Synthesis and characterization of potassium hexatitanate using boric acid as the flux

Crystalline Structure, Synthesis, Properties and Applications of Potassium Hexatitanate: A Review

“…Yahya et al too reported a H 2 evolution rate from H 2 O of up to 47 µmol/h in samples prepared with the loaded ruthenium oxide on PHT [97]. Likewise, Hakuta et al [31] report the use of PHT nanowires (prepared by hydrothermal method) with large surface area (up to 219.8 m 2 /g) and high photocatalytic activity, in the reaction of photolysis of methane; the amount of hydrogen generated by the use of this material was approximately 0.2 µmol in a reaction time of 8 hours. Moreover, Guan et al [98] have reported the photoreduction of CO 2 with water into methanol under concentrated sunlight using a Pt-loaded PHT photocatalyst or a composite catalyst in which the Pt-PHT photocatalyst was combined with a CO 2 hydrogenation catalyst of Cu/ZnO.…”

“…This type of structure promotes whisker or fiber crystalline growth and provides the characteristics for different applications such as reinforcement agents, thermal insulators, photocatalyst, etc. [13,[27][28][29][30][31]. PHT crystallizes in the monoclinic system with space group C2/m; it has a tunnel-like structure formed by titania octahedra enclosing the atoms of K [24,25]; K2Ti6O13 crystals include two variants of the chemical formula (K2O.6TiO2 and K2Ti6O13) and a content of 42 atoms of which four are potassium (K), 12 titanium (Ti) and 26 oxygen (O).…”

“…This type of structure promotes whisker or fiber crystalline growth and provides the characteristics for different applications such as reinforcement agents, thermal insulators, photocatalyst, etc. [13,[27][28][29][30][31]. Besides, it also has been reported that PHT prepared both hydrothermal and solid-state conditions presents similar absorption bands observed in the FTIR, which are at 457 cm −1 , 500 Besides, it also has been reported that PHT prepared both hydrothermal and solid-state conditions presents similar absorption bands observed in the FTIR, which are at 457 cm −1 , 500 cm −1 , 713 cm −1 , and 760 cm −1 ; the frequency at 713 cm −1 corresponds to TiO 6 group and that at 470 −510 cm −1 corresponds to Ti-O [32].…”

“…Similarly, the optical properties of the PHT for catalytic applications were investigated, e.g., in photocatalytic degradation, photocatalytic water splitting, and steam reforming of methane for hydrogen production. Researchers determined (theoretical and experimentally) the bandgap value of the PHT and the results showed that this material is a wide-broad semiconductor, and it presents a bandgap similar to the TiO 2 [27,31,[34][35][36][37]. Table 2 summarizes the physical and mechanical properties of PHT registered in literature, while Table 3 shows several bandgap data where the values vary slightly according to the method of synthesis.…”

“…The obtained material is dried, grounded in agate mortar (mesh-80, 180 µm), washed in hot water (95 • C) to remove the remaining flux and dried. Finally, the product is thermally treated between 900 and 1000 • C for 2 h. Figure 3 shows the PHT micrometric fibers obtained from this method [31].…”