Flexible and lightweight Ti3C2Tx MXene@Pd colloidal nanoclusters paper film as novel H2 sensor.

Rational and smart design of hydrogen (H2) sensors especially those featured with flexibility and light weight is highly desirable, to meet the requirements for future development of portable H2 sensors. In this work, we demonstrate a novel paper film H2 sensor employing Ti3C2Tx MXene nanosheets with Pd colloidal nanoclusters (Pd CNC) as the activator. The MXene@ Pd CNC paper film was facilely prepared via an all-colloidal solution-based vacuum-filtration process, which is flexible, light-weight and endowed with a compact, glossy surface. The as-obtained MXene@ Pd CNC film sensor displayed moderate H2 response at room temperature at either flat or bent states. Specially, the MXene@Pd CNC film sensor delivered a response time of (32 ± 7) s and a sensitivity of S = (23.0 ± 4.0)%@4% H2. In addition, the MXene@Pd CNC sensor enabled "in-situ-mode" H2 detection directly along a piece of paper film with desired size. The strong H2 adsorption into lattice of ultrafine Pd CNC altered the work function thus induced the electron doping of MXene, which explained the gas sensing mechanism. Therefore, the facilely designed MXene@Pd CNC sensor is believed to contribute to development of future portable and wearable sensing electronics.