气体扩散电极制备条件与氧还原反应活性关系的研究

Relationship between the preparation conditions of gas diffusion electrodes and their activities in the oxygen reduction reaction

在改变催化层中聚四氟乙烯(PTFE)、造孔剂含量和热压压力等条件下制备气体扩散电极,通过计时电位法、阴极极化曲线对气体扩散电极进行测定,并将其结果用最小二乘法拟合得出电极的制备条件与氧气还原反应电化学参数之间的关系。电化学测试结果表明,各种条件下制备的电极的阴极极化过程都符合Rho提出的半经验公式规律;当气体扩散电极催化层PTFE面密度3.33 mg/cm2、造孔剂(NH4)HCO3面密度1.05 mg/cm2以及热压压力3.69 MPa时,气体扩散电极的氧还原活性最佳。

A series of gas diffusion electrodes have been prepared under different conditions including varying polytetrafluoroethylene（PTFE） contents, pore-forming agent contents and hot pressing pressure. The relationship between the preparation conditions and the electrochemical parameters of the oxygen reduction reaction （ORR） was studied by cathodic polarization tests and their least-squares simulations and chronopotentiometry curves of the gas diffusion electrodes. The following electrochemical measurement were obtained. All the cathodic plarization proces- ses of the electrodes were found to accord well with the the semi-empirical equation proposed by Rho. The ORR at the gas diffusion electrode exhibited the best activity when the surface densities of PTFE and （ NH4） HCO3 were re- spectively 3.33 mg/cm2 and 1.05 mg/cm2 in the catalyst layers, and the hot pressing pressure was 3.69 MPa.