• Energy Research

The production of dimethyl ether (DME), renewable fuel, using dehydration of methanol over Co supported on kaolinite catalysts was investigated. In this study, kaolinite was modified by impregnation of the various percentage of Co (5%Co/KN, 10%Co/KN, and 15%Co/KN) to improve the activity of the catalyst. The prepared catalysts were characterized by nitrogen gas adsorption using the Brunauer–Emmett–Teller (BET) method, and the X-ray diffractometer (XRD). The thermogravimetric analysis (TGA) was used to analyze of coke formation on spent catalysts. The catalytic performances of catalysts were tested in a fixed-bed reactor at atmospheric pressure at the temperature range of 250–350 °C with a fixed weight hourly space velocity (WHSV) of 2.054 h−1. It was found that 5%Co/kaolinite showed the highest methanol conversion of 81.7% among the Co/KN catalysts; however, the DME selectivity was less than 80%. The presence of Co gave the less formation of coke on used catalysts indicating that the Co/KN catalyst had more stable than unmodified kaolinite. The 15%Co/KN is an active, selective, and durable catalyst for DME production at the temperature of 300 °C.

The photocatalytic reduction of carbon dioxide into hydrocarbon over bimetallic-loaded TiO2 supported on SiO2-Al2O3(Ni–Cu–TiO2/SiO2-Al2O3) catalyst was studied. The study also compared the performance of the catalyst with Degussa P25 (TiO2), prepared TiO2, SiO2-Al2O3 loaded with TiO2. The investigation of catalytic performance was carried out in a batch reactor under UV irradiation. All the samples were characterized by X-ray diffractometer (XRD), N2gas adsorption–desorption, and Ultraviolet–visible diffuse reflectance spectrometer (UV–Vis-DRS). The result showed SiO2-Al2O3loaded with Ni–Cu–TiO2yielded the highest production rate of methanol (405.08μmol/gcat) after 2 h of reaction under UV at room temperature and a pressure of 1 atm. The photocatalytic reduction rate over the bimetallic-loaded TiO2 supported on SiO2-Al2O3 catalysts was found to be approximately 2.4 times that over SiO2-Al2O3 loaded with TiO2. This can be explained by the presence of nickel and copper on the catalyst which reduced the energy bandgap of the catalyst and decreased the recombination of electron–hole pairs.