Cu3Pt1 alloys confined by penta-coordinate Al3+ on Al2O3 realize CO oxidation at room temperature

Abstract

CO is a ubiquitous air pollutant, frequently encountered in the fields of automotive exhaust purification, especial in the cold-start-emission stage. Pt based catalysts are widely used to purify CO into CO₂ owing to their exceptional performance. But they can be few excited to exhibit reasonable catalytic activity due to the low temperature at the cold-start-emission stage. In exhaust gas purification catalysts used by fossil fuel-based vehicles, Al₂O₃ is used frequently. But there are rarely reports of Pt loaded Al₂O₃ catalysts achieving feasible activity of CO oxidation at room temperature. Herein, we prepared Cu_xPt_y alloy/Al₂O₃ catalysts (with high penta-coordinated Al³⁺ (Al_V)), Al_V centers as binding sites for Cu₃Pt₁ alloys on Al₂O₃ enable the high dispersion and stability of Cu₃Pt₁ alloy. The adsorption capacity of O₂ and CO molecules on Cu₃Pt₁ surface are stronger than the case on Pt surface, which may make O₂ and CO molecules more easily activated, making the CO oxidation reaction easier. In addition, the desorption of CO₂ from Cu_xPt_y surface is easier compared to that on Pt surface, increasing the frequency of use of active sites there. Therefore, this Cu₃Pt₁/Al₂O₃ catalyst exhibits 100 % conversion of CO with a GHSV of 6×10³ mL·g⁻¹_cat·h⁻¹ at room temperature. This work provides a feasible guideline for the design and synthesis of Pt loaded Al₂O₃ catalysts toward room temperature CO oxidation.