Photocatalytic conversion of greenhouse gases (CO2 and CH4) using copper phthalocyanine modified TiO2

In the present study, the direct photoconversion of carbon dioxide and methane in an appropriate gas-phase batch reactor under visible light was investigated. In the photocatalytic reaction system copper phthalocyanine (CuPc) modified titanium dioxide (CuPc/TiO2) photocatalyst that was coated on stainless steel mesh was used. The morphology of CuPc/TiO2 photocatalysts were characterized using XRD, SEM, FTIR and UV-vis analyses, and photoreduction products were identified using GC-TCD, GC-MS and FTIR in gas medium. The results of SEM have shown limited presence of CuPc on TiO2 surface, also the results of UV-vis have shown that the absorbance spectra of titania extended to visible spectral region. The results of photocatalytic activity have shown the conversion of 14% and 18% for CO2 and CH4 under modified TiO2 and visible light, respectively. However, the conversions of CO2 and CH4 under unmodified TiO2 and visible light were zero, approximately. Based on GC-MS and FTIR analyses, final products of conversion were characterized to be formate and acetate derivatives, and a mechanism involving the photoactivation of both TiO2 and CuPc sensitizer is proposed. (C) 2013 Elsevier B.V. All rights reserved.