Photocatalytic H2 Evolution on TiO2 Assembled with Ti3C2 MXene and Metallic 1T-WS2 as Co-catalysts

<jats:title>Abstract</jats:title><jats:p>The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst’s surface. In this paper, we report that double metallic co-catalysts Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> MXene and metallic octahedral (1T) phase tungsten disulfide (WS<jats:sub>2</jats:sub>) act pathways transferring photoexcited electrons in assisting the photocatalytic H<jats:sub>2</jats:sub> evolution. TiO<jats:sub>2</jats:sub> nanosheets were in situ grown on highly conductive Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> MXenes and 1T-WS<jats:sub>2</jats:sub> nanoparticles were then uniformly distributed on TiO<jats:sub>2</jats:sub>@Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> composite. Thus, a distinctive 1T-WS<jats:sub>2</jats:sub>@TiO<jats:sub>2</jats:sub>@Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> composite with double metallic co-catalysts was achieved, and the content of 1T phase reaches 73%. The photocatalytic H<jats:sub>2</jats:sub> evolution performance of 1T-WS<jats:sub>2</jats:sub>@TiO<jats:sub>2</jats:sub>@Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> composite with an optimized 15 wt% WS<jats:sub>2</jats:sub> ratio is nearly 50 times higher than that of TiO<jats:sub>2</jats:sub> nanosheets because of conductive Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> MXene and 1T-WS<jats:sub>2</jats:sub> resulting in the increase of electron transfer efficiency. Besides, the 1T-WS<jats:sub>2</jats:sub> on the surface of TiO<jats:sub>2</jats:sub>@Ti<jats:sub>3</jats:sub>C<jats:sub>2</jats:sub> composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site.</jats:p>