A Novel Catalyst Layer Structure And Its Study For Proton Exchange Membrane Fuel Cell

Proton exchange membrane fuel cells(PEMFCs) are an attractive technology and stand on the brink of large-scale commercialization, due to their high energy conversion efficiency and zero emission. However, several drawbacks are hampering its commercial realization, including the high cost and poor durability. Platinum, as one kind of noble metals, is widely used as catalyst for PEMFCs. It is have a very important significance to maximize the effectiveness of catalyst, improve its catalyst activity and life. Aiming at the above-mentioned problems, we proposed a novel catalyst layer structure concept and showed our efforts to solve these problems.This novel catalyst layer structure was prepared by in-situ grown Ptnanowires(Pt-NWs) in the carbon matrix. The carbon matrix was composed by carbon power and ionomer. The Pt-NWs were prepared by chemical reduction of H2PtCl6 by HCOOH. Transmission electron microscopy(TEM), scanning electron microscopy(SEM), polarization curve tests, electrochemical impedance spectroscopy(EIS), and cyclic voltammetry(CV) were employed to evaluate this Pt-NW catalyst layer structure and performance.Comparing with the conventional catalyst layer, this novel Pt-NW catalyst layer shows several unique characteristics:(1) the as-prepared PtNWs possess single crystalline structure,(2) the Pt-NWs grow along the secondary pores in the catalyst layer,(3) for the first time, the catalyst layer with a continuous gradient distribution is successfully prepared,(4) even at a lower Pt loading and smaller electrochemical active area, the novel catalyst layer has improved electrochemical performance,(5) the simple manufacturing process and high performance make the method a promising method for MEA preparation for commercial applications.Through systematic research on all parameters, the optimized catalyst layer structure is implemented. The further improved structure and performance is achieved by changing the matrix.