LAUSR

Abstract Heterojunctions are usually designed as photocatalytically active interfaces to promote the separation of photo-induced charge carriers. In situ construction of a heterojunction using nucleation sites derived from the same precursor effectively enhances the extent to which there is heterogeneous contact throughout the whole mixture, compared with heterojunction formation between two completely crystalline phases. In this work, (001)TiO2/Ti3C2 heterojunctions were successfully fabricated through simple hydrothermal oxidation of the Ti3C2 precursor and used as an electrode material for the photoelectrochemical (PEC) detection of dopamine. The (001)TiO2 formed on the surface of Ti3C2 using Ti3C2 itself as the source of titanium not only increases the catalytically active surface (001 facet) for dopamine adsorption, but also produces a superior photoelectric response (compared to TiO2) based on the coupling effect of (001)TiO2 and the two-dimensional Ti3C2 inhibiting the recombination of electron–hole pairs. The PEC sensor can detect dopamine from 1.0 μM to 1000 μM with a limit of detection of 0.52 μM, with good stability, and high selectivity. This work therefore suggests that (001)TiO2/Ti3C2 heterojunctions represent a promising material for applications in PEC detection.