PtPd nanodendrites supported on graphene nanosheets: A peroxidase-like catalyst for colorimetric detection of H2O2

Well-dispersed PtPd nanodendrites on graphene nanosheets (PtPdNDs/GNs) were synthesized by a simple and green method with the reduction of ethanol. The morphology, structure and composition of the thus-prepared PtPdNDs/GNs were characterized by transmission electron microscopy (TEM), high resolution TEM, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Furthermore, the peroxidase-like catalytic ability of PtPdNDs/GNs was studied and it is interesting that the PtPdNDs/GNs can efficiently catalyze the classical peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). By comparing with mono Pt nanoflowers (NFs)/GNs, Pd nanoparticles (NPs)/GNs, bimetallic PtPd nanoalloys (NAs)/GNs and core-shell Pd@PtNFs/GNs, the PtPdNDs/GNs showed a stronger affinity for TMB with a lower Michaelis-Menten constant (Km) value at an optimum pH of 4.4. Take the advantage of the high catalytic activity, the as-prepared PtPdNDs/GNs was used to develop a novel colorimetric sensor for H2O2 with fast response, wide linear range (0.5-150 mu M) and low detection limit (0.1 mu M). The rapid, simple and sensitive TMB-H2O2-PtPdND5/GN5 sensing platform shows great promising applications in the pharmaceutical, clinical and industrial detection of H2O2. (C) 2014 Elsevier B.V. All rights reserved.