Sensitive electrochemical sensor for dihydroxybenzene isomers based on single-atom Cu catalyst derived from Cu-ZIF-8

Single-atom catalysts (SACs), with advantages of high catalytic activity, high stability and high selectivity, have displayed a perfect performance in electro- chemically sensing small biological molecules. However, SACs were in scare case to be employed in electroanalysis on dihydroxybenzene isomers. Hence, high- temperature pyrolysis-derived Cu-based single-atom catalyst (Cu-SAC) was obtained and then was observed to own an outstanding property on detecting dihydroxybenzene isomers. Cu-SAC exhibited a large specific surface area and highly dispersed active sites that were uniformly distributed on N-doped porous carbon characterized by XRD, SEM, TEM, HAADF-STEM, XPS and BET. The electrochemical sensor based on Cu-SAC demonstrated a wide detection range of 1–100 μM and the significant sensitivity for the simultaneous measurement of hydroquinone (HQ) and catechol (CC) under optimal conditions. The detection limits for both isomers were around 0.11 μM for HQ and 0.33 μM for CC, respectively. Additionally, this sensor was successfully utilized to identify HQ and CC in a tap water sample.