Layer-By-Layer Construction Of Graphene/Iorn Phthalocyanine Composites And Their Application For Oxygen Reduction Reaction

Direct methanol fuel cell (DMFC) have been attracted considerable attention owing to their high-energy conversion efficiency, low operating temperature, low pollutant emission, and ease of handling and processing of the liquid fuels. However, the catalysts for direct methanol fuel cells are mainly based on Pt-based catalysts. However, the high-price and resistance to methanol of Pt will limit the large-scale use of fuel cells. Therefore, the development of ORR electrocatalysts with low-cost, high efficiency and long-term stablility play an important role in promoting DMFC applications.In this dissertation, a series of novel phthalocyanine/graphene composite films (denoted as (MTsPc/PDDA-Gr)n, M=Fe or Co, n represents bilayer number assemblied) were prepared by layer-by-layer (LBL) technique. The resulting phthalocyanine/graphene composites were characterized by UV-vis absorption spectrum, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The electrocatalytic activity of the phthalocyanine/graphene composites toward the ORR was evaluated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) methods. The iron phthalocyanine/graphene composite film fabricated via LBL technique presents a high catalytic activity toward the ORR in alkaline and neutral media. Besides, it was found that the proposed (FeTsPc/PDDA-Gr)4composite film displays significantly enhanced catalystic activity for ORR in neutral medium. Furthermore, our catalysts show a better long-term stability and tolerance to methanol crossover effect for ORR than the commercial Pt/C. The fabricated iron phthalocyanine/graphene composite film could be used as a substantial alternative for the replacement of Pt-based catalysts in the cathode of fuel cells.