This paper presents a pyroelectric approach for the synthesis of metal–BaTiO3 hybrid nanoparticles (NPs) and demonstrates the enhanced performance on the degradation of dye solution using such hybrid NPs. During the synthesis process, rapid temperature oscillation accelerated the electron generation at the surface of pyroelectric barium titanate (BTO) NPs that were dispersed in either aqueous or nonaqueous solutions. These generated electrons were used to reduce the metal salts on the surface of BTO NPs without the need for a reducing reagent. The Au–BTO hybrid NPs synthesized by such approach showed higher pyrocatalytic degradation efficiency for dye solution than the physically mixed solutions of Au NPs and BTO NPs. Compared to conventional processes, this pyrocatalytic approach without the need for additional reducing reagents not only offers an alternative strategy for the synthesis of metal–pyroelectric hybrid materials but also opens a new way to harvest thermal energy for efficient pyrocatalysis process.
Yonghui Yang,Hengwei Yan,Zhanwei Liu,Shenghui Guo,Wenhui Ma,Mingyi Hu,Rui Xia,Wenrong Wang
This study explores a CaO-regulated thermal–electrochemical synergistic reduction approach for TiO 2 in fluoride-based molten salts, aiming to enhance deoxygenation efficiency and particle densification. At elevated temperatures, CaO reacts with TiO 2 and the NaF–K 2 TiF 6 molten salt to form CaF 2 and reactive intermediate phases, which facilitate the in situ generation of metallic Ca and alter the local redox environment. These transformations promote the complete electrochemical reduction of TiO 2 into metallic titanium through the formation and subsequent reduction of titanium oxyfluoride complexes such as K 2 NaTiOF 5 and TiOF 2 . Cyclic voltammetry reveals that CaO addition induces a negative shift in the Ti(IV)/Ti(III) redox potential, suggesting a modified reduction pathway and increased activation energy. The titanium powders synthesized at 890 °C with current densities ranging from 2.0 to 3.5 A/cm 2 exhibit reduced oxygen content down to 2900 ppm and a dense, near-spherical morphology. Microstructural analyses using FIB–SEM and EDS confirm that CaO incorporation suppresses surface oxidation and promotes particle uniformity. These findings provide mechanistic insight into the synergistic role of CaO in titanium deoxygenation and demonstrate its potential in reducing the oxygen content of titanium powders and improving their compositional uniformity.
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