Photoelectrochemical sensing for hydroquinone based on porphyrin-functionalized Au nanoparticles on graphene

A novel light "on-off" photoelectrochemical sensing for the sensitive determination of hydroquinone was developed based on the porphyrin-functionalized Au nanoparticles on graphene (porphyrin/AuNPs/graphene). Gold nanoparticles (AuNPs) were firstly modified onto graphene sheets using NaBH4 as reductant and the porphyrin/AuNPs/graphene nanocomposites were then synthesized by self-assembly decoration of sulfhydryl porphyrin on AuNPs modified graphene sheets by S-Au bond. The porphyrin/AuNPs/graphene nanocomposites were characterized by transmission electron microscopy, X-ray photoelectron, and ultraviolet-visible absorption spectroscopies. The nanocomposites showed good dispersion in water and on indium tin oxide (ITO) surface. The resulting porphyrin/AuNPs/graphene modified ITO electrode showed good photoelectrochemical behavior toward the oxidation of hydroquinone (HQ) at 0V under white light illumination. The proposed photoelectrochemical method could detect hydroquinone with a wide linear response ranging from 20 to 240nM (R=0.9914). The detection limit was 4.6nM for HQ (S/N=3). Thus, the nanocomposites would be expected to be a novel photoactive material for photoelectrochemical biosensing.