Synthesis and characterization of potassium metal/graphitic carbon nanofiber intercalates.

Direct reaction of herringbone, platelet, or narrow, tubular herringbone graphitic carbon nanofibers (GCNFs) with molten potassium gives K/GCNF intercalates with stoichiometric control of potassium loading. Intercalate formation is confirmed by powder X-ray diffraction and micro-Raman spectroscopy. K/GCNF intercalates act as radical-anion alkene polymerization catalysts and reduce water with stoichiometric formation of hydrogen gas. Stage-1 K/narrow, tubular GCNF intercalate exhibits thermionic emission at 300 degrees C. Stage-1 K/herringbone GCNF intercalate is an excellent thermionic emitter having high thermal stability up to 1000 degrees C. K/GCNF intercalates have much reduced work functions of ca. 2.2 eV with localized emission showing a work function of 1.6 eV.