(3-Aminopropyl)trimethoxysilane-Assisted Co-assembly to Monolithic Pd@SiO2/Al2O3/Al Catalysts for Low Concentration CH4 Combustion: Effect of Preparation Conditions

• Published in: Catalysis letters 2024-07, Vol.154 (7), p.3388-3401
• Main Authors: Zhang, Qiaofei, Liu, Miaomiao, Liu, Zhiming, Wang, Pengwei, Gao, Jianfei
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Catalysis; Catalysts; Chelation; Chemistry; Chemistry and Materials Science; Combustion; Core-shell structure; Coupling agents; Industrial Chemistry/Chemical Engineering; Low temperature; Methane; Organometallic Chemistry; Oxidation; Palladium; Physical Chemistry; Reagents; Silicon dioxide; Thermal decomposition; Thermal stability
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-023-04485-x

Herein, an affordable strategy was developed to form Pd@SiO 2 nanostructure assembled onto monolithic AlOOH/Al nanoarrays from nano- to macro-scale by a one-step reaction process. (3-Aminopropyl)trimethoxysilane (APTMS) was employed as a dual-role reagent for the bidirectional bridging between Pd 2+ and AlOOH/Al, as well as the formation of SiO 2 matrix and mesopores. The effects of one-step organization conditions on the preparation process, catalyst structure, and catalytic performance were all studied. High hydroxyl contents in Al-based nanoarrays promoted the silanization reaction of APTMS deposition, resulting in a well-formed SiO 2 shell and abundant mesopores during the thermal decomposition of APTMS. APTMS amount was not only related to SiO 2 loading and encapsulation effect of the core–shell structure, but also affected Pd accessibility. Such proposed APTMS-assisted protocol for the in-situ organization of monolithic Pd@SiO 2 catalysts can effectively prevent the growth and aggregation of Pd NPs, thereby favoring low-temperature activity and stability for CH 4 combustion. Graphical Abstract Monolithic Pd@SiO 2 catalysts supported on AlOOH/Al nanoarrays were successfully fabricated from nano- to macro-scale in one step for improved thermal stability of CH 4 combustion. The cost-effective coupling agent (APTMS) acted as the bidirectional bridging between –NH 2 of APTMS and Pd 2+ through preferential chelation, as well as a silanization reaction between methoxy groups of APTMS and surface –OH groups on AlOOH nanoarrays to form Al–O–Si bonds.