Cheng Han-Wen, Li Jing, Shan Shiyao, Lv Xiaowei, Chen Guanyu, Madiou Merry, Dinh Dong, Mousavi Seyed Danial, Wu Zhi-Peng, Wang Shan, Maswadeh Yazan, Petkov Valeri, Lu Susan, Pei Ke, You Wenbin, Che Renchao, Zhong Chuan-Jian
Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Materials Science, Academy for Engineering & Technology, Fudan University, Shanghai, 200438, China.
Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA.
Angew Chem Int Ed Engl. 2025 Aug 4;64(32):e202508735. doi: 10.1002/anie.202508735. Epub 2025 Jun 16.
The ability to control phase structures and surface sites of ultrasmall alloy nanoparticles under reaction conditions is essential for preparing catalysts by design. This is, however, challenging due to limited understanding of the atomic-scale phases and their correlation with the ensemble-averaged structures and activities of catalysts during catalytic reactions. We reveal here a dynamic structural stability of alumina-supported ultrasmall and equiatomic copper-gold alloy nanoparticles under reaction conditions as a model system in the in situ/operando study. In situ atomic-scale morphological tracking under oxygen reveals temperature-dependent dynamic crystalline-amorphous dual-phase structures, showing dynamic stability over an elevated temperature range. This atomic-scale dynamic phase stability coincides with a "conversion plateau" observed for carbon monoxide oxidation on the catalyst. It is substantiated by the stable lattice ordering/disordering structures and surface sites with oscillatory characteristics shown by operando ensemble-average structural tracking of the catalyst during the oxidation reaction. The understanding of the atomic-scale dynamic phase structures in correlation with the ensemble-average dynamic ordering/disordering phase structures and surface sites provides fresh insights into the unique synergy of the supported alloy nanoparticles. This understanding has implications for the design and structural tuning of active and stable ultrasmall alloy catalysts under elevated temperatures.
在反应条件下控制超小合金纳米颗粒的相结构和表面位点的能力对于通过设计制备催化剂至关重要。然而，由于对原子尺度的相及其在催化反应过程中与催化剂的系综平均结构和活性之间的相关性了解有限，这具有挑战性。我们在此揭示了在原位/操作条件研究中，作为模型系统的氧化铝负载的超小等原子铜金合金纳米颗粒在反应条件下的动态结构稳定性。在氧气存在下的原位原子尺度形态跟踪揭示了温度依赖性的动态晶态-非晶态双相结构，在升高的温度范围内显示出动态稳定性。这种原子尺度的动态相稳定性与在该催化剂上观察到的一氧化碳氧化的“转化平台”相吻合。这通过氧化反应过程中催化剂的操作系综平均结构跟踪所显示的具有振荡特征的稳定晶格有序/无序结构和表面位点得到证实。对原子尺度动态相结构与系综平均动态有序/无序相结构和表面位点相关性的理解为负载型合金纳米颗粒的独特协同作用提供了新的见解。这种理解对高温下活性和稳定的超小合金催化剂的设计和结构调整具有启示意义。
