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Updated: Nov 5, 2025

CO2 Photoreduction to CH4 Performance Under Concentrating Solar Light
Published on: June 12, 2019
Alkali hexatitanate photocatalysts with various morphologies for selective reduction of carbon dioxide with water
Xing Zhu1, Akira Yamamoto2, Hisao Yoshida2
1Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan. yoshida.hisao.2a@kyoto-u.ac.jp.
Abstract:
Various alkali-metal hexatitanate photocatalysts were examined for photocatalytic reduction of carbon dioxide with water. Four types of alkali-metal hexatitanate samples (A2Ti6O13, A = Na, K, Rb, and Cs) were correctly prepared by either a flux method or a solid-state reaction method. Among them, the potassium hexatitanate (K2Ti6O13: KTO) photocatalyst exhibited the highest activity and selectivity to CO formation. Further development of the KTO photocatalyst was examined by changing preparation conditions such as different fluxes, the ratio of flux and substrate, and the calcination temperature, which provided various morphologies, structures, and photocatalytic activities. Among the examined samples, an Ag/KTO photocatalyst consisting of rod-like KTO crystals with a suitable length and width, prepared with a KCl flux at 1273 K for 10 hours and loaded with an Ag cocatalyst, gave the highest activity for CO evolution (4.3 μmol h-1) and the highest selectivity toward CO (96%).
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