Fabrication of iron phthalocyanine/graphene microanocomposite by solvothermally assisted π-π assembling method and its application for oxygen reduction reaction

摘要

Catalysts for oxygen reduction reaction (ORR) are the key barriers in direct methanol fuel cells (DMFCs). Despite tremendous efforts, developing ORR catalysts with high activity at low cost remains a great challenge. Here, iron (III) tetracumylphenoxy phthalocyanine microanocomposite (FePc(CP)_4) on graphene (FePc(CP)_4/Gr) as a non-noble catalyst for ORR was prepared by solvothermally assisted π-π assembling method. The FePc(CP)_4/Gr microanocomposite was characterized by UV-vis spectrum, XPS, SEM and TEM. The electrocatalytic activity of the FePc(CP)_4 microano composite for ORR was assessed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) methods. The peak potential for ORR on FePc(CP)_4/Gr composite catalyst was found to be around -0.195V vs. SCE in 0.1 M NaOH solution, which was positive than Pt/C. Rotating disk electrode measurements (RDE) revealed that ORR mechanism was nearly via a 4e~- pathway on the FePc(CP)_4/Gr composite. The FePc(CP)_4/Gr composite catalyst showed good stability, where the peak current density retained 95% of its initial value after repeated 100 cycles. Pt/C catalyst, on the other hand, only retained 82% of its initial current. The peak potential almost barely changed. When 3 M methanol was added, the peak potential shifted slightly and the current changed slightly. So the FePc(CP)_4/Gr composite catalyst for ORR exhibited high-performance activity, good stability and excellent resistance to crossover-effect to methanol.