| Poly-1,5-diaminoanthraquinone (P1,5-DAAQ) is a new conducting polymer. Its electrochemical reaction includes quinine / hydroquinone (Q/HQ) redox reactions and anions doping/undoping process which is similar to the electrochemical behavior of polyaniline (PANI). These two electrochemical reactions happens in one polymer macromolecule, which can not only improve the structure of aminoanthraquinone polymer, but also provides a better electrochemical activity.The electrocatalysis for oxygen reduction reaction (ORR) has recived much attention in the researches on chemical modified electrode. It has been proved that surface confined quinones can greatly impove the electrocatalytic activity for ORR. Poly-aminoanthraquinone modified electrode is more stable, more easily prepared, and can provide higher surface concentration of reactive sites compared with other quinones modified electrode by adsorpsion or doping. Moreover, poly-aminoanthraquinone with the coexistence of anthraquinone fuction group and chain structure similar to PANI provides a new method for preparation of anthraquinone modified electrode with high electrocatalytic activity for ORR.P1,5-DAAQ have been synthesized by electrochemical oxidative polymerization on the Pt electrode in our research. Its electrochemical characteristics, stability, and electrocatalysis for ORR have been investigated using scan electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and various electroanalytical techniques such as cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS).P1,5-DAAQ was synthesized by CV on the Pt electrode which is an ultra thin, homogeneous, and dense polymer film. The electropolymerization process of 1,5-DAAQ can be strongly influenced by the temperature. As a result, the best characteristic for P1,5-DAAQ can be obtained when the electropolymerization process is controlled at 10℃. The electropolymerization process of 1,5-DAAQ has been investigated by CV, FTIR and SEM. It has been proposed that the electropolymerization consists of two phases: the deposition of P1,5-DAAQ from the oxidation of 1,5-DAAQ monomers, and the polymer growth process consist of two-dimension and three-dimension growth. The electrochemical characteristics and stability of P1,5-DAAQ has been investigated in different acidic aqueous solution by electrochemical methods and FTIR. It has been proved that ion transfers are different between oxidation and reduction processes, and are profoundly influenced by the sizes of ion radius during the redox process of P1,5-DAAQ in acid solution. The H+ transfer is diffusionless, while the insertion/expulsion of big aqua anions is controlled by diffusion. A model has been proposed to describe these ion transfer processes. The diffusion coefficients of aqua anions in P1,5-DAAQ are in the order of Cl- > SO42-> NO3-> PO43-. As a result of stability research, degradation of polymer exists not only in overoxidation, but also in stable redox reaction. The degradation rates of P1,5-DAAQ at reversible potential region from -0.2 to 0.75 V obey the apparent first-order kinetic, and the degradation rate constants are 2.04, 4.93, 2.59, 3.03×10-5 s-1 in HC1, H2SO4, HNO3, and H3PO4, respectively. According to FTIR and CV, the quinone-like sturcture is destroyed, accompanied with conjugation length of the polymer'sπ-bond decreased and chains in polymer broken and recombined with anions combined to the polymer, when P1,5-DAAQ is potentiodynamically overoxidized at 1.5 V.The P1,5-DAAQ modified Pt electrode has shown electrocatalytic activity for two-electron ORR with oxygen reduction peak at about 0.39 V in 0.1 M H2SO4. The effects of P1,5-DAAQ morphologies and the pH of electrolyte on the electrocatalytic behaviors of P1,5-DAAQ for ORR have been investigated using CV, CA and EIS measurements. We propose two different O2-transport processes on electrodes modified with thin P1,5-DAAQ and thick P1,5-DAAQ. Together with the quantitative analysis with O2-transport dynamics, electron-transfer resistance, and catalytic reaction rate during ORR, thin P1,5-DAAQ electrode performs better electrocatalysis for ORR for its plane morphology, although thick P1,5-DAAQ provides higher real surface area and more reactive sites which is beneficial for ORR within a short time. The ORR electrocatalytic activity for the Pt/P1,5-DAAQ electrode decreases with the increasing of pH of electrolyte, and the degradation of P1,5-DAAQ.A series of experiments have been carried out to investigate the application of the Pt/P1,5-DAAQ electrode in electro-Fenton system. It has been found that this electrode can electrogenerate H2O2 at 0.2 --0.2 V. The H2O2 generation rate and current efficiency and its effect factors have been investigated. Besides, this electrode has also shown electrocatalysis for Fe3+ reduction. When the Pt/P1,5-DAAQ electrode is used as an oxygen reduction cathode in electro-Fenton system, bromamine acid (BA) can be degradated. The competition between main reduction reactions on this electrode has been investigated by EIS. The influence of oxidative degradation ability for this electro-Fenton system has been analyzed with the degradation kinitics for BA.
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