Cobalt-based Nanocrystals/heteroatom-doped Graphene Aerogel As Efficient Oxygen Electrode Catalyst

With increasing attention to energy and environment problems,urgent demand has aroused intensive interest on energy conversion and storage systems with high efficiency,low cost,and environmental friendliness.The electrocatalysts for the oxygen reduction reaction（ORR）and oxygen evolution reaction（OER）are of great significance for different energy technologies such as fuel cells and water splitting.Till now,Pt-based catalysts are usually used catalysts for the oxygen reduction reaction in fuel cells,and Ru-and Ir-based catalysts are frequently utilized catalysts for the oxygen evolution reaction in water splitting.Nonetheless,the high cost,low abundance and poor durability of noble metal catalysts limit the large-scale commercial application.Hence,it is expected that non-precious metal catalysts,which possess efficient and good stability,take the place of noble metal catalysts.In the paper,two non-precious metal catalysts,abbreviated Co/N,P-GA and Co₉S₈/N,S,P-GA,have been prepared by a two-step synthesis method including a hydrothermal reaction and a pyrolysis procedure.The morphologies and structures of the composites were characterized by transmission electron microscope（TEM）,X-ray diffraction（XRD）,Raman and X-ray photoelectron spectroscopy（XPS）,respectively.The catalytic performance of the as-prepared composites was evaluated through test methods including CV、LSV、RRDE and i-t.The results show that the obtained Co/N,P-GA hybrid possesses an excellent catalytic activity for the ORR,and Co₉S₈/N,S,P-GA composite towards the ORR and OER,exhibits a superb catalytic activity.In addition,two fabricated composites also show good durability and excellent methanol tolerance.In an alkaline medium,cobalt-based nanocrystals/heteroatom-doped graphene aerogel hybrids are promising as oxygen electrode catalysts.