Selective and stable Au-Cu bimetallic catalyst for CO-PROX
Feng Hong, Guanjian Cheng, Weihao Hu, Shengyang Wang, Qike Jiang, Junhong Fu, Botao Qiao, Jiahui Huang
Abstract
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.