Photothermally driven reaction path regulation in Ti₃C₂ MXene-based nano-thermite films for efficient laser ignition and energy release

Nano-thermite energetic films were suited to microscale laser ignition, but weak NIR absorption and low energy-use efficiency still limited practical use. Herein, we addressed these limitations by integrating Ti₃C₂ into flexible Al/Bi₂O₃ films via Direct Ink Writing (DIW). Experimental characterizations and theoretical calculations (Gibbs free energy, Bader charge analysis) indicated that Ti₃C₂ acted as a multifunctional regulator: it enhanced NIR absorption via localized surface plasmon resonance (LSPR), accelerated heat conduction, and tailors thermite reactions via a three-stage pathway (preheating, reaction and product transfer). Ultimately, by tuning the Ti₃C₂ content, the laser ignition threshold was reduced by 60.8 % and the photothermal conversion efficiency was increased to 41.43 % at 10 wt%, the reaction onset temperature was decreased by 40 °C and the maximum flame propagation/pressurization performance was achieved at 1 wt%, and the total heat release was nearly tripled at 5 wt%, indicating a comprehensive optimization of the combustion behavior. This work established a Ti₃C₂ paradigm for coupling photothermal conversion with chemical energy release, enabling low-threshold, high-response micro-igniters and miniaturized devices.