A new allotrope of carbon-graphdiyne, synthesis and application in photocatalytic hydrogen evolution with surface plasmon resonance enhancement

Abstract

Graphdiyne (GDY, g-C_nH_2n−2) is a new type of carbon material and is a promising material for efficient photocatalytic hydrogen evolution. In this work, the GDY was successfully synthesized using a unique method based on CuI as a template. The CuI had a catalytic effect, and it can deliver copper ions (Cu⁺) under pyridine conditions. In addition, eosin-Y (EY) sensitized GDY located with Au nanoparticles (NPs) (EY-GA-40) had the highest H₂ evolution activities achieved: 319.1 μmol after five hours under visible light irradiation, and this was 245.4 times higher than the value achieved with unmodified GDY, due to the dual electron injection (DEI) effect. The DEI effect meant that both the EY and the Au NPs could supply electrons for the GDY under illumination. The GDY had a strong ability to absorb the dye molecules, which enabled the excitation state electron of the EY to transfer to the surface of the GDY. The conduction band (CB) of the GDY is lower than the surface plasmon resonance (SPR) state of the Au NPs. Hence, the excited energetic electrons in the SPR state can be injected into the CB of GDY and thus they can participate in the hydrogen evolution reaction (HER) on the surface of GDY. Meanwhile, the LUMO potential of EY is more negative than the CB of the GDY, so the electrons can be easily injected into the CB of the GDY. Hence, the photocatalytic hydrogen evolution activity of the GDY showed a great improvement because of the DEI effect. This work not only provides a novel approach for the application of GDY but also contributes a new strategy for the modification of catalysts.