Inhibition of hydrogen and oxygen recombination over amide–functionalized graphene and the enhancement of photocatalytic hydrogen generation in dye–sensitized AF–RGO/Pt photocatalyst dispersion

Abstract Photocatalytic hydrogen evolution (PHE) is a promising way to generate hydrogen driven by solar light. Noble metallic Pt is usually used as a co–catalyst to catalyze this reaction. However, Pt can also act as an active center for H 2 and O 2 recombination reverse reaction, which results in the low photocatalytic efficiency for H 2 generation. Herein, the H 2 and O 2 recombination can remarkably be inhibited by incorporating amide–functionalized groups onto graphene surface and edge, which act as the oxygen adsorbent site and reduce migration of O 2 molecules in the dye–sensitized PHE system. Theoretical studies verify that the adsorption energy of oxygen change remarkable due to orbital hybridization by N 2p in amide group with O 2p in O 2 molecule, leading to redistribution the electron structure of graphene, and change of electrical properties of sensitized matrix. By amide–functionalized graphene (AF–RGO), we achieved high H 2 evolution activity over AF–RGO/Pt nanohybrid catalyst under visible light irradiation. The quantum efficiency of AF–RGO/Pt (AF–RGO prepared at 140 °C) achieved 36.4% at 430 nm. This superior photocatalytic performance can be attributed to the repression of H 2 and O 2 recombination and the synergy of electrical properties. This work is helpful to design high active catalyst for solar hydrogen generation.