A core-shell heterostructured hybrid nanomaterial of bi-metallic MOFs and COFs: Improved 2,4,6-trichlorophenol charge collection

In this study, a monomer-induced self-assembly growth path was proposed for the controllable synthesis of core-shell heterostructured MOF(Fe/Cu)DT@COF hybrid nanomaterial (MOF, metal-organic framework; COF, covalent-organic framework; DT, 2,5-dimethoxyterephaldehyde), which exhibited highly ordered crystal structure and uniform distribution. Then, 2,4,6-trichlorophenol (TCP) was selected as the target molecule to construct the MOF(Fe/Cu)DT@COF electrochemical sensor for selective and sensitive detection. Relevant investigations indicate that the assembled columnar COF shell is availably able to promote the diffusion of TCP to the bimetallic active center of MOF, which exhibits excellent electrocatalytic performance via the synergistic effect. The two linear dynamic ranges of current response under the optimal conditions (pH = 8.0) are 0.01–10 and 10–900 μmol L-1, respectively, with a 0.003 μmol·L-1 (S/N = 3) detection limit. On this sensor platform, there was also negligible interference from other ions that were present, which allowed the sensor based on MOF(Fe/Cu)DT@COF to detect low abundance TCP from actual samples. The article will inspire engineers and scientists working in the field of MOFs/COFs, whose concerted efforts will lead to more novel nanomaterials and will speed up the development of electrochemical sensing based on heterostructured hybrids of MOFs and COFs. [Display omitted] •The core-shell structured MOF(Fe/Cu)DT@COF was successfully constructed.•The resultant material enhanced TCP electrochemical sensing performance.•The synergistic effect of bi-metallic MOF and COF was discussed in detail.•The sensor could detect TCP in real samples with satisfactory recoveries.