Varying the morphology of Fe-N-C electrocatalysts by templating Iron Phthalocyanine precursor with different porous SiO2 to promote the Oxygen Reduction Reaction

• Fe-N-C catalysts are prepared from FePc with different heat treatments
• The best Fe-N-C catalyst is prepared through pyrolysis at 850 °C
• Different porous silica are used as template to modify the morphology and porosity
• ORR electroactivity in acidic solution is determined with RRDE and GDE apparatuses
• The best catalyst Fe-N-C/850_mSiO2 presents the highest microporosity

Iron phtalocyanine (FePc) is used as iron/nitrogen/carbon source to synthesized Fe-N-C electrocatalysts for ORR by pyrolysis treatment in inert atmosphere for 2 h. Various temperatures are investigated, and the most favorable temperature, 850 °C, is selected as best temperature to carry out the pyrolysis treatment. To increase the ORR activity, the morphology of the catalysts is on purpose modified with the use of different porous silica (SBA15 in house prepared and commercial mesoporous SiO2) as templating agent during synthesis. The use of the templating agent allows to drastically increase the specific surface area and the microporosity of the catalysts, especially with the use of the commercial mesoporous SiO2. The electrocatalytic activity towards ORR of the catalysts in acid conditions is assessed by RDE and RRDE apparatuses to quantify the hydrogen peroxide production. The Fe-N-C/850_mSiO2 catalyst exhibits higher electroactivity. Furthermore, in the GDE configuration this catalyst reached a mass activity of –1.4 mA mg−1, after IR correction. The chronoamperometry performed at 0.47 V vs RHE shows relatively good stability values up to 60 hours. The catalysts are characterized by means of BET, FTIR, FESEM, EDX, and XPS analyses. The obtained catalysts exhibit a nitrogen content varying from 0.9 to 2 at.% and an iron content from 0.1 to 0.5 at.%.

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