Surface reduction boosts free electron concentration in MXene for enhanced photothermal performance.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 42127176.
- Also identified by DOI 10.1126/sciadv.aee2009 and PMC identifier 13170662.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The photothermal properties of MXenes originate from the localized surface plasmon resonance, which is attributed to their high free electron concentration. However, their intrinsic electron concentration is limited by suboptimal d-orbital occupancy and the electron-withdrawing effect from electronegative terminations. Herein, we report a sodium-mediated surface reduction strategy in molten salts, which optimizes the surface coordination environment via electronic modulation to mitigate the electron-withdrawing and electron-scattering effects, while simultaneously injecting electrons into the Ti-3d states for controlled state filling. This dual modulation enables the free electron concentration, carrier mobility, and electrical conductivity to reach 4.92, 2.63, and 12.96 times that of the pristine MXene, respectively. The optimized reduced Ti<sub>3</sub>C<sub>2</sub> achieves a high photothermal conversion efficiency of 91.66% under 808-nanometer laser irradiation. A photothermal antibacterial woundplast with ultralow MXene content demonstrates a high bacterial kill rate. This work not only shows an effective method for tuning the photothermal properties of MXenes but also inspires applications that require tailored surface chemistry and high electron concentration.