S-doped carbon aerogels/GO composites as oxygen reduction catalysts

摘要

Composites of carbon aerogel and graphite oxide (GO) were synthesized using a self-assembly method based on dispersive forces.Their surface was modified by treatment in hydrogen sulfide at 650 and 800 ℃.The samples obtained were characterized by adsorption of nitrogen,TA-MS,XPS,potentiometric titration,and HRTEM and tested as catalysts for oxygen reduction reactions (ORR) in an alkaline medium.The synergistic effect of the composite (electrical conductivity,porosity and surface chemistry) leads to a good ORR catalytic activity.The onset potential for the composite of carbon aerogel heated at 800 ℃is shifted to a more positive value and the number of electron transfer was 2e at the potential 0.68 V versus RHE and it increased to 4e-with an increase in the negative values of the potential.An excellent tolerance to methanol crossover was also recorded.