Single gold atoms stabilized on nanoscale metal oxide supports are catalytic active centers for various reactions

Key recent findings that demonstrate that single-gold atom sites stabilized on various oxide supports by -O bonds are the unique catalytic sites for a number of reactions, including the water-gas shift reaction, methanol partial oxidation and steam reforming reactions, and the selective dehydrogenation of ethanol are summarized herein. Atomic dispersion of gold on various metal oxides was followed with aberration-corrected high angle annular dark field/scanning transmission microscopy imaging and x-ray absorption spectroscopy (XANES/EXAFS). Gold nanoparticles and subnanometer clusters are active only through their interfacial atoms directly interacting with the support, hence if present, they entail precious metal waste. From a design perspective, the important feature in these supported catalysts is the creation of many single-site gold species anchored on the oxide support to maximize activity. Atomic gold-centered catalyst designs afford 100% atom efficiency, and more importantly, have distinct product selectivity, different from that of extended metal surfaces. Novel experimental synthesis methods of atomically dispersed Au catalysts are discussed, which pave the way for the efficient use of precious metals, broadening the application of properly designed gold and other precious metals (Pt, Pd) to different reactions in energy conversion and green chemicals production. (c) 2015 American Institute of Chemical Engineers AIChE J, 62: 429-439, 2016