ZIF-8 derived N-doped carbon polyhedron as nonmetallic co-catalyst for photocatalytic hydrogen production

Loading co-catalyst with good conductivity is a common method to restrain carrier recombination and accelerate water splitting kinetics. However, commonly used metal-based co-catalysts faced with expensive price, resource shortage and environmental pollution problems. In this article, N-doped carbon polyhedron (NCP) is identified as a novel nonmetallic co-catalyst which is obtained by pyrolysis of a zeolitic imidazolate framework (ZIF-8). The composite NCP@CdS photocatalyst is prepared by hydrothermal method to synthesis NCP co-catalyst loaded CdS. Therein, the obtained NCP@CdS exhibites excellent photocatalytic performance. Under visible light irradiation (λ > 420 nm), the hydrogen generation rate of NCP@CdS is up to at 13.89 mmol g^-1h⁻¹, which is 8.3 times as that of CdS. In addition, NCP also achieves the positive effect of promoting photocatalytic hydrogen production under different sacrificial systems. It is demonstrated through a series of characterizations and analyses that N-doped graphitic carbon skeleton has played several positive roles, including promoting charge separation by providing electron transfer channels and serving abundant reactive sites with unique N-structure.