The effects of Co / Ce loading ratio and reaction conditions on CDRM performance of Co-Ce / ZrO2 catalysts

This work mainly aims to establish a link between Co/Ce loading ratio in Co-Ce/ZrO2 catalysts and their Carbon Dioxide Reforming of Methane (CDRM) performance. In this context, catalysts with different Co and Ce loadings were prepared and characterized via BET, XRD, HRTEM-EDX, XPS and Raman, and parametrically tested under different CDRM conditions. Dispersion of Co particles was nonhomogeneous on all samples. For the sample with the highest Co/Ce ratio (10%Co-2%Ce/ZrO2), higher amount of lattice oxygen vacancies and lowest degree of ceria reduction were determined. Raman analysis showed that graphitic carbon coexisted with amorphous carbon on the surface of all spent samples. The extent of side reactions prevailed in determining selectivity. It was expressed that both Co-Ce synergistic interaction and synchronous contribution of Ce and ZrO2 were enhanced for the samples having lower Co/Ce ratio. It was confirmed that Ce is only responsible for oxygen transfer but not its formation.This work is financially supported by TUBITAK through project 111M144 . Financial support provided by Republic of Turkey Ministry of Development for laboratory infrastructure and postdoctoral scholarship (Dr. A. İ. Paksoy) through project 2016K121160 are greatly acknowledged

Efficient removal of methylene blue by photocatalytic degradation with TiO2 nanorod array thin films

TiO2 nanorod array thin films were synthesized on fluorine doped tin oxide (FTO) glass substrate by the hydrothermal method. The prepared TiO2 nanorod arrays were characterized by X-ray diffraction, scanning electron microscopy and UV-Vis diffuse reflectance spectroscopy. The effect of different synthesis conditions was investigated on the growth and photocatalytic activity of the samples. X-ray diffraction results show that the main phase of TiO2 is rutile and nanorod growth significantly depends on the synthesis conditions. TiO2 nanorod array thin films were used for the photocatalytic degradation of methylene blue in aqueous solution under UV irradiation (254 and 365 nm). The hydrothermal synthesis conditions of TiO2/FTO sample were determined for maximum photodegradation efficiency. Total degradation of 94 % was achieved under 254 nm and 69 % degradation was achieved under 365 nm with TiO2/FTO sample prepared with initial HCl:H2O = 1:1 ratio, 1.0 ml TiCl4 at 180 A degrees C for 2 h hydrothermal growth. The apparent reaction rate constant was calculated to be 0.0108 min(-1) under 254 nm and 0.0044 min(-1) under 365 nm