Using synchrotron-based spectroscopy techniques and advanced electron microscopy, the researchers determined that isolated gold ions most effectively convert acetylene, a gas derived from coal, to the VCM molecules that can be subsequently linked to form PVC.
Their discovery comes amid efforts to replace the conventional method of acetylene conversion, which uses a volatile and potentially toxic mercury-containing catalyst, with a more stable, non-polluting method that employs a carbon-supported gold catalyst.
The group examined the catalysts before and after use in Lehigh’s JEOL JEM-ARM200CF scanning transmission electron microscope (STEM), one of the most powerful instruments of its kind, allowing imaging and chemical analysis of materials at the atomic level.
The findings were reported in Science magazine in an article titled “Identification of single-site gold catalysis in acetylene hydrochlorination.” The article’s lead author is Grazia Malta of the Cardiff Catalysis Institute at Cardiff University in the UK who was supervised by Graham J. Hutchings, the Institute’s director. Kiely is co-director of the Cardiff Catalysis Institute.
Photo: STEM-HAADF image of the Au/C catalyst in the unused state.