Hydrogen production from simple alkanes and oxygenated hydrocarbons over ceria–zirconia supported catalysts: Review

Abstract

The use of ceria-zirconia based catalysts in hydrogen production from simple alkanes and oxygenated hydrocarbons for the processes of steam reforming (SR), autothermal reforming ('ATR'), catalytic partial oxidation ('CPO'), and dry reforming ('DR') are reviewed in this paper. Along with preparation methods, the effects of operating conditions like molar steam to carbon ratio, oxygen to carbon ratio, and temperature on the performance of hydrogen production from methane, acetic acid, ethanol, and glycerol were examined. SR and ATR of these feedstocks over ceria-zirconia supports have been widely investigated. In comparison the utilization of these supports in the CPO and DR processes has been investigated mainly for methane as compared to oxygenated hydrocarbons. Ce-rich supports were reported to be effective in hydrogen from SR and ATR of ethanol and glycerol and in SMR in the 'low' temperature range (500-600 °C), whereas zirconium-rich supports exhibited higher catalytic activity in the 'high' temperature range (700-800 °C). In the case of DR, Ce-rich supports were effective at high temperature. The methods of preparation of the supports/catalyst are shown to affect the surface area (catalyst/support), crystallite size of (active metal/support), reducibility and dispersion of the active metal, thus affecting performance of the catalyst.

Recent advances on the utilization of layered double hydroxides (LDHs) and related heterogeneous catalysts in a lignocellulosic-feedstock biorefinery scheme

“…153 The fuel, in this case ethanol, is reacted with steam at high temperatures in order to produce hydrogen-rich gas which, for example, can be used in fuel cell applications. The overall ethanol steam reforming reaction is represented by eqn (1) and (2).…”

“…This reaction is strongly endothermic and the reactor designs are typically limited by heat transfer, rather than by the reaction kinetics. 153,154 An alternative way of supplying heat to the reactor is to add oxygen or air to the feedstock. This oxygen will partially oxidize a fraction of the ethanol which is, for oxygen to ethanol molar ratios larger than 0.5, an exothermic reaction 155 (as represented in eqn (3) and (4)).…”

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

“…Due to its unique properties, zirconia acts as a heterogeneous support and a catalyst component in multiple important processes for obtaining sustainable chemicals, as has been highlighted in the recent reviews and reports. [17,21,4,26,25,11,37] Moreover, zirconia finds its applications in, for instance, solid oxide fuel cells [32] and electrochemical sensors. [22] Zirconia exists in several polymorphic modifications, among which monoclinic (m), tetragonal (t), and cubic (c) are the most common examples.…”

Effect of preparation procedure on the formation of nanostructured ceria–zirconia mixed oxide catalysts for ethyl acetate oxidation: Homogeneous precipitation with urea vs template-assisted hydrothermal synthesis

“…Ceria doping with zirconia improves essentially its thermal stability and catalytic efficiency [3,4,9,[13][14][15], which provokes its application in the three way catalyst formulations, solid oxides fuel cells and water splitting devices. Many studies emphasize the relationship between the catalytic activity and defect structure of these oxides [8,[16][17][18][19][20][21][22][23][24][25][26][27]. Suguira et al [28] attributed the enhanced OSC of CeO 2 -ZrO 2 mixed oxides to the formation of k-CeZrO 4 phase, where Ce 4+ and Zr 4+ ions are regularly arranged.…”