A nanoreactor with Z-scheme FeS2/MoS2 heterojunctions encapsulated inside the carbon capsule: Insight on preparation method and enhanced performance in photo-Fenton reaction

Catalytic reaction confined in the nanoreactor could be accelerated by taking advantage of confinement effect. Photo-Fenton reaction has already been verified as an effective technique for pollutant degradation. Therefore, it was rational to infer that the degradation performance of photo-Fenton reaction inside the nanoreactor could be further improved. Nevertheless, how to construct a suitable nanoreactor to realize the aim was still a challenge. Herein, FeS2/MoS2@C nanoreactor with FeS2/MoS2 heterojunctions encapsulated inside the carbon capsule was prepared using Fe-MIL-101 as hard template via ions exchange, chelation competition induced polymerization, and calcination in sequence. In photo-Fenton reaction, photo-induced e(-) followed a Z-scheme transfer path, leading to the well-preserved redox capacity of separated e(-) and h(+). A large amount of reactive species were generated inside the capsule, and their contributions followed the order: (OH)-O-center dot > h(+) > O-1(2) >O- center dot(2)-. The complex catalytic mechanism was disclosed via tracing the source of reactive species. Furthermore, to better illustrate the confinement effect, the broken-FeS2/MoS2@C was prepared as a reference. The accelerated degradation rate, better visible-light harvest, enhanced photothermal effect, and higher yield of self-produced O-2 inside the integrated capsule were disclosed. This work illustrates the advantage of nanoreactor, and provides a new vision to improve the degradation performance in photo-Fenton reaction.

Automated summary

Catalytic reactions confined in nanoreactors can be accelerated by utilizing the confinement effect. In this study, a FeS2/MoS2@C nanoreactor with FeS2/MoS2 heterojunctions encapsulated inside a carbon capsule was prepared. The nanoreactor showed improved degradation performance in photo-Fenton reactions, and the catalytic mechanism and advantages of the nanoreactor were revealed.