A novel Zn–TiO₂/C@SiO₂ nanoporous material on rice husk for photocatalytic applications under visible light

Abstract

A series of self-nitrogen-doped and Zn-doped TiO₂/C@SiO₂ (ZTRH) nanoporous composites with high surface area and excellent biological hierarchical porous structure have been synthesized by sol–gel method at different temperatures. The porous SiO₂ and activated carbon from the decomposition of rice husk (RH) were regarded as the template and porous catalytic carrier. The structure, crystallinity, morphology, and other physical–chemical properties of the samples were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transforminfrared spectroscopy, N₂ adsorption–desorption isotherms, and UV–vis diffuse reflectance spectroscopy. The feasibility of ZTRH nanoporous composites for decomposing pollutants was evaluated by rhodamine B under visible light irradiation. Compared with the traditional photocatalytic materials, ZTRH nanoporous materials not only performed high efficiency in pollutants degradation, but also exhibited good adsorption properties. Moreover, since RH ash acts as the catalyst support, the composites are easily recycled after catalysis reaction. The ZTRH nanoporous composites could be applied to the wastewater with different pH values and be regarded as a kind of promising recyclable photocatalyst in photodegradation of pollutants in water.

Keywords:

• Zn-doped TiO₂/C@SiO₂
• Rice husk
• Photocatalyst
• Visible light

Acknowledgments

The authors thank the financial support from the New Century Excellent Talents in University (NCET-10-0137) and Department of Science and Technology of China (2012CBT22T02). This work was financially supported by the Scientific Research Foundation of Education Commission of Hubei Province (Q20111010 and T201101), the Natural Science Foundation of Hubei Province (2011CDB059 and 2011CDA111), the Research Fund for the Doctoral Program of Higher Education of China (20114208120006) for Dr Yu He.