负载酞菁铁的氮掺杂中空碳球的电催化氧还原性能

Iron Phthalocyanine Coated Nitrogen-doped Hollow Carbon Spheres for Efficient Catalysis of Oxygen Reduction Reaction

开发低成本、高性能的氧还原反应(ORR)催化剂是当前的研究热点.虽然酞菁铁(FePc)在几十年前就被证明能高效地电催化氧还原反应,但由于其电子传导性和稳定性较差,无法取代商用的Pt/C催化剂.氮掺杂碳材料不仅化学性质稳定、电子传导性好,还有一定的氧还原催化活性.本文首先制备了聚苯乙烯@聚多巴胺球前驱体,经过高温碳化后制得了氮掺杂中空碳球,进而负载酞菁铁后制备了负载酞菁铁的氮掺杂中空碳球复合材料(FePc-NHCS).通过调整煅烧温度和酞菁铁的负载量,可进一步调控FePc-NHCS的多孔结构、石墨化程度、氮掺杂的种类与含量及酞菁铁的负载状态.优化后的FePc-NHCS在碱性电解质中显示出优异的ORR催化活性,其半波电位和稳定性均高于商用Pt/C催化剂.研究结果表明,掺杂与复合是增强单项催化组分活性的有效途径.此外,通过调控催化剂的结构和组分也能有效地优化催化剂的氧化还原性能.

It is imperative to develop low-cost and high-performance catalysts for oxygen reduction reaction(ORR).Although iron phthalocyanine(FePc)has been proved as an efficient catalyst for ORR decades ago,it cannot replace commercial Pt/C due to its poor electronic conductivity and unsatisfied stability. Considering the chemical stability,high electronic conductivity,and intrinsic catalytic activity of nitrogen-doped carbons,herein,FePc coated nitrogendoped hollow carbon(FePc-NHC)has been fabricated by carbonization of polystyrene@polydopamine spherical precursors,followed by the loading of FePc. A series of hollow spherical FePc-NHCS samples was prepared by adjusting the pyrolysis temperature and loading amount of FePc. Benefiting from the hierarchical porous structure,high specific surface area,proper nitrogen doping,and FePc loading,the optimized FePc-NHCS displayed an excellent catalytic activity for ORR in alkaline electrolyte,with a remarkable long-term stability and a high half-wave potential of 0.862 V(vs. RHE),outperforming Pt/C(0.848 V). This work proved that hybridization is an effective pathway to strength the positive properties of each component. Also,structural and compositional modification is efficient to optimize the ORR performance of a catalyst.