Ti3C2 MXene-derived sodium titanate nanoribbons for conductometric hydrogen gas sensors

Among various requirements for safety H2 sensors, response time has been set the most stringent target because fast response speed is vital to initial leakage detection. However, this requirement still remains quite challenging to achieve. Herein, the ultrafast H2 sensing behavior of Pd-decorated sodium titanate nanoribbons (Pd-NTO NRs) is reported for the first time. Ti3C2 MXene is used as precursor to prepare NTO NRs, which are then uniformly decorated with Pd nanoparticles (NPs), forming Pd-NTO NRs. The as-prepared material has a series of unique physical and chemical features that synergistically accelerate the H2 response speed, such as laterally paralleled morphology, abundant oxygen vacancies on edge sites of NTO NRs and monodispersed Pd NPs. Benefiting from all this advantages, the as-prepared Pd-NTO NRs show an ultrafast response to 1% H2 within 1.1 s at room temperature that outperforms the state-of-the-art electrical H2 sensors, and a wide detection range (0.8 ppm-10% H2), demonstrating a promising application prospect in safety H2 sensors. The sensing mechanism based on chemical sensitization are carefully discussed, which highlights the distinctive structural and chemical characteristics of NTO NRs for synergistically boosting the H2 response speed.