Steam reforming of ethanol on Ni–CeO2–ZrO2 catalysts: Effect of doping with copper, cobalt and calcium

Abstract

Steam reforming (SR) and oxidative steam reforming (OSR) of ethanol were investigated over undoped and Cu, Co and Ca doped Ni/CeO 2 -ZrO 2 catalyst in the temperature range of 400-650°C. The nickel loading was kept fixed at 30 wt.% and the loading of Cu and Co was varied from 2 to 10 wt% whereas the Ca loading was varied from 5 to 15 wt.%. The catalysts were characterized by various techniques, such as surface area, temperature programmed reduction, X-Ray diffraction and H 2 chemisorption. For Cu and Co doped catalyst, CuO and Co 3 O 4 phases were detected at high loading whereas for Ca doped catalyst, no separate phase of CaO was found. The reducibility and the metal support interactions were different for doped catalysts and varied with the amount and nature of dopants. The hydrogen uptake, nickel dispersion and nickel surface area was reduced with the metal loading and for the Co loaded catalysts the dispersion of Ni and nickel surface area was very low. For Cu and Ca doped catalysts, the activity was increased significantly and the main products were H 2 , CO, CH 4 and CO 2 . However, the Co doped catalysts showed poor activity and a relatively large amount of C 2 H 4 , C 2 H 6 , CH 3 CHO and CH 3 COCH 3 were obtained. For SR, the maximum enhancement in catalytic activity was obtained with in the order of NCu5. For Cu-Ni catalysts, CH 3 CHO decomposition and reforming reaction was faster than ethanol dehydrogenation reaction. Addition of Cu and Ca enhanced the water gas shift (WGS) and acetaldehyde reforming reactions, as a result the selectivity to CO 2 and H 2 were increased and the selectivity to CH 3 CHO was reduced significantly. The maximum hydrogen selectivity was obtained for Catalyst N (93.4%) at 650°C whereas nearly the same selectivity to hydrogen (89%) was obtained for NCa10 catalyst at 550°C. In OSR, the catalytic activity was in the order N > NCu5 > NCa15 > NCo5. In the presence of oxygen, oxidation of ethanol was appreciable together with ethanol dehydrogenation. For SR reaction, the highest hydrogen yield was obtained on the undoped catalyst at 600°C. However, with calcium doping the hydrogen yields are higher than the undoped catalyst in the temperature range of 400-550°C.

Effect of Microgravity on Synthesis of Nano Ceria

“…Moreover, the high thermal stability of ceria is attractive for reactions which are conducted at high temperatures [2]. Therefore, ceria has been extensively utilized in three-way catalysts [5][6][7] and fuel cells [8,9], as well as investigated for its activity in catalytic reactions such as CO oxidation [10,11], steam reforming [12][13][14][15][16][17], and water gas shift (WGS) [18,19].…”

Co–Ni Catalysts Derived from Hydrotalcite-Like Materials for Hydrogen Production by Ethanol Steam Reforming

“…Kelfin et al examined the influence of preparation methods on the behavior of Co-Ni/Al 2 O 3 catalysts in the steam reforming of propane [18]. However, there are only very limited investigations of the steam reforming of ethanol over Co-Ni bimetallic catalysts [16,19,20]. Besides working as catalysts, both Ni and Co have another interesting feature, functioning as an oxygen carrier facilitating chemical looping and autothermal reforming.…”

Steam Reforming of Glycerin Using Ni-based Catalysts Loaded on CaO–ZrO2 Solid Solution

“…In several literature reports, it has been indicated that CeO 2 is a better support material for Ni than MgO, Al 2 O 3 , and TiO 2 in the reforming of oxygen-containing substances [15,16,27,30] For the reduction of carbon formation, the addition of a small amount of CeO 2 to Ni(5 wt%)/CaOZrO 2 catalyst was examined. Figure 7 shows the effects of different preparation methods for CeO 2 -loaded catalysts on the performance of the reforming of glycerin at 600°C.…”

“…cations with one of these cations leads to a negative overall charge that is compensated for by an increased number of oxygen vacancies, in order to maintain electrical neutrality. Oxygen mobility is therefore enhanced, making it possible for stabilized ZrO 2 to be employed as a catalytic support in the reforming of hydrocarbons [24][25][26][27][28].…”