Boosting surface charge transfer by aldehyde group grafted on loofah-sponge-like carbon nitride for visible light H2 evolution

Abstract

Although graphitic carbon nitride (g-C3N4) has broad prospects to resolve the energy crisis, but the rational design of catalyst with high photocatalytic efficiency remains a great challenge. Herein, the hollow porous loofah-sponge-like g-C3N4 incorporated with aldehyde group (LS-ACNx) was achieved via supramolecular self-assembly and thermal polymerization. The detailed characterization results indicated that the excellent performance was primarily attributed to the aldehyde group modification and hollow porous loofah-sponge-like structure. The aldehyde groups herein not only dramatically improve the interface charge transfer and suppress charge recombination, but also adjust the band structure and negative shift the conduction band position. The charge carries concentration of LS-ACN15 was 1.6 times higher relative to bulk g-C3N4 (CN). In addition, the hollow porous loofah-sponge-like morphology enhanced the specific surface area and light-harvesting ability. Benefiting from these, the obtained LS-ACN15 photocatalyst exhibited the superior photocatalytic H2 evolution performance of (10.5 ± 0.6) mmol g-1h−1, which was 96 times higher than that of the CN (0.109 mmol g-1h−1), and outperformed the majority of the previously g-C3N4-based photocatalysts. Particularly, the apparent quantum yield value was reached to be 16.8 % at 420 nm for LS-ACN15 photocatalyst. This work provides insights into constructing high performance catalysts by tuning energy band structure and charge transfer for energy and environment related field applications.