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

Gold-based catalysts are promising in CO preferential oxidation (CO-PROX) reaction in H₂-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 H₂ 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 °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 H₂, both of which are helpful in inhibiting the competition of H₂ oxidation thus widening the temperature window for CO total conversion.