Reconstructing the Coordination Environment of Platinum Single-Atom Active Sites for Boosting Oxygen Reduction Reaction

Exploring highly efficient platinum single-atom (Pt-1) catalysts for oxygen reduction reaction (ORR) is desired to greatly reduce the catalysts costs of polymer electrolyte membrane (PEM) fuel cells. Herein, based on a nitrogen-doped active carbon (N-doped Black Pearl, NBP), an atomically dispersed Pt-based electrocatalyst is first prepared via a hydrothermal ethanol reduction method with Pt content of about 5 wt % (Pt-1/NBP), and it shows high selectivity for the two-electron oxygen reduction pathway. Through further high-temperature pyrolysis, the coordination environment of these isolated Pt atoms is reconstructed to form uniquely nitrogen-anchored platinum single-atom active sites (Pt-1@Pt/NBP) for a highly efficient four-electron oxygen reduction pathway. The obtained Pt-1@Pt/NBP catalyst presents excellent ORR performance and stability as well as fast ORR kinetics at a high potential region. As a cathode catalyst of a PEM fuel cell, Pt-1@Pt/NBP demonstrates 8.7 times higher mass activity than the commercial Pt/C at a cell voltage of 0.9 V.

Automated summary

Efficient platinum single-atom (Pt-1) catalysts are sought after for reducing the costs of polymer electrolyte membrane (PEM) fuel cells. In this study, a Pt-based electrocatalyst was prepared by hydrothermal ethanol reduction method with high selectivity for the oxygen reduction pathway. Further reconstruction of the coordination environment led to the formation of highly efficient platinum single-atom active sites for oxygen reduction. The obtained catalyst demonstrated excellent performance and stability, outperforming commercial Pt/C by 8.7 times in mass activity at a cell voltage of 0.9 V.