Synthesis of One-Dimensional Potassium Tungsten Bronze with Excellent near-Infrared Absorption Property

Potassium tungsten oxide nanofibers were successfully synthesized via a facile hydrothermal reaction route in the presence of sulfate. After reduction under a reductive atmosphere of H-2(5 vol %)/N-2, the potassium tungsten oxide transformed to potassium tungsten bronze. Because of the lack of free electrons, the potassium tungsten oxide (KxWO3+x/2) showed no NIR shielding performance; however, the potassium tungsten bronze (KxWO3) showed promising optical characteristics such as high transmittance for visible light, as well as high shielding performance for near-infrared lights, indicating its potential application as a solar filter. Meanwhile, the potassium tungsten bronze (KxWO3) showed strong absorption of near-infrared light and instantaneous conversion of photoenergy to heat.