Enhancement of photocatalytic hydrogen evolution from dye–sensitized amide–functionalized carbon nanospheres by superior adsorption performance

Due to the high–efficiency and stable solar–to–hydrogen conversion efficiency, dye–sensitized photocatalytic hydrogen evolution is considered to be one of the ideal ways to solve today's energy and environmental problems. The coupling interaction between sensitization matrix and light–absorbing dye play an important role for the activity of the dye–sensitized photocatalytic hydrogen evolution. In this work, amide–functionalized carbon nanospheres as a new–style sensitization matrix is prepared by a low–cost and uncomplicated two–step liquid phase reactions. Because amide groups on the surface of carbon nanospheres add additional adsorption sites by introducing H–bonding and enhancing coupling interaction between the sensitization matrix and dye molecules, the adsorption capacity of amide–functionalized carbon nanospheres increase 6.7 times compared with bare carbon nanospheres. Based on the material excellent adsorption performance, the Eosin Y dye–sensitized amide–functionalized carbon nanospheres with Pt co–catalyst exhibits high–efficiency activity for H2 generation (607.4 μmol for testing 2 h), which is 14.3 and 6.4 times higher photocatalytic hydrogen evolution activity than Pt and carbon nanospheres with Pt assist. Moreover, the highest apparent quantum efficiency of photocatalyst can reach to 32.9% at 430 nm. The significantly improved photocatalytic hydrogen evolution performance of catalyst could be mainly ascribed to enhance amino groups adsorption active sites, which can fix the light–absorbing dyes on the surface of sensitization matrix and shorten the transmission distance of photogenerated charges.