Highly Efficient Catalysis of Preferential Oxidation of CO in H2-Rich Stream by Gold Single-Atom Catalysts

Preferential oxidation of CO (PROX) in H 2 -rich stream is critical to the production of clean H 2 for the H 2 -based fuel cells, which provide clean and efficient energy conversion. Development of highly active and selective PROX catalysts is highly desirable but proved to be extremely challenging. Here we report that CeO 2 -supported Au single atoms (Au 1 /CeO 2 ) are highly active, selective, and extremely stable for PROX at the PEMFC working temperature (∼80 °C) with >99.5% CO conversion over a wide temperature window, 70–120 °C (or 50–100 °C, depending on the Au loading). The high CO conversion realized at high temperatures is attributed to the unique property of single-atom catalysts that is unable to dissociatively adsorb H 2 and thus has a low reactivity toward H 2 oxidation. This strategy is proven in general and can be extended to other oxide-supported Au atoms (e.g., Au 1 /FeO x ), which may open a new window for the efficient catalysis of the PROX reaction.