Synergistic effect of platinum single atoms and nanoclusters for preferential oxidation of carbon monoxide in hydrogen-rich stream

Abstract

Despite the maximum atom-utilization efficiency and remarkable activity of single-atom catalysts, further improvement of catalytic activity can be obtained by the synergistic effect of single atoms and nanoclusters in some catalytic systems. Herein, CeFeOx-supported Pt single atoms coupling with subnanometric clusters (Pt1-Ptn) structures are developed via a facile strategy. They are applied as the highly efficient catalysts for the preferential oxidation of CO in H2-rich stream (CO-PROX), which achieve complete elimination of CO at low temperature of 50 °C, with a wide operating temperature window and extraordinary stability for over 500 h without noticeable deactivation. The exceptional performance is attributed to the synergistic effect of distinctive Pt1-Ptn structures, which couple the benefits of Pt single atoms and subnanometric clusters in a remarkable way. The disadvantages of single Pt species catalysts, such as sensibility to strong adsorption of CO or reduced lattice oxygen reactivity due to excessive coordination, can be well mitigated. The results of detailed characterizations and density functional theory calculations confirm that the unique structures possess moderate adsorption strength for CO and create abundant active interfacial oxygen species, because of the absence of bulk metallic Pt0 and appropriate coordination to lattice oxygen, which synergistically facilitate the catalytic performance.