Pt deposited on sea urchin-like CuCo2O4 nanowires: Preparation, the excellent peroxidase-like activity and the colorimetric detection of sulfide ions

Detecting of sulfur ions (S2-) in environment is critical to human health. In this work, a fast and convenient colorimetric sensing platform for S2- was developed. In detail, Pt deposited on sea urchin-like CuCo2O4 nanostructures (Pt/CuCo2O4) was synthesized and demonstrated to possess enhanced peroxidase-like performance, similar to the natural horseradish peroxidase (HRP). Pt/CuCo2O4 can catalyze colorless 3, 3, 5, 5-Tetramethylbenzidine (TMB) to be oxidized by H2O2 into a blue product (oxTMB). When the above system encounters sulfur ions (S2-), the peroxidase-like activity of Pt/CuCo2O4 is inhibited, accompanied with the color change of reaction solutions. On this basis, a colorimetric sensing platform for S2- can be established. Kinetic experiments verified Pt/CuCo2O4 possessed a higher affinity with substrate than that of HPR. The excellent peroxidase-like performance of Pt/CuCo2O4 was attributed to two active species including hydroxyl radical (•OH) and superoxide radical (•O2-) in the catalytic process. The linear range of the proposed sensing platform for S2- was 0.5–10 μM as well as the low limit of detection is 85.9 nM, much lower than the World Health Organization regulations. The sensing platform had been successfully applied to the detection of S2- in tap water and lake water, which provided a convenient method for detecting S2- in wastewater.