In2S3/g-C3N4/CoZnAl-LDH composites with the lamellar dual S-scheme heterostructure and its enhanced photocatalytic performance

Abstract

The construction of heterostructures is considered as an excellent strategy to achieve efficient charge separation and enhance photocatalytic activity. In this paper, CoZnAl-LDH was first prepared by a temperature-programmed hydrothermal method. Then g-C3N4/CoZnAl-LDH composite was synthesized by loading g-C3N4 in situ, followed by supporting In2S3 on the surface of composite g-C3N4/CoZnAl-LDH. Finally, a novel dual S-scheme lamellar photocatalyst In2S3/g-C3N4/CoZnAl-LDH with ternary heterojunction was prepared. The crystal structure, morphology, composition and surface physicochemical properties of as-prepared photocatalysts were characterized by various testing methods. The results show that the lamellar In2S3/g-C3N4/CoZnAl-LDH composite mainly presents the characteristic structure of CoZnAl-LDH hydrotalcite compounds, and In2S3 and g-C3N4 are attached to the surface of CoZnAl-LDH. Compared with CoZnAl-LDH, the light absorption range of In2S3/g-C3N4/CoZnAl-LDH composite material is obviously broadened, and the specific surface area is increased. The results of multi-mode photocatalytic degradation of pollutants show that the photocatalytic degradation activity of In2S3/g-C3N4/CoZnAl-LDH composite with In2S3 loading weight ratio of 40% is significantly higher than that of a single CoZnAl-LDH or g-C3N4/CoZnAl-LDH composite material. In addition, the composite exhibits enhanced photocatalytic hydrogen production capacity (404.78 μmol/g hydrogen production in 8 h, which is more than 6 times that of the monomer CoZnAl-LDH). Moreover, the photocatalytic activity remains stable after 3 cycles of experiments. The introduction of g-C3N4 and In2S3 on the CoZnAl-LDH matrix to form a dual S-scheme heterostructure is one of the main reasons for the enhanced photocatalytic activity.