3D V2O5-MoS2/rGO nanocomposites with enhanced peroxidase mimicking activity for sensitive colorimetric determination of H2O2 and glucose

In this work, we reported a novel nanozyme (3D V2O5-MoS2/rGO) by decorating MoS2 nano-flowers and V2O5 nanoparticles on reduced graphene oxide (rGO). The 3D V2O5-MoS2/rGO nanocomposites exhibited intrinsic peroxidase mimicking activity and catalyzed the oxidation of 3, 3', 5, 5'-tetramethylbenzidine (TMB) to produce a blue colored product in the presence of H2O2. Compared with horseradish peroxidase (HRP), 3D V2O5-MoS2/rGO nanocomposites displayed high catalytic velocity (Vmax) and affinity (Km) for substrates (H2O2 and TMB). The study of the catalytic mechanism showed that the reduction of V5+ and the oxidation of S2- in the 3D V2O5-MoS2/rGO nanocomposites accelerate electron transfer between H2O2 and TMB, which enhanced the peroxidase mimicking activity of 3D V2O5-MoS2/rGO nanocomposites. The as-synthetized 3D V2O5-MoS2/rGO could be used for the colorimetric detection of H2O2 in the range of 20.00-800.00 μM with the LOD of 12.40 μM (3σ/S). Moreover, the 3D V2O5-MoS2/rGO could also be used for the detection of glucose in the range of 4.00-300.00 μM with the LOD of 3.99 μM (3σ/S). In addition, the as-synthetized novel peroxidase mimics has good applicability for sensitive colorimetric determination of glucose in human blood samples and artificial urine samples, and has broad application prospects as a multi-functional sensing platform in clinical diagnosis.