Investigation of structural changes in mixed-metal catalytic aerogels at elevated temperatures

Aerogels possess physical properties that make them interesting in research for better catalytic converters. They have a low density as well as a high surface area and porosity. Catalytic converters currently employ precious metals such as platinum, palladium, and rhodium to catalyze the oxidation of carbon monoxide (CO) and unburned hydrocarbons (HCs) and reduce nitrous oxides (NO_x). These precious metals are expensive and in low abundance in the earth's crust. Aerogels containing catalytic metals such as copper or nickel could be a cheaper alternative to the modern solution. Past work on copper-, nickel-, and cobalt-containing silica and alumina aerogels have shown promise for replacing current catalytic converters. The aerogels are fabricated using a sol-gel method and then ethanol excreted out using the rapid supercritical extraction (RSCE) method, patented by Union College. After fabrication, the aerogels underwent heat treatment to 800 ?C, above the highest temperature at which a catalytic convertor routinely performs. Through the use of powder x-ray diffraction (XRD) with thermal control, the aerogels were tested to determine their morphology before and after heat treatment as well as at elevated temperatures. The XRD patterns of the aerogels showed structural changes as heat treatment occurred. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to show dispersion of impregnated metal as well as nano crystalline structures within the aerogel.

Union College Schaffer Library Digital Projects

Union College Schaffer Library Special Collections, 807 Union St., Schenectady, NY 12308; 518-388-6620; https://www.union.edu/schaffer-library