Conjugated Polymer Donor-Molecular Acceptor Nanohybrids for Photocatalytic Hydrogen Evolution

A library of 237 organic binary/ternary nanohybrids consisting of conjugated polymers donors and both fullerene and non-fullerene molecular acceptors was prepared and screened for sacrificial photocatalytic hydrogen evolution. These donor-acceptor nanohybrids (DANHs) showed significantly enhanced hydrogen evolution rates compared with the parent donor or acceptor compounds. DANHs of a polycarbazole-based donor combined with a methanofullerene acceptor (PCDTBT/PC₆₀BM) showed a high hydrogen evolution rate of 105.2 mmol g^-1 h^-1 under visible light (λ > 420 nm). This DANH photocatalyst produced 5.9 times more hydrogen than a sulfone-containing polymer (P10) under the same conditions, which is one of the most efficient organic photocatalysts reported so far. An apparent quantum yield of hydrogen evolution of 3.0 % at 595 nm was measured for this DANH. The photocatalytic activity of the DANHs, which in optimized cases reached 179.0 mmol g^-1 h^-1, is attributed to efficient charge transfer at the polymer donor/molecular acceptor interface. We also show that ternary donor_A-donor_B-acceptor nanohybrids can give higher activities than binary donor-acceptor hybrids in some cases.