Self-Supported MXene V₄C₃-Derived VO₂ Thermochromic Smart Window Materials: In Situ Synthesis and Performance Enhancement

Vanadium dioxide (VO2) is a promising material for smart windows due to its metal–insulator transition that enables dynamic solar transmittance modulation. In this study, VO2 (M) nanoparticles were synthesized using a novel approach involving the self-supported structure of V4C3 MXene derived from V4AlC3. Through selective etching, solvothermal oxidation and annealing, VO2 (M) nanoparticles with enhanced thermochromic properties were produced. The self-supported structure of V4C3 MXene significantly reduced particle agglomeration and improved crystallinity, resulting in VO2 (M) films with a luminous transmittance (Tlum) of up to 58.3% and a solar modulation ability (ΔTsol) of 6.3%. The study also demonstrated that film thickness and hydrogen peroxide concentration critically influence optical and thermochromic performance. This study provides a new approach for the preparation of MXene-based VO2 thermochromic smart window materials and is expected to promote their application in the field of building energy conservation.