Molecular Conformation of Nafion Ionomer on Electrocatalyst Layer Prepared by Screen Printing Technique

摘要

Preparations of Pt/CNT electrocatalyst layer in colloidal and solution state by screen printingtechniques gave different molecular conformation of nafion ionomer. By this technique, low Pt-2 loaded (0.07-0.1 mg/cm ) and thin electrocatalyst were produced with different microstructural surfaceand electrochemical properties depending on organic solvents used. Interaction of nafion ionomer andorganic solvents (isopropanol, tetrahydrofuran and normal-buthyl acetate) promote importantlydifferent performance in the electrode system. Material analysis relevance to electrocatalystperformance was further carried out. Physical properties examination, electrochemical analysis, andperformance evaluation reveal that the best performance of electrocatalyst was produced in thesolution state whereas well-define CNT individually wrapped by ionomer in a homogeneous fashionwas produced. In colloidal state, molecular conformation of nafion ionomer form continuity threedimensional network and blocking pore structure on carbon surface providing low electronconductivity and high mass transfer resistance.