Nitrogen-doping microporous carbon nanosheets with superior adsorption and conductivity for enhancement photocatalytic water reduction

Dye-sensitized photocatalytic water reduction hydrogen evolution (DS-PWRHE) with efficient spectral absorption and stable photoelectric conversion efficiency shows considerable application prospects for the conversion and storage of solar energy. The coupling interaction and charge migration between light-absorbing dye and sensitization matrix are crucial factors for improving the activities of DS-PWRHE. Herein, nitrogen-doping microporous carbon nanosheets (N-MCNs) as new-style sensitization matrix is synthesized by direct calcination method using ethylene diamine tetraacetic acid tetrasodium as raw material. Theoretical simulations find that N-MCNs with superior thermodynamic stability can optimize the charge distribution by implanting N heteroatoms in the limited carbon framework. The structural and performance tests indicate that the conductivity and adsorption properties of N-MCNs is greatly improved since a large of N heteroatoms not only act as boosters for carrier migration, but also are used as anchors for dye molecules. These superior physicochemical properties of N-MCNs as multifunctional sensitized matrix provide the prerequisite for H2 generation occurring in DSPWRHE system due to shorten transmission distance of photogenerated charges. The high-activity NMCNs@Pt nanohybrid catalyst is prepared by in-situ photo-deposition method base on advantages of N-MCNs. Typically, in the neutral triethanolamine aqueous solution with Eosin Y dye-sensitized photocatalytic system, NMCNs@Pt displays 685.8 mu mol of H2 for testing 120 min under visible light irradiation and 34.2 % of apparent quantum efficiency at 430 nm excitation.