聚苯胺-聚醚嵌段共聚物对CNT担载Co/Fe纳米粒子的结构调控及其氧还原反应

To increase the activity while decrease cost in cathode catalyst for proton exchange membrane fuel cell is significant for new energy application, and the nano-composite of non-Pt catalyst loaded on nitrogen containing carbon support provides effective route for this purpose. In this application, we planned to synthesis adaptable molecular weight of PANI-b-PEO block copolymer initially. With π-π interaction between the block of PANI and carbon nanotube (CNT), PANI-b-PEO non-covalent modified CNT ((PANI-b-PEO)-CNT) composite support can further be obtained. Therefore, the wrapping density of (PANI-b-PEO)-CNT can be adjusted by stoichiometric ratio of PANI-b-PEO and CNT, making composite support active. On the above basis, Co and Fe composited nanoparticles can be IN-SITU controllably loaded on the composite support by Turkvevich method, to form (CoxFey /(PANI-b-PEO)-CNT), whose electo-catalysis of oxygen reduction reaction can be systematically studied. Further adjust for PANI and PEO block molecular weight, the hydrophobic and hydrophilic micro-interface for composite support can be optimized thus increasing oxygen transfer. All these efforts will provide new methods and theories for high performance and low cost of cathode catalyst for novel cells.

提高质子交换燃料电池的阴极催化剂活性、降低成本对新能源应用具有重大意义，非Pt催化剂的纳米复合与含N碳化物载体的担载为此开辟了有效途径。本申请拟首先合成分子量适宜的聚苯胺-聚醚嵌段共聚物(PANI-b-PEO)，进而通过PANI嵌段与碳纳米管(CNT)的π-π作用，制备PANI-b-PEO非共价修饰CNT ((PANI-b-PEO)-CNT)复合载体，从而通过(PANI-b-PEO)与CNT计量比调控(PANI-b-PEO)-CNT包覆密度，促进复合载体活化。在此基础上，通过改进Turkevich法，实现以Co、Fe的纳米复合粒子在复合载体上的原位可控担载(CoxFey /(PANI-b-PEO)-CNT)，系统研究其电催化氧还原反应，并通过调节PANI、PEO嵌段分子量优化复合载体亲水/憎水微观界面以强化氧气传输，从而为新型电池阴极催化剂的高性能化和低成本化提供新方法和理论基础。

本课题发现：Pt NPs 与聚苯胺嵌段聚合物(PANI-b-PEO)在碳纳米管（CNT）表面易形成 “弓”形组装模式，其较优催化性能可能出现“弓”形模式分离，改进PANI-b-PEO分子设计十分必要。同时，本课题组首次发现金属离子- ANI（苯.胺）的自发、可控自组装行为，从而可制备Co-PANI/CNT(钴-聚苯胺/碳纳米管)、Fe-PANI/CNT(铁-聚苯胺/碳纳米管)、Pt-PANI/CNT(铂-聚苯胺/碳纳米管)等催化剂，通过结构深入，澄清了氧还原行为（ORR）在酸、碱条件的活性、稳定性，其中Fe系达到商业Pt催化剂0.9倍活性水平，并首次挖掘出Fe系催化剂的氢氧化行为，研发Pt系催化剂达到商业Pt催化剂2~4倍的活性水平，并通过了电池验证。通过EIS研究了甲醇电催化时的“负电阻”现象、氧还原行为（ORR），为传质、表面活性、表面吸附提供了关键研究手段。上述研究将显著促进燃料电池的科学化认识，促进其应用进展。