Rapid Synthesis of A_xWO₃ (A = H, Na, K) Tungsten Bronze Materials with Strong Near-Infrared Absorption and Enhanced Photoelectric Anticorrosion Properties

The intrinsic reduction method is extended for the synthesis of tungsten bronzes (TBs), and monoclinic phase hydrotungsten bronze (HWO), tetragonal phase sodium tungsten bronze (NaWO) and hexagonal phase potassium tungsten bronze (KWO) are obtained. The introduction of cations brought a large number of localized state free electrons, which endowed TBs with strong near-infrared (NIR) absorption and achieved light energy utilization covering almost the entire solar spectrum in the form of localized surface plasmon resonance (LSPR) and small polariton transfer. The strong NIR absorption enhanced the corrosion protection performance of tungsten bronze coatings, especially the HWO coating, which had an increased impedance value of 859.5% compared to the pure epoxy resin. The excellent corrosion resistance of TBs inhibitors can be derived from the strong NIR absorption enhanced photocathodic protection and local magnetic field, which improved the charge transfer resistance of the coating by nearly two orders of magnitude and greatly inhibited the charge movement in the electrochemical corrosion reaction. This study discovered the contribution of oxygen vacancy-enhanced NIR absorption to the electrochemical anticorrosion properties, expanding the application area of TBs and making an important contribution to innovative anticorrosion strategies.