Fabrication of a sensitive amperometric sensor for NADH and H2O2 using palladium nanoparticles-multiwalled carbon nanotube nanohybrid.

Palladium nanoparticles decorated multiwalled carbon nanotubes (PdNPs-MWCNTs) were synthesized and simply cast on the surface of a glassy carbon electrode (GCE) to prepare an amperometric sensor. The fabricated sensor (PdNPs-MWCNTs/GCE) showed excellent electrocatalytic activity towards NADH and H2O2 oxidation and H2O2 reduction. A fast, linear and highly sensitive response was observed for NADH in the concentration range between 0.1 and 200 μM with a detection limit (S/N=3) of 32 nM. Also, the sensor exhibited fast and sensitive responses (<2 s) towards H2O2. The sensitivity and detection limit for H2O2 at the operating potential of +0.35 V were 167 nA μM(-1)cm(-2) and 1.2 μM, respectively and better than those obtained at the operating potential of -0.25 V (68 nA μM(-1)cm(-2) and 14 μM). Moreover, further modification of the proposed sensor by glucose oxidase led to the fabrication of a glucose biosensor with satisfactory performance.