Electrons-Donating Derived Dual-Resistant Crust of VO2 Nano-Particles via Ascorbic Acid Treatment for Highly Stable Smart Windows Applications.

Traditional vanadium dioxide (VO2) material faced severe challenges of low stability in acid, humid and oxygenic environments, which hinder its real applications. Here, we report a facile improving process which can enhanced the stability of VO2 nanocrystals in the environments above. Ascorbic acid (AA), as an important antioxidant for organism in medicine and biology, was ingeniously used for enhancing the anti-oxidation abilities of inorganic material. At the same time, the AA could generate the hydrogen doping occurred on the surface of VO2 nanocrystals, which enhanced their anti-acid abilities simultaneously. The AA treated VO2 nanocrystals retain stable in H2SO4 and H2O2 solution and exhibit high durability in hyperthermal (60 oC) and humid (90%) environment. Characterizations and first-principle theoretical calculations confirmed that the coordination of ascorbic acid molecules on VO2 nanocrystals induced charge-carrier density reorganization and protons transferring electrostatically. Then the formed HxVO2 provides an enhancing formation energy for oxygen vacancy and protects the particles from corrosion. This work is beneficial to the VO2 nanoparticles coated and decorated processes and exhibit good potential for practical application of VO2-based smart windows.