3D printing of molecularly-imprinted Ti3C2 MXene-derived hierarchically porous sensing platform toward ultrasensitive photoelectrochemical monitoring

Photoelectrode configuration with well-interconnected micro- and nanochannels is essential and critical to high-performance photoelectrochemical microelectrode monitoring. However, challenges remain pertaining to consistent manufacturing, prominent light absorption and highly efficient analyte trapping. Herein, with Ti3C2 MXene-derived TiO2-Ti3C2 as photoactive material, a novel fiber-shaped graphene (G)/TiO2-Ti3C2/molecularly imprinted polyaniline (MIP-PANI) photoelectrochemical phenol sensor was constructed via a facile and controllable direct ink writing (DIW) 3D printing strategy. The resulting 3D-printed sensor demonstrated enriched well-interconnected hierarchical pores built by jointing tortuous photoactive 2D G sheets and uniform anchoring of MIP-PANI thin layer onto pore wall, thereby facilitating high light absorption, and meanwhile guaranteeing sufficient specificity binding sites for rapid analyte trapping. Benefiting from these remarkable features, such sensing platform delivered a low detection limit (0.4 µM) with linear range of 8–130 µM, and displayed rapid response, outstanding selectivity and perfect working performance during bending. This work has shed light on new strategies for fabricating rational photoelectrode configurations toward high-performance photoelectrochemical microelectrode sensors.