Facile fabrication of poly(amidoamine) (PAMAM) dendrimers-encapsulated Ag–Co bimetallic nanoparticles for highly efficient dehydrogenation of ammonia borane. (30th January 2016)

• Record Type: Journal Article
• Authors: Ke, Dandan; Li, Yuan; Wang, Jin; Zhang, Lu; Wang, Jidong; Zhao, Xin; Yang, Shuqin; Han, Shumin
• Is Part Of: International journal of hydrogen energy. Volume 41:Number 4(2016)
• Page Start: 2564
• Page End: 2574
• Publication Date: 2016-01-30
• Subjects: PAMAM dendrimers -- Ag–Co bimetallic nanoparticles -- Hydrolytic dehydrogenation -- Ammonia borane; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.11.142
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Multifunctional poly(amidoamine) (PAMAM) dendrimers-encapsulated Ag–Co bimetallic nanoparticles (Ag–Co/PAMAM NPs) have been prepared via a facile co-complexation chemical reduction method. By exploiting the well-defined dendritic spatial construction of PAMAM dendrimers as NPs support and capping ligand, the as-synthesized NPs show unconspicuous agglomeration and uniformly distribution with average diameter of 5 nm. The Ag–Co/PAMAM NPs show the composition-dependent catalytic activity in catalytic dehydrogenation of ammonia borane (AB), with NPs in 30 atom.% Ag exhibiting the superior activity and yielding an initial turnover frequency (TOF) as high as 15.84 molH2 ·min −1 ·molM −1 . Combined with the electro–transfer interaction between Ag and Co, the effective control of the NPs dispersibility and the electro-donating ability of PAMAM dendrimers with amounts of amide and amine groups facilitate the catalytic performances of Ag–Co/PAMAM catalyst on the hydrolysis of AB. The work also includes the kinetic studies on zero-order with respect to substrate concentration and first-order reaction with respect to catalyst concentration, as well as temperature effect to determine the apparent activation energy of the reaction (Ea = 35.66 kJ mol −1 ). Furthermore, the reusability tests reveal Ag–Co/PAMAM NPs still show good catalytic activity and magnetically reusability in successive runs, which make these dendrimers-stabilized bimetallic nanoparticles promising heterogeneous catalysts in practical application. Graphical abstract: Highlights: A novel PAMAM dendrimers-encapsulated Ag–Co catalyst is prepared. Poly(amidoamine) dendrimers benefit AgCo NPs formation and dispersibility. Catalytic activity of AgCo/PAMAM NPs is largely enhanced on AB hydrolytic reaction. Initial turnover frequency (TOF) value reaches to 15.84 molH2 ·min −1 ·molM −1 . Synergistic effect of PAMAM-encapsulated AgCo on AB hydrolysis reaction is studied.