Study On Oxygen Reduction Electrocatalysts Of Heteratomic Doped Carbon Materials Based On The Complexes

Fuel cells,metal-air batteries and other systems have attracted wide interest because of their high efficiency and non-pollution.The oxygen reduction reaction（ORR）plays a very important role in the electrochemical energy conversion and storage system,however,the delay of cathodic oxygen reduction rate seriously restricts the development of oxygen reduction equipment.At present,Pt-based materials is the most advanced electrocatalysts in oxygen reduction reaction,but its high cost and limited reserves,poor durability and chemical sensitivity seriously limit the development of energy equipment.Therefore,it is very important to research platinum-free or low-platinum oxygen reduction catalysts.In this paper,we report the synthesis and ORR properties of various heteroatom-doped carbon materials prepared with metal complexes as precursors.（1）A nitrogen-doped carbon material,Co₃O₄@N/C,was synthesized by use of a self-prepared Co-MOF as precursor and g-C₃N₄ as N source.The Co₃O₄@N/C catalyst exhibits the ORR performance close to the commercial Pt/C in 0.1 M KOH with a half-wave potential of 0.8 V while the catalyst has a better stability than Pt/C.The good performance is due to the good synergistic effect of Co₃O₄ metal nanoparticles and nitrogen-doped carbon layer.（2）A non-metal carbon material,（NPSpC）,was synthesized by use of ZIF-8 as carbon source,sodium phytate as phosphorus source and dodecyl mercaptan as sulfur source.The NPSpC catalyst has a large surface area and the synergy of nitrogen,phosphorus and sulfur atom is good to increase the number and exposure of ORR catalytic activity sites.The NPSpC catalyst showed similar ORR properties to commercial Pt/C in acid,medium and alkaline solution,and its resistance to methanol and long-term stability was better than that of Pt/C.（3）A bimetallic nitrogen-doped carbon material,NiFe@NPC,was synthesized by use of Fe（NO₃）₃?9H₂O,Ni foam,Zn（NO₃）₂?6H₂O and 2-methylimidazole.The NiFe@NPC catalyst has excellent ORR performance and stability in both acidic and alkaline media,which is mainly due to the bimetallic active center of the catalyst and coated by nitrogen doped carbon layer.The two parts have a good synergistic effect,which makes the catalyst more stable.