Structure evolution of Cu3Pd single-particles under CO2 hydrogenation

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-08, Vol.494, p.153208, Article 153208
• Main Authors: Xu, Changcheng, Han, Shaobo, Zhao, Qiao, Liu, Shuang, Liu, Wei, Li, Yong, Shen, Wenjie
• Format: Article
• Language: English
• Subjects: Charge transfer; Core-shell geometry; Cu3Pd particle; Restructuring; Reverse water–gas shift reaction; Surface segregation
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.153208

[Display omitted] •Structural evolution of CuPd single-particles depended on the reaction conditions.•H2-reduction at 873 K led to segregation of Pd atoms over Cu-enriched surface.•Pd atoms and electron-deficient Cu surface synergistically activated H2 and CO2.•O-containing species under CO2 hydrogenation induced Cu migration to form clusters. Encapsulating metal nanoparticles into a porous silica shell, forming a core–shell geometry, has been popularly applied to prevent the particles from sintering at the elevated temperatures and under reactive gases. However, structure evolution of the metal particles under reaction conditions is less known. Here, the dynamic behavior of Cu3Pd single-particles, confined by a permeable silica shell, during CO2 hydrogenation have been examined by microscopic and spectroscopic characterizations. It was found that H2-reduction of the bimetallic particle at 673 K led to the partial enrichment of Cu on the surface, while H2-treatment at 873 K resulted in the surface segregation of Pd owing to the stronger adsorption of H2 on Pd. When subjected to CO2 hydrogenation at 517–673 K, the enriched Pd surface atoms and the electron-deficient Cu atoms synergistically activated H2/CO2 molecules and promoted the activity for the reverse water–gas shift. However, the Cu atoms partially migrated onto the SiO2 shell and formed tiny Cu clusters, induced by the strong adsorption of O-containing reaction intermediates, forming a core@shell@satellite (CuPd@SiO2 @Cu) architecture.