Construction of rutile/anatase Ohmic heterojunction of TiO2/Ti3C2 with robust built-in electric field for boosting photocatalytic organic pollutant and hydrogen evolution.

[Display omitted] • The optimal temperature of 500 °C resulted in a mixture of rutile and anatase with a ratio of 32:68. • The TC degradation efficiency reached 93.4 ± 1.2 % within 180 min. • The optimal hydrogen evolution efficiency was up to 784 ± 6 μmol·g−1·h−1. • The interfacial electric field promoted the separation of charges between TiO 2 and Ti 3 C 2. • Rutile/anatase heterojunction promoted the separation of photogenerated electrons and holes. A rutile/anatase Ohmic heterojunction of TiO 2 /Ti 3 C 2 was prepared through calcination. By adjusting the calcination temperature, the loading amount of TiO 2 on Ti 3 C 2 and the ratio of rutile/anatase phases could be controlled. The optimal temperature of 500 °C resulted in a mixture of rutile and anatase with a ratio of 32:68. Under visible light, the TiO 2 /Ti 3 C 2 -500 exhibited significantly superior performance in both TC degradation and hydrogen evolution compared to P25 TiO 2. The TC degradation efficiency reached 93.4 ± 1.2 % within 180 min. The optimal hydrogen evolution efficiency was up to 784 ± 6 μmol·g−1·h−1. The presence of oxygen vacancies (OV) on the TiO 2 surface provided more active sites, extended the light absorption range, and facilitated the generation of electron-hole pairs. The strong interfacial electric field effectively promoted the separation of space charges between Ti 3 C 2 and TiO 2. Additionally, the two-dimensional Ti 3 C 2 nanosheets, as an Ohmic-junction, provided more electron transfer pathways and a large number of active sites for photocatalysis. Furthermore, the formed rutile/anatase heterojunction facilitated strong electron transfer from anatase to rutile and spontaneous electron transfer from rutile to anatase. [ABSTRACT FROM AUTHOR]