Photocatalytic reduction of CO₂ using H₂ as reductant over ATaO₃ photocatalysts (A = Li, Na, K)

详细信息    查看全文

• 作者：Kentaro Teramura ; Shin-ichi Okuoka ; Hideo Tsuneoka ; Tetsuya Shishido ; Tsunehiro Tanaka
• 关键词：Photocatalysis ; CO₂ reduction ; Solid base
• 刊名：Applied Catalysis B: Environmental
• 出版年：2010
• 出版时间：7 June 2010
• 年：2010
• 卷：96
• 期：3-4
• 页码：565-568
• 全文大小：640 K

文摘

ATaO₃ (A = Li, Na, K) compound oxides exhibit photocatalytic activity for the reduction of CO₂ in the presence of H₂. Only CO gas was generated over all samples under photoirradiation. The photocatalytic activity was higher in the order corresponding to KTaO₃, NaTaO₃ and LiTaO₃ (LiTaO₃ > NaTaO₃ > KTaO₃). The order of the photocatalytic activities was consistent with that of the E_g (optical gap) values. After 24 h of photoirradiation, the amount of evolved CO reached 0.42 μmol g⁻¹ over LiTaO₃. TPD experiments indicated that the broad peak which is assigned to chemisorbed CO₂ gas was observed at 573 K in the case of LiTaO₃. On the contrary, there was no peak in the spectra of NaTaO₃ and KTaO₃. The amount of evolved CO gas almost strongly depends on the amount of chemisorbed CO₂ in the case of ATaO₃ (A = Li, Na, K). In addition, the photocatalytic activity increased with increasing the calcination temperature of LiTaO₃. This means that a smooth charge separation in a LiTaO₃ photocatalyst and chemisorption of CO₂ on the surface contribute to effective reduction of CO₂ in the presence of H₂.