Micro-colloidal catalyst of palladium nanoparticles on polyaniline-coated carbon microspheres for a non-enzymatic hydrogen peroxide sensor

We describe the chemical synthesis of a colloidal micro-catalyst of palladium nanoparticles decorated on polyaniline-coated carbon microspheres (PdNP-PANi/CMs). The colloidal PdNP-PANi/CMs were used to modify the electrode interface of a highly sensitive non-enzymatic sensor. The morphology and electrochemical properties of the catalyst and electrode were characterized by SEM, EDX, FTIR, XRD, and electrochemical methods. Hydrogen peroxide (H2O2) was the model analyte. The catalytic efficiency of the PdNP-PANi/CMs/GCE toward H2O2 was evaluated via the scan rate effect and chronoamperometric measurement, which showed a diffusion -controlled process with a high diffusion coefficient (D = (3.4 +/- 0.5) x 10(-3) cm(2) s(-1)) and catalytic rate constant (kcat = (4.50 +/- 0.02) x 107 mol(-1) cm(3) s(-1)). A response time within 5 s and excellent sensitivity (234 mu A mM(-1) cm(-2)) were obtained. The proposed electrode provided a linear concentration range between 0.002 and 10 mM with a limit of detection of 0.70 mu M. Operationally, the PdNP-PANi/CMs/GCE exhibited good electrocatalytic stability and good repeatability, reproducibility, and selectivity. The applicability of the developed sensor was proved by the determination of H2O2 in human seminal fluid. Recoveries were in the range of 97 +/- 2% to 102 +/- 3%. The good performances of this colloidal micro-catalyst showed the potential of this material in other sensing, biosensing, and biofuel cell applications.

Automated summary

The chemical synthesis of a colloidal micro-catalyst of palladium nanoparticles decorated on polyaniline-coated carbon microspheres (PdNP-PANi/CMs) is described in this study. The catalyst was used to modify the electrode interface of a highly sensitive non-enzymatic sensor, showing excellent electrocatalytic stability and good repeatability, reproducibility, and selectivity. The developed sensor demonstrated its applicability in detecting hydrogen peroxide in human seminal fluid, with recoveries ranging from 97 +/- 2% to 102 +/- 3%. The good performances of this colloidal micro-catalyst suggest its potential for other sensing, biosensing, and biofuel cell applications.