Influence of different transition metals on the properties of Me-N-C (Me = Fe, Co, Cu, Zn) catalysts synthesized using SBA-15 as tubular nano-silica reactor for oxygen reduction reaction

Different Me-N-C catalysts for oxygen reduction reaction (ORR) are synthesized using Me(II)-phthalocyanines (Me = Fe, Co, Cu, Zn) as a unique precursor molecule, and SBA-15 silica as a sacrificial template. The influence of different transition metals on the pyrolysis process and the consequent physical chemical properties of the final catalysts were investigated using different characterization techniques such as N-2 physisorption, FESEM, EDX, XPS, XRD, and thermogravimetric analysis coupled with mass spectrometry (TGA-MS). The ORR activity and selectivity toward a complete 4-electrons reaction were assessed by RDE analysis in alkaline conditions. The ORR activity of the different Me-N-C catalysts decreases in the order Fe > Co > Cu > Zn approximate to H. Microporosity, pyridinic nitrogen content and temperature at which H-2 starts to be detected during the pyrolysis are directly related to the ORR activity of the different catalysts. (C) 2016 Hydrogen. Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.