A comparative study of H 2 sensing performance of stoichiometric polymorphs of titanium carbide MXenes loaded with Pd nanodots

Although titanium-based MXenes have been widely reported for gas sensing, the effect of crystal stoichiometric variations on the sensing properties has been rarely reported. Herein, stoichiometric polymorphs of titanium carbide MXenes ( , Ti C T and Ti CT ) loaded with Pd nanodots (NDs) prepared by photochemical reduction were investigated for room-temperature H sensing. Interestingly, we found that Pd/Ti CT exhibited greatly enhanced sensitivity to H , along with faster response and recovery rates compared to Pd/Ti C T . The H adsorption induced resistance change in Pd/Ti CT was higher than that of Pd/Ti C T due to the more effective charge transfer at the heterointerface of Pd/Ti CT , which was confirmed by shifts of binding energies and theoretical calculation results. We hope this work could be helpful to design more high-performance MXene-based gas sensors.