Herein, CoN, CuN, and NiN complexes with a 14-membered ring hexaazamacrocycle ligand HHAM were synthesised as precursors for ORR and CORR catalysts a one-pot, gram-scale synthesis procedure, which involved microwave heating for only 10 min. Detailed structures of the obtained 14MR-MN complex were revealed by single-crystal X-ray diffraction measurements.
View Article and Find Full Text PDFNonplatinum metal (NPM) catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) have been developed; however, NPM catalysts still need to be improved in terms of both their catalytic activity and durability. To overcome these problems, an Fe active site contained within a more compact ligand than conventional, porphyrinic, 16-membered ring ligands, or more specifically, a hexaaza macrocyclic ligand with a 14-membered ring (14MR), was developed. In this study, the durability of the Fe-14MR complex was compared to that of Fe phthalocyanine (FePc), which has a 16-membered ring ligand, using in situ X-ray absorption spectroscopy; demetalation of the Fe complexes was directly observed during electrochemical experiments performed under acidic ORR conditions.
View Article and Find Full Text PDFNaturally occurring polysaccharides, such as cellulose, hemicellulose, and chitin, have roles in plant skeletons and/or related properties in living organisms. Their hierarchically regulated production systems show potential for designing nanocomposite fabrication using engineered microorganisms. This study has demonstrated that genetically engineered () individual cells can fabricate naturally composited nanofibrils by simultaneous production of hyaluronan (HA) and bacterial cellulose (BC).
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
December 2015