Preparation Of Porous Carbon And Metal Phthalocyanine Supported With Porous Carbon As Novel Catalyst For Magnesium Air Fuel Cell

Metal air fuel cells(MAFC) gained more attentions due to the advantages of abundant raw materials, low cost, environment-friendly. The performance of metal air fuel cells was mainly depended on air cathode. The catalyst played a key role on the performances of the air cathode.Considering the reason of low oxygen transport efficiency of traditional carbon materials, three kinds of porous carbon were synthesized with good expectations. The coal tar pitch was selected as carbon sources, nano-sized MgO, Fe2O3 and Fe(OH) 3 are chosen as the templates in the process of preparation of porous carbons. Using nitrogen adsorption, adsorption desorption isotherms and pore size distribution were obtained. The structures and morphologies of porous carbons were characterized by employing XRD, SEM, TEM and XPS. The results indicated the materials were amorphous with smaller graphited degree and obvious porous structures. The optimum conditions of getting porous carbons were obtained by employing the electrochemical tests in alkaline environment.Phthalocyanine cobalt(PcCo) was loaded on three kinds of porous carbons to get the catalysts. The structures and morphologies of catalysts were characterized by using XRD, SEM, TEM and XPS, the results showed that the catalysts were amorphous; PcCo distributed uniformly on porous carbons and the active center were Co-N4 in phthalocyanine rings. The optimum conditions of preparing catalysts were obtained: porous carbons: PcCo=1:1(mass ratio), heating temperature of 400 oC. Electrochemical testing results showed that the onset potentials of PcCo/PC1、PcCo/PC2 and PcCo/PC3 catalyst(obtained under the optimum process conditions) were 0.07 V, 0.04 V and 0.06 V, respectively, and the electron transfer numbers were 3.78, 3.65 and 3.72. Cyclic voltammetry, linear sweep voltammetry and chronoamperometry tests were employed to measure the electrochemical stability of the catalysts, the results indicated the catalysts had good durability and nice electrochemical stability in alkaline environment.The performances magnesium fuel cells were tested by using the home-made catalysts. The single cell was assembled and tested to investigate the affection of different gas diffusion layer with different thickness for MAFC, the result showed that the proper thickness was 0.1mm, and the peak power density reached 87.9mW cm-2. Change different carbon materials including PC2, PC3, SWCNT, MWCNT and C as supporters to measure the performances of MAFCs. The peak power density of PcCo/PC1、PcCo/PC2、PcCo/PC3 were 87.9、86.7 and 82.8mW cm-2, and they all showed nice stability during the test of constant current density at 50mAcm-2 for more than 6h.