[1Ha01-04] Environmental Material/Energy Material (SU/EN)

[1Ha02] Effect of crystal phases and defect formation on photocatalysis of reduced Pt/ZrO_2−x

*Naoto Doshita¹, Yukari Yamazaki¹, Kohsuke Mori¹, Yasutaka Kuwahara¹, Hiromi Yamashita¹ (1. Graduate School of Engineering, Osaka University)

Zirconium oxide (ZrO₂) has attracted attention as a catalyst material, which exhibits activity in various reactions because of its excellent chemical properties. On the other hand, it has a large band gap of about 5 eV, making it difficult to utilize sunlight as a photocatalyst. Reduced ZrO_2−x, in which oxygen vacancies (V_O) or Zr³⁺ are formed, is one of the promising materials which exhibit photocatalytic activity by defect formation. Monoclinic (m-) and Tetragonal (t-) ZrO₂ can exist stably under mild conditions, which makes them suitable for catalytic reaction. In this study, we investigated the effect of crystal phases and defect formation on the photocatalytic activity. ZrO₂ was synthesized by solvothermal method, and Pt/ZrO_2−x were then obtained via reduction treatment under H₂. In photocatalytic H₂ production, Pt/m-ZrO_2−x exhibited a higher activity than Pt/t-ZrO_2−x. In addition, for both crystal phases, the Pt/ZrO_2−x reduced at 600 °C for 2 hours exhibited the highest activity.