Preparation Of GR-MTPP Nanocomposite And Its Applications For Electrochemistry

This paper mainly studied the synthesis of a series of graphene-metallo-tetraphenylporphyrin （GR-MTPP） nanocomposite which is prepared via Ï€-Ï€ noncovalentinteraction and their catalytic action in micro-molecule, which mainly contains three parts asfollows:（1） MTPP were synthesized from TPP and many metal elements including Fe, Co, Ni,Cu, Zn, Mn via the coordination effect by the modified Rothemund method. A series ofGraphene-Metallo-tetraphenylporphyrin nanocomposition materials were successfullyprepared by the Ï€-Ï€ stacking super-molecular method. The Fourier transform infrared （FT-IR）spectrum and UV-Visible spectroscopy （UV） showed that intermolecular interactionsimmediately happened after mixing MTPP and GR together. The GR-MTPP were used toelectro-catalytic toward oxygen reduction. It is found that synergistic effect from the specificgood active site of many important enzymes of MTTP and the large electro-active surfacearea and fast charge transfer of GR contribute to electro-catalytic toward oxygen reduction.The GR-MTPP film electrode exhibits an enhanced electro-catalytic activity toward oxygenreduction. In especial, the GR-FeTPP film electrode showed the potential peak at-0.24V and85μA current response to eletro-catalytic toward oxygen; the GR-CoTPP film electrodeshowed the potential peak at-0.19V and+0.45V and the current response are larger thanCoTPP film electrode to eletro-catalytic toward oxygen. The GR-MTPP nanocomposie filmsshowed prominent electrochemical response to oxygen, which makes a promising applicationfor electrochemical detection of oxygen.（2） A novel hydrogen peroxide biosensor without enzyme based on the thin film ofgraphene-iron-tetraphenylporphyrin （GR-FeTPP） composite which is prepared by dropcoating at a glassy carbon electrode was developed. The synthetic materials werecharacterized by Fourier transform infrared spectrum（FT-IR）, UV-Visible absorption spectrum（UV） and electrochemical impedance spectroscopy （EIS） and the properties of the sensor ofcatalyzed reduction to hydrogen peroxide was investigated. The resulting FeTPP-GR filmshowed excellent electrocatalytic reduction activities toward H₂O₂at peak potential of-0.25V.The current response was linear to H₂O₂concentration with the concentration range from5.0×10^-7to2.0×10^-4mol/L （R=0.999）, and the detection limit is4.1×10^-7mol/L.（3） The novel hydrogen peroxide biosensor and oxygen biosensor without enzyme basedon the thin film of graphene-Cobalt-tetraphenylporphyrin （GR-CoTPP） composite which isprepared by drop coating at a glassy carbon electrode was developed. The as-preparedGR-CoTPP nanocomposite exhibited high electrocatalytic activities toward H₂O₂oxidation and reduction simultaneously. The current response was linear to H₂O₂concentration with theconcentration range from1.0×10^-7to1.8×10^-3mol/L （R=0.998） at the reductive potential of-0.20V and from1.0×10^-7to4.6×10^-4mol/L （R=0.996） at the oxidative potential of+0.50V.The CoTPP-GR nanocomposite exhibited high electrocatalytic activities at the reductivepotential of-0.1V and no electrocatalytic activities at the oxidative potential of+0.45Vtoward O₂. The GR-CoTPP biosensor showed good anti-interfering ability towards oxidativeinterferences at the oxidative potential and good anti-interfering ability towards reductiveinterferences at the reductive potential.