(583do) Effects of ZrO2 Particle Size and Structure On Cu-ZrO2 Interactions in Methanol Steam Reforming Catalysts

Methanol steam reforming over copper-based catalysts can be used to produce hydrogen at relatively low temperatures with carbon monoxide as a minor byproduct.  This reaction would thus have potential for use in automotive applications, such as on-board hydrogen generation in fuel cell vehicles, as it produces hydrogen with low CO concentrations and eliminates the need for hydrogen storage.  Furthermore, there is potential for a renewable energy pathway, if the methanol is produced from biomass.  However, for use in fuel cell applications, the CO concentration must be extremely low, while still maintaining a high methanol conversion.  Therefore, there is still room for improvement in copper-based steam reforming catalysts. 

Addition of ZrO₂ to Cu/ZnO/Al₂O₃ catalysts has been shown to improve copper-based methanol steam reforming catalysts, as both methanol conversion and selectivity to desired products (CO₂ and H₂) are improved.  The interaction between the Cu and the ZrO₂ is very important, and data indicates that monoclinic ZrO₂ results in favorable strong Cu-ZrO₂ interactions.  In particular, addition of monoclinic nanoparticle ZrO₂ significantly improves the activity of Cu/ZnO/Al₂O₃ catalysts.  To investigate the effects of zirconia only on the copper, Cu/ZrO₂ catalysts were prepared using different ZrO₂ nanoparticles (thus eliminating ZnO and Al₂O₃).  Zirconia nanoparticles with varying particle sizes were prepared with either a monoclinic or a tetragonal crystal structure.  The resulting catalysts were investigated in detail to determine how the ZrO₂ particle size and crystal structure affect the copper-zirconia interactions.