A Review of Preparation Methods for Supported Metal Catalysts

To gauge the efficacy of the various methods to synthesize supported metal catalysts, over 1500 literature articles from the past 3 years have been surveyed. Platinum catalysts over silica (SiO2), alumina (Al2O3), titania (TiO2), and carbon (C) supports have been selected as examples. We include our work on the methods of strong electrostatic adsorption (SEA) and a newer version of it, charge-enhanced dry impregnation (CEDI). These methods are compared and contrasted to those most prevalent in the literature. SEA and CEDI yield ultra-small nanoparticles, usually less than 1.5 nm average particle size, and are simple and scalable, especially CEDI, which is a simple adaptation of common incipient wetness impregnation. These methods can be extended to the synthesis of supported bimetallic nanoparticles with equally efficacious results.