A Novel Electrocatalyst Pd(II)@Ni₃(HITP)₂ for Ultrasensitive Detection of Chloramphenicol: Experimental and Computational Investigation

Ultrasensitive electrochemical detection on hazardous substances like antibiotics and pesticides is essential but still challenging in rapid test technology. Herein, the first electrode using highly conductive metal-organic frameworks (HCMOFs) for electrochemical detection of chloramphenicol is proposed. The design of electrocatalyst Pd(II)@Ni3 (HITP)2 with ultra-sensitivity in detection of chloramphenicol is demonstrated by loading Pd onto HCMOFs. An ultra-low limit of detection (LOD) of 0.2 nM (64.6 pg/mL) was observed for these materials, which is 1-2 orders of magnitude lower than the other reported materials for chromatographic detection. Moreover, the proposed HCMOFs showed long-time stability over 24 h. The superior detection sensitivity can be attributed to the high conductivity of Ni3 (HITP)2 , and the large Pd loading. The experimental characterizations and computational investigation determined the Pd loading mechanism in Pd(II)@Ni3 (HITP)2 , revealing PdCl2 adsorption on the abundant adsorption sites of Ni3 (HITP)2 . The proposed electrochemical sensor design using HCMOFs was demonstrated to be both effective and efficient, showing that the adoption of HCMOFs decorated with other effective electrocatalysts, which combine high conductivity and high catalytic activity, is of great advantage for ultrasensitive detection.