Core-shell bimetallic Fe-Co MOFs to activated peroxymonosulfate for efficient degradation of 2-chlorophenol

Based on two topologically distinct MOFs, the core-shell bimetallic MIL-101/ZIF-67(x) (M/Z(x)) were successfully prepared to activate the self-decomposition of peroxymonosulfate (PMS) for 2-chlorophenol (2-cp) degradation. The M/Z(x) not only inherited the merits of single-metal MOFs such as high surface area and pore volume, but also exhibited superior catalytic performance. In the M/Z(x)/PMS system, 90% of the 2-cp (100 mg/L) was removed within 10 min with a reaction rate of 0.241 min(-1). This observation was attributed to the synergistic catalysis of cobalt and iron active sites in M/Z(x), which greatly promoted the Co2+/Co3+ redox cycle, thereby enhancing the catalytic performance. Further investigation found that both radical and non-radical pathway jointly promote the degradation of 2-cp, and the singlet oxygen (O-1(2)) mediated non-radical pathway serve a predominant role. Meanwhile, SO4 center dot- and (OH)-O-center dot also accelerated this process. The possible degradation pathway was proposed by identifying the intermediates of 2-cp degradation. This work provides some new ideas for the design of multimetal MOFs for environmental remediation.

Automated summary

Based on two different topologies of MOFs, core-shell bimetallic MIL-101/ZIF-67(x) (M/Z(x)) materials were successfully synthesized for the activation of peroxymonosulfate (PMS) self-decomposition in order to degrade 2-chlorophenol. The M/Z(x) exhibited not only the advantages of single-metal MOFs such as high surface area and pore volume, but also superior catalytic performance. Further investigation revealed that the catalytic degradation of 2-chlorophenol was promoted by the synergistic effect of cobalt and iron active sites in M/Z(x), which enhanced the Co2+/Co3+ redox cycle. Radical and non-radical pathways contributed to the degradation, with singlet oxygen (O-1(2)) playing a predominant role in the non-radical pathway. Sulfate radical (SO4 center dot-) and hydroxyl radical ((OH)-O-center dot) also accelerated the degradation process.