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

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') is 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 production from SR and ATR of ethanol and glycerol and in steam methane reforming (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 temperatures i.e. above 700°C. 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.