Efficient “Click”‐Dendrimer‐Supported Synergistic Bimetallic Nanocatalysis for Hydrogen Evolution by Sodium Borohydride Hydrolysis

Abstract

Hydrogen is efficiently generated upon “click” dendrimer‐supported catalysis of NaBH4 hydrolysis by a series mono‐ and bimetallic nanoparticles (NPs) of the late transition metals. Among the monometallic NPs, PtNPs show the best performances, Co being the best first‐raw transition metal. A remarkable synergy between Pt and Co in Pt/CoNP@dendrimer is also disclosed, compared with various other bimetallic NP catalysts, achieving a TOF of 303\u2005molH2\u2009⋅\u2009molcatal.−1\u2009⋅\u2009min−1 when the ratio of Pt to Co is 1\u2009:\u20091. In the presence of NaOH, the catalytic activity is boosted for all monometallic NPs except PtNPs, but NaOH exerted a negative influence on the bimetallic NP catalysts. The kinetic studies with the catalyst Pt1Co1NP@dendrimer involve in particular a primary kinetic isotope effect kD/kH=3.41 obtained for the hydrolysis reaction with D2O, suggesting that O−H bond cleavage of water is involved in the rate‐determining step, and an overall reaction mechanism is proposed.