氢燃料电池氧还原催化剂Fe-N_(4)/C合成中的问题及建议

Problems and Suggestions in the Synthesis of Fe-N_(4)/C Oxygen Reduction Reaction Catalysts for Hydrogen Fuel Cell

通过分析现有文献和技术方案发现,氢燃料电池氧还原催化剂Fe–N_(4)/C合成过程中存在2个关键问题,即过量的氮源会热解产生大量HCN、NO_(x)等剧毒物、污染物,以及氮源不能在碳基质上有效地形成与铁4配位的Fe–N_(4)/C。针对这2个问题,建议加强热解条件下铁离子和氮原子的转化及其在碳基质中的迁移过程研究,重点研究热解过程中氮配位体前身物形态的演变、氮原子在碳基质中的定向重排、碳基质上氮配位体的形成及其锚定铁离子的机理。氮原子定向重排于碳基质上,一方面,氮原子获得高效利用,减少合成过程中过量氮源热解生成的大量HCN和NO_(x)等污染物,过程环保;另一方面,重排于碳基质上的氮原子与铁离子络合,形成具有高氧还原反应(ORR)活性、高稳定性的4配位Fe–N_(4)/C结构,进一步推动以非贵金属催化剂取代贵金属催化剂Pt/C在氢燃料电池中的应用。

Based on the existed literatures and methods,it was found that the synthesis of Fe–N_(4)/C catalysts for fuel cell oxygen reduction reactions had two key problems,including production of large amounts of highly toxic substances and pollutants such as HCN and NO_(x) during the pyrolysis of nitrogen source,and the excessive nitrogen source could not form effective tetracoordinated compounds Fe–N_(4)/C with iron ions on carbon matrixes.Aiming at the two issues,it is suggested to strengthen the research on the conversion of iron ions and nitrogen atoms and their migration process on carbon matrixes during pyrolysis,and to focus on the evolution of precursor of nitrogen ligands,the oriented rearrangement of iron and nitrogen atoms on carbon matrixes,and the formation of nitrogen ligands on carbon matrix and the mechanism of anchoring iron ions during pyrolysis.The nitrogen atoms are oriented rearranged on the carbon matrixes,results in the efficient utilization of nitrogen atoms and reducing the production of pollutants including HCN and NO_(x) from the pyrolysis of excessive nitrogen source,which is more environmental friendly;on the other hand,nitrogen atoms that rearranged on the carbon matrixes form a tetracoordinated Fe–N_(4)/C structure with high oxygen reduction reaction(ORR)activity and high stability by complexation with iron ions,promoting to substitute the application of noble metal catalysts Pt/C with non-noble metal catalysts in hydrogen fuel cells area.