Insight for FeS2/MoS2 @SiO2 nanoreactor with spatial separation of H2O2 activation sites and pollutant adsorption sites: Enhanced H2O2 activation efficiency and pollutant degradation performance in Fenton reaction

In Fenton reaction, catalyst surface were served as pollutant adsorption sites and H2O2 active sites simultaneously, and this was not beneficial for full exploitation of catalyst surface. Herein, FeS2/MoS2 @SiO2 nanoreactor with FeS2/MoS2 nanoparticles encapsulated inside the mesoporous SiO2 capsule were prepared, where pollutants were mainly adsorbed on mesoporous SiO2 shell, and H2O2 were activated on FeS2/MoS2 surface. In Fenton reaction, the H2O2 activation efficiency of FeS2/MoS2 @SiO2 were 3.1 times higher than that of FeS2/MoS2. Mechanism study indicated a large amount of •OH were generated inside the capsule, and this was favorable for their conversion to 1O2 and •O2-, whose lifetimes were much longer than that of •OH. Owing to the far transmission distance of 1O2 and •O2-, the opportunity for their attack on the pollutants enriched on mesoporous SiO2 shell was increased, leading to an enhanced H2O2 activation efficiency and tetracycline degradation performance. Moreover, the protective functions of mesoporous SiO2 shell were also exploited. The metal leaching was reduced, the anti-interference property toward anions and large organic molecules were enhanced, and the stability was improved. The results of this research explored the advantages of nanoreactor and provided a new insight to improve H2O2 activation efficiency in Fenton reaction. [Display omitted] •Adsorption and activation sites are separated, leading to their maximum exploitation.•TC are enriched on SiO2 shell, adsorption of FeS2/MoS2 @SiO2 is higher than FeS2/MoS2.•28.1% of H2O2 is activated to ROSs in FeS2/MoS2 @SiO2, 3.1 times higher than FeS2/MoS2.•O2– and 1O2 came from •OH are the main ROSs due to long life and transfer distance.•Anti-interference property and stability are good due to protection from SiO2 shell.