One-step synthesis and its mechanism of potassium hexatitanate whiskers from potassium dititanate and metatitanic acid

The high price of potassium hexatitanate (K₂Ti₆O₁₃) whiskers restricts its broad applications. The current production method is composed of complex processes and generates a large amount of wastewater. In this work, we propose a new one-step synthesis approach for producing potassium hexatitanate whiskers. Potassium dititanate and metatitanic acid are mixed at the ratio of TiO₂/K₂O = 4 and then calcined at 1000 °C to synthesize potassium hexatitanate whiskers. We used XRD, SEM, TG-DSC, and other characterization techniques combined with thermodynamic calculations to study the synthesis mechanism of such one-step process. The thermodynamic calculations show that the reaction free energy of K₂Ti₆O₁₃ whiskers synthesized by this process is negative even at room temperature, confirming that this process has a higher reactivity than the conventional synthesis approach by K₂CO₃ and TiO₂. Moreover, the melting of K₂Ti₂O₅ at 916 °C provides a necessary environment for the crystal growth of K₂Ti₆O₁₃ nanoparticles, which is the key to the preparation of K₂Ti₆O₁₃ whiskers. This new synthesis approach will significantly reduce the producing cost of K₂Ti₆O₁₃ whiskers, thereby expanding its applications.