerated electrons and holes. Beyond, the higher oxidation state of PtO nanodots also largely suppresses the undesirable hydrogen back oxidation reaction. Thereby the PtO@Ti₃C₂/TiO₂ composite demonstrates remarkable hydrogen production efficiency. Our work here indicates that rational design of dual co-catalysts could not only promote the separation of photogenerated carriers for enhanced hydrogen production, but also inhibit the reverse reaction of hydrogen production.