Low temperature pyrolyzed cobalt tetramethoxy phenylporphyrin catalyst and its applications as an improved catalyst for metal air batteries

As an alternative catalyst to replace the expensive platinum-based catalysts for oxygen reduction reaction (ORR) in both proton exchange membrane (PEM) fuel cells and metal–air batteries, tetra methoxyphenyl porphyrin cobalt complex, CoTMPP, has drawn much attention in the areas of ORR catalyst synthesis and characterization. In the present work, CoTMPP is investigated at varying temperatures of pyrolysis, ranging from 410 to 810 °C, to determine the optimal temperature of pyrolysis to produce catalysts with desirable properties. Carbon supported pyrolyzed CoTMPP catalyst (CoTMPP/C) was assessed using X-ray diffraction and Raman, a number of varied electrochemical tests, as well as a single cell test. Through these, it has been found that the CoTMPP/C, pyrolyzed at 410 °C, demonstrates superior catalytic activity towards ORR, and has a higher fuel cell performance than the catalysts pyrolyzed at 800 °C, the industry standard pyrolysis temperature. This paper also utilizes scanning auger microscopy (SAM) to accredit the origin of the increased activity to the bond N–C(O), which plays a major role in catalysis and is decomposed at higher temperatures.