Efficient Z-Scheme heterostructure based on TiO2/Ti3C2Tx/Cu2O to boost photoelectrochemical response for ultrasensitive biosensing

In this work, a Z-scheme TiO2/Ti3C2Tx/Cu2O heterostructure was well designed and fabricated by in situ generating TiO(2)NPs on Ti3C2Tx MXenes and subsequently introducing Cu2O via one-step hydrothermal reaction. The obtained heterojunction exhibits good photoelectrochemical (PEC) activity with dissolved O-2 as electron scavenger, during which H2O2 is produced as intermediates to further capture the photo generated electrons. However, H2O2 is consumed with the addition of glucose, leading to the accumulation of photoelectrons on the heterojunction and a significant decay in the photocurrent signal. On this basis, TiO2/Ti3C2Tx/Cu2O was employed as photocathode to construct a self-powered PEC sensor for glucose detection, and the photocurrent of TiO2/Ti3C2Tx/Cu2O linearly decreased with the increasing logarithm of glucose concentration in a wide range of 100 nM to 10 mu M with a low detection limit of 33.75 nM (S/N = 3). Moreover, the fabricated PEC sensor possessed favourable feasibility and high selectivity for the determination of glucose in biomedical samples, suggesting a bright future in the application of clinical diagnosis.