Catalytic Activity, Stability, and Selectivity of Single Atom Pt on Nanoporous CuOx in the CO Oxidation and PROX Reactions

Currently, the removal of CO from automobile exhaust is accomplished by the oxidation of CO in catalytic converters. Noble metals catalysts are used on different supports but the problem is that they are rare and expensive⁽¹⁾. The goal is to have highly efficient catalysts for the reaction at low costs. The same reaction known as PROX (Preferential CO Oxidation) in a hydrogen- rich stream is important for PEMFC (Proton-exchange membrane fuel cells) which uses a Pt anode. The challenge is to attain a highly selective CO oxidation reaction to purify the inlet feed from CO as best as possible and prevent the poisoning of the Pt anode⁽²⁾. This project shows that successfully synthesized nano-porous (np) Cu by the sacrificial support method⁽³⁾, and Pt single atoms embedded in the surface of np-Cu by galvanic replacement is an excellent catalyst with high surface area and superior catalytic performance for both the dry CO oxidation reaction and the PROX reaction. In these oxidative reaction environments, the Cu will be oxidized to CuO_x. Pt/np-CuO_x with a Pt loading of 0.1 at.% has shown a better catalytic conversion over the np-CuO_x control catalyst at all conditions examined. It also showed good stability and maintained its activity during long-term steady- state experiments of 45 h. The Pt/np-CuO_x catalyst also showed high selectivity when used for the PROX reaction as the selectivity stayed at 100% at a temperature as high as 140 ^oC. This means that the single atom Pt /np-CuO_x catalyst used in this study has a good combination of high activity, stability and selectivity for the CO oxidation and PROX reaction under widely different tested conditions.

References

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