In situ Stabilization of Au and Co Nanoparticles in a Redox-Active Conjugated Microporous Polymer Matrix: Facile Heterogeneous Catalysis and Electrocatalytic Oxygen Reduction Reaction Activity

We report a novel in situ method for synthesis of metal nanoparticles (NPs)-CMP (conjugated microporous polymer) composites based on a redox-active, donor-acceptor CMP, tris-(4-aminophenyl)amine (TPA)-perylenediimide (PDI). The TPA-PDI CMP, comprising triphenylamine as an electron donor and PDI as an acceptor, showed stable charge-separated state and semiconducting behavior. Further, TPA-PDI CMP has been exploited for in situ stabilization of metal (Au and Co) NPs, and two novel nanocomposites (Au@TPA-PDI and Co@TPA-PDI) were prepared. The catalytic reduction of nitro aryls to amino aryls was studied using Au@TPA-PDI, which showed excellent yields and fast kinetics. The CMP itself was found to show good activity as a metal-free oxygen reduction reaction (ORR) electrocatalyst with an onset potential of 0.82 V. Stabilizing merely 2.56 wt % Co nanoparticles in the CMP matrix improved the electrochemical ORR activity of as-synthesized TPA-PDI immensely and showed an onset potential of 0.91 V, which has also been supported by density functional theory (DFT) calculations.