Donut Assembly of Nanoparticles with High Catalytic Efficiency for Hydrogen Gas Generation from Ammonia Borane

Polymer-supported transition metal nano particles usually exhibited low catalytic efficiency due to the long diffusion length for the reactants to reach the catalytic center. Herein, we used cyclic polymers to construct donut-like assembly with two cyclic macromolecules sandwiching a layer of metal NPs. Doping Rh into the nano particles led to extremely active catalysts for ammonia borane decomposition with a high TOF of 780 min⁻¹. We attributed the high efficiency to the reduced diffusion length in this special assembly. Light-promoted effect was also demonstrated with TOF further elevated to 980 min⁻¹. The modular nature of this design also permitted subsequent structural modification to achieve high stability with TON reaching over 2×10⁶.