Localized electron density modulation in conjugated polymer nanosheets for boosting photocatalytic H2 evolution

A localized electron density modulation strategy is proposed to enhance the intrinsic surface catalytic proton reduction reaction by introducing dual pyridinic nitrogen (N) atoms into the polymer skeleton. Theoretical calculations suggest that the increased localized electron density at the N site can enhance the electron density of states around the Fermi level, which would lower the energy barrier to H adsorption and activation during the photocatalytic hydrogen evolution (PHE) process. Moreover, the increased localized electron density also contributes to accelerating the photo-induced charge separation and transportation. Resultingly, an apparent quantum yield of 35.5% of the newly developed conjugated polymer (termed as COP-PB-N2) can be achieved at a polymer concentration of 1 mg mL−1, which is the highest value achieved for conjugated microporous polymers to date. This work provides a new strategy through modulating the electronic properties of catalytically active sites for boosting the intrinsic photocatalytic performance.