High-performance gas-sensor fabricated with Ti₃C₂T_x ternary composites decorated with Pd and SnO₂ dual-type nanoparticles for room-temperature hydrogen detection

Hydrogen plays a vital role in zero-carbon energy systems and lithium-ion battery health monitoring, while its safe utilization faces a critical challenge in achieving high-accuracy room-temperature detection with fast response speed. Herein, Ti₃C₂T_x ternary composites decorated with Pd and SnO₂ nanoparticles (MPS) are successfully synthesized via a facile approach at 80 ˚C with a high hydrogen sensitivity based on a synergetic effect. Within the MPS composites, the dissociation energy barrier for hydrogen molecules can be drastically reduced with the existence of Pd nanoparticles, boosting the ionization of active hydrogen atoms at the heterointerface between SnO₂ and MXene via the hydrogen spillover effect. The isomorphous substitution of Ti^{3 +} by Sn⁴⁺ generates abundant holes at the heterointerface, and the built-in electric field formed at the heterointerface subsequently promotes the recombination of these holes with the electrons generated during hydrogen ionization. Benefitting from the series of reaction, the optimal response of 73.5% is obtained with fast response/recovery time of 47 s/36 s upon exposure to 200 ppm H₂ at room-temperature. In addition, an outstanding linearity (R²=0.9908) is achieved within a range between 5 and 200 ppm, resulting in a superior LOD of 1.96 ppm. The MPS composite gas sensor simultaneously exhibits exceptional selectivity and cycling stability, shedding light on the new perspective of high-performance room-temperature gas sensing.