Synergetic catalysis of ligand connecting MOFs@MOFs composites in electrochemical detection of P-Chlorophenols

P-Chlorophenols (4-CP) are known as persistent toxic compounds for their acute toxicity and poor biodegradability. When the concentration of phenolic substances in water reaches 0.1005 mg/L, it becomes undrinkable. As a result, the detection of this human-toxic compound was indispensable. Hence, the high sensitivity and absorption ability of MOFs@MOFs composites (HP-UIO66@Ni-BDC) was applied to detect the 4-CP, which was constructed by using the ligand defect NH2-UIO-66 and Ni-BDC via a ligand linking approach. The improved performance of the materials compared to bare MOFs was attributable to the enhanced catalytic ability by the interaction of the MOFs and the high affinity between the 4-CP and the MOFs@MOFs composites (the electron donor-acceptor interaction and π-π stacking interaction). The electrochemical results illustrated the satisfactory electrochemical performances of modified GCEs toward 4-CP, such as the low limit of detection (LOD = 0.328 μM), wider linear detection range from 10 to 160 μM, and good stability and selectivity. Besides, the recovery experiments’ results have shown that the electrochemical sensor could be used in the actual sample detecting. All the results suggested that the prepared HP-UIO66@Ni-BDC composites could serve as a prospective sensor for the real-time detection of 4-CP.