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

Rational and smart design of hydrogen (H-2) sensors especially those featured with flexibility and light weight is highly desirable, to meet the requirements for future development of portable H-2 sensors. In this work, we demonstrate a novel paper film H-2 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 H-2 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% H-2. In addition, the MXene@Pd CNC sensor enabled "in-situ-mode" H-2 detection directly along a piece of paper film with desired size. The strong H-2 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.