Tuning Amorphous-Crystalline Catalytic Interfaces by Mechanochemistry: Cu-Based Metallic Glasses Coupled with Ceria...

Amorphous metallic alloys, with their liquid-like atomic-scale structure, are promising candidates for developing unprecedented heterogeneous catalysts due to their non-equilibrium, highly disordered state. This study explores the combination of copper-based metallic glasses with crystalline ceria as catalysts for CO oxidation and preferential CO oxidation. The amorphous/crystalline interfaces are synthesized mechanochemically, offering a cost-effective alternative to the use of precious metals while maintaining high catalytic activity. Key parameters of the ball milling process are optimized, namely milling time and frequency, to enhance the interaction between the disordered metal and crystalline ceria, and the new catalysts are thoroughly characterized using ex situ techniques (XRD, DSC, HAADF-STEM-EDX, H₂-TPR, Raman spectroscopy, and XPS), and under operando conditions (XAFS and NEXAFS). These analyses reveal that the amorphous/crystalline architectures play a crucial role in catalytic performance. The results show that combining amorphous Cu-based metallic glasses with crystalline CeO₂ delivers remarkable catalytic activity in preferential CO oxidation (T₅₀ = 115 °C; 43.1 ± 0.4 mol CO₂ min^-1 g_catalyst ^-1), pointing to a sustainable and efficient design strategy of catalysts. This approach reduces reliance on noble metals while leveraging the synergy between structural disorder and crystallinity, thereby opening new directions for next-generation catalyst development.