Prismatic TaN-composed spheres produced by self-sacrificial template-like conversion of Ta particles NaCO flux

• Published in: CrystEngComm 2020-08, Vol.22 (31), p.5122-5129
• Main Authors: Suzuki, Sayaka, Ando, Ryota, Matsui, Yusaku, Isechi, Katsunori, Yubuta, Kunio, Teshima, Katsuya
• Format: Article
• Language: English
• ISSN: 1466-8033
• DOI: 10.1039/d0ce00589d

Spatial charge separation on the anisotropic facets of photocatalyst particles can enhance their photocatalytic performance by reducing the probability of electron-hole recombination. This study investigated the Na 2 CO 3 flux growth of faceted Ta 3 N 5 crystals using Ta powders as the Ta source. An extremely small amount of Na 2 CO 3 flux led to the growth of well-formed prismatic Ta 3 N 5 crystals as a single-phase. The prismatic crystals formed spherical aggregates with a size and shape similar to those of the raw Ta powders. Although Ta 3 N 5 crystals were also grown from Ta 2 O 5 and TaCl 5 in Na 2 CO 3 flux, the products were neither well-formed particles nor single-phase Ta 3 N 5 , which suggests that Ta powder dissolved more easily in Na 2 CO 3 flux. The growth mechanism of the spherical Ta 3 N 5 aggregates was investigated by evaluating the crystal growth at different heating temperatures and times. Cross-sectional observation of the products indicated that the raw Ta powder grains acted as a self-sacrificial template, thus determining the size and shape of the final product. The Ta 3 N 5 crystals modified with CoO x co-catalysts exhibited photocatalytic activity for O 2 evolution under visible light irradiation. Ta 3 N 5 crystals were grown from Na 2 CO 3 flux using spherical Ta powders.