Autor: |
Smith PJ; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK., Kondrat SA; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK., Carter JH; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK., Chater PA; Diamond Light Source Didcot OX11 0DE UK., Bartley JK; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK., Taylor SH; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK., Spencer MS; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK., Hutchings GJ; Cardiff Catalysis Institute, School of Chemistry Cardiff University Main Building, Park Place Cardiff CF10 3AT UK. |
Abstrakt: |
A series of copper-zinc acetate and zincian georgeite precursors have been produced by supercritical CO 2 antisolvent (SAS) precipitation as precursors to Cu/ZnO catalysts for the water gas shift (WGS) reaction. The amorphous materials were prepared by varying the water/ethanol volumetric ratio in the initial metal acetate solutions. Water addition promoted georgeite formation at the expense of mixed metal acetates, which are formed in the absence of the water co-solvent. Optimum SAS precipitation occurs without water to give high surface areas, whereas high water content gives inferior surface areas and copper-zinc segregation. Calcination of the acetates is exothermic, producing a mixture of metal oxides with high crystallinity. However, thermal decomposition of zincian georgeite resulted in highly dispersed CuO and ZnO crystallites with poor structural order. The georgeite-derived catalysts give superior WGS performance to the acetate-derived catalysts, which is attributed to enhanced copper-zinc interactions that originate from the precursor. |