Rational construction of visible-light-driven MIL-88A(Fe)@PMo12 heterojunction with S-scheme electron transfer pathway to activate peroxymonosulfate for degradation of organic pollutants

Coupling of photocatalysis and persulfate oxidation is a promising approach to remove refractory organic pollutants. In 2022, there are about 30 publications on this topic, and the frequency of citations for related articles has reached 1,100. But the rational design and engineering of a desirable photocatalyst is still a great challenge. Herein, a S-scheme heterojunction photocatalyst was prepared by incorporation of Keggin phosphomolybdic acid (PMo12) into MIL-88A(Fe) through a one-step hydrothermal method. The prepared catalyst was characterized by several techniques, and used as visible-light-driven photocatalyst to activate peroxymonosulfate for the degradation of pollutants. The optimal photocatalyst (MIL-88A(Fe)@PMo12-30) displayed the outstanding catalytic activity and good stability. In MIL-88A(Fe)@PMo12-30 system, the degradation rate of AR18 could be increased by 20.55 times compared pristine MIL-88A(Fe). PMS concentration, catalyst dosage, initial pH value, and dye concentration influenced AR18 degradation. The scavenging experiments and EPR analysis disclosed that reactive species (RSs), including SO4−, OH, O2−, h+, and 1O2 were generated. Basis on the band structure, reactive species, PL and electrochemical analysis, the enhanced photocatalytic performance of MIL-88A(Fe)@PMo12-30 was mainly ascribed to the intimate contact of both component and unusual S-scheme electron transfer path. This work may open new horizons to construct efficient POMOFs hybrid photocatalysts.