Abstract
In this paper, the photocatalytic activity of nitrogen-doped TiO2/montmorillonite composite (NTM) was successfully enhanced by modification with carbon. NTM was made by mixing a swelling clay solution with an N-doped TiO2 solution prepared by hydrolysis of titanium tetraisopropoxide with urea. Carbon-modified N-doped TiO2/montmorillonite composite (CNTM) was obtained by grinding the dried NTM with EtOH for 1 h, followed by calcination at 250°C in the air for 2 h. Both NTM and CNTM exhibited visible light absorption in the UV–vis spectrum in the same way as commercial N–TiO2 powder. Additionally, CNTM greatly extended the absorption edges to the visible light region. The photocatalytic performance of NTM and CNTM was evaluated using a degradation of bisphenol-A under visible light (>420 nm) radiation. Although the commercial TiO2 powder showed less photocatalytic activity under visible light radiation, NTM, CNTM and commercial N–TiO2 powder showed high photocatalytic activity. The order of degradation performance was as follows: CNTM > commercial N–TiO2 powder > NTM. Since the TiO2 content of CNTM is ca. 30 mass % by energy dispersive spectrum analysis, it was suggested that CNTM has extremely high visible light activity.
