Selective and stable Au-Cu bimetallic catalyst for CO-PROX

Gold-based catalysts are promising in CO preferential oxidation (CO-PROX) reaction in H-2-rich stream on account of their high intrinsic activity for CO elimination even at ambient temperature. However, the decrease of CO conversion at elevated temperature due to the competition of H-2 oxidation, together with the low stability of gold nanoparticles, has posed a dear challenge. Herein, we report that Au-Cu bimetallic catalyst prepared by galvanic replacement method shows a wide temperature window for CO total conversion (30-100 degrees C) and very good catalyst stability without deactivation in a 200-h test. Detailed characterizations combined with density functional theory (DFT) calculation reveal that the synergistic effect of Au-Cu, the electron transfer from Au to Cu, leads to not only strengthened chemisorption of CO but also weakened dissociation of H-2, both of which are helpful in inhibiting the competition of H-2 oxidation thus widening the temperature window for CO total conversion.

Automated summary

Gold-based catalysts have shown promise for CO preferential oxidation (CO-PROX) reaction in H-2-rich streams due to their high intrinsic activity for CO elimination even at room temperature. However, the competition of H-2 oxidation and the low stability of gold nanoparticles have limited the CO conversion at elevated temperatures. In this study, a Au-Cu bimetallic catalyst prepared by galvanic replacement method was found to exhibit a wide temperature window for CO total conversion (30-100 degrees C) and excellent catalyst stability without deactivation during a 200-hour test. Detailed characterizations and density functional theory (DFT) calculations revealed that the synergistic effect of Au-Cu and the electron transfer from Au to Cu enhanced the chemisorption of CO and weakened the dissociation of H-2, inhibiting the competition of H-2 oxidation and widening the temperature window for CO total conversion.