Influence of Processing Conditions on Structures of 3D Ordered Macroporous Metals Prepared by Colloidal Crystal Templating

• DOI: 10.1021/cm0105716
• Publication Date: 2002-07-26T04:50:13Z
• Authors: Hongwei Yan; Christopher F. Bl...; Justin C. Lytle; C. Barry Carter; William H. Smyrl; Andreas Stein
• Keywords: Colloidal crystal; Carbon fibers; Polystyrene; Template method pattern

This paper presents general methods of preparing three-dimensionally ordered macroporous (3DOM) metals or alloys via templated precipitation and subsequent chemical conversion metal salts (acetates, oxalates) within colloidal crystals poly(methyl methacrylate) (PMMA) polystyrene (PS) spheres. Three approaches are given to prepare 3DOM metallic Ni, Co, Fe the alloy Ni1-xCox: (1) calcination oxalate/template composite in a nitrogen atmosphere, (2) formation oxide followed by reduction hydrogen, (3) direct hydrogen. The products obtained these routes differ size grains that compose wall skeletons, surface areas, compositions. Method 1 leads very small high areas but incomplete removal carbon with graphitic layers surrounding grains. 2, as two-step process, relatively large grains, smaller carbon-free products. 3 strikes compromise properties, intermediate (<2%) amounts remaining carbon. synthetic details, discusses effects template choice (PMMA vs PS), compares structural features alloys, using results XRD, TGA, SEM, TEM, adsorption data, analysis.