Glucose electrocatalysts derived from mono‐ or dicarbene coordinated nickel(II) complexes and their mesoporous carbon composites

Molecular electrocatalysts that contain a metal atom under precise ligand field in a definite geometry feasible for redox reactions has boundless significance in numerous electrocatalytic reactions. Herein, we report nickel‐based molecular electrocatalysts anchored on the sterically varied 1,2,4‐triazol‐5‐ylidene ligands. The two metal complexes bearing different ligand system wherein one is mono‐NHC nickel(II) complex and the other is a bis‐NHC nickel(II) complex were compared and studied in terms of morphology and electrochemical glucose sensing. The kinetics and sensitivity of the nickel(II) complexes were significantly enhanced by the mesoporous carbon and demonstrated high electrode sensitivity (2.57–124.92 μA mM−1 cm−2) at a fixed potential towards glucose detection. The chronoamperometric studies evidenced the detection of glucose up to 27.5 mM with a linear range of detection up to 9.5 mM (LOD of 44.59 μM). The selectivity towards glucose in the presence of other blood constituents was investigated. Finally, the stability was studied after 18 days of electrode preparation, and negligible variation in the glucose sensing performance was found. The electrocatalysts prepared are found to be the viable candidates for potential engineering high‐performance molecular non‐enzymatic glucose sensor. Two sterically varied nickel NHC complexes wherein one is a mono‐NHC and the other is a bis‐NHC have been prepared and compared as electrocatalysts for glucose sensing applications. It was found that the mono‐NHC nickel(II) complex exhibited superior glucose sensing activity. The addition of mesoporous carbon to the complexes was found to enhance the glucose sensing performance of the complexes with increased sensitivity, increased linear range and decreased limit of detection.