סמינר כימיה פיזקאלית ואנאליטית
מרצה: Dr. David Eisenberg
מיקום: חדר סמינרים פקולטי
Efficient oxygen reduction holds the key to practical fuel cells and metal-air batteries. Most of today’s oxygen cathodes are based on platinum catalysts. In theory, fuel cells with such cathodes could power cars for mass transportation – but there is simply not enough platinum on Earth to do this.
We have discovered a new family of nitrogen-doped carbons with excellent activity towards the oxygen reduction reaction in alkaline solutions. These carbons are particularly simple to synthesize on a large scale. They exhibit hierarchical micro/meso/macro porosity, which is great for electrocatalysis because it maximizes both surface area and mass flow through the material. Moreover, the mesopores are lined with a network of highly graphitic shells, boosting conductivity. This useful structure emerges spontaneously through a combination of in situ templating, etching by pyrolysis gases, and graphitization catalysis on MgO nanoparticles.
Understanding the growth of catalytically active carbon materials is a crucial challenge. Our carbons suggest a new paradigm for investigating carbon catalysis and growth: simple variations in the structure of the precursor salts lead to controlled variations in the microstructure of the final carbons. In turn, this leads to control of electrochemical reactivity, e.g. for O2 reduction and electrochemical supercapacitance.