Understanding preparation variables in the synthesis of Au/Al2O3 using EXAFS and electron microscopy

The catalytic performance of Au/Al2O3 catalyst is highly sensitive to preparation procedure. EXAFS and TEM characterization of key steps in the preparation in conjunction with activity measurements result in deeper insights into precautions needed and the complex manner residual chloride impacts catalytic activity. Chloride affects the morphological (Au particle size), chemical (reducibility) as well as the catalytic (poisoning) properties of Au. Alternate preparation procedures to the conventional calcination of a catalyst prepared with deposition-precipitation at neutral pH were explored to increase Au loadings. It was found that low temperature H2 reduction of a catalyst prepared at low pH but washed with NaOH is an effective preparation method.