著者

Takayama Tomoaki Iwase Akihide Kudo Akihiko

出版者

The Chemical Society of Japan

雑誌

Bulletin of the Chemical Society of Japan (ISSN:00092673)

巻号頁・発行日

2015

被引用文献数

46

---

Single-crystal KCaSrTa₅O₁₅ nanorods were successfully synthesized by a polymerized complex method. SEM and TEM observations revealed that the nanorods growing along with the c-axis of the tungsten bronze structure possessed 40–100 nm of a diameter and 100–300 nm of a length. Tb(0.03 atom%)-doped KCaSrTa₅O₁₅ nanorods gave a green luminescence due to the ⁵D₄→⁷F₆ and ⁵D₄→⁷F₅ transition of Tb³⁺, when the KCaSrTa₅O₁₅ host was excited. The intensity of the luminescence was much higher than that by polycrystalline KCaSrTa₅O₁₅ prepared by a solid-state reaction. This indicates that nonradiative deactivation at grain boundaries was suppressed in the KCaSrTa₅O₁₅ nanorods compared to the polycrystalline KCaSrTa₅O₁₅. NiO cocatalyst-loaded KCaSrTa₅O₁₅ nanorods split water into H₂ and O₂ with 6.6% of an apparent quantum yield at 254 nm. The efficiency was three times higher than that of the polycrystalline KCaSrTa₅O₁₅. The KCaSrTa₅O₁₅ nanorods also showed photocatalytic activity for CO₂ reduction, when a Ag-cocatalyst was loaded. Stoichiometric amounts of CO and H₂ as reduction products and O₂ as an oxidation product were obtained. The activity for CO₂ reduction was improved by adding NaHCO₃ into the reactant solution, giving about 90% of a CO selectivity (CO/(CO+H₂)).