石墨烯载Pt纳米粒子的原位还原制备及氧还原电催化性能

In-situ Synthesis of Pt Nanoparticles on Graphene Nanosheets and Its Electrocatalysis for the Oxygen Reduction Reaction

采用改进的化学氧化还原法(Hummers法)氧化鳞片石墨,再超声振荡剥离得到氧化石墨烯(GO)水溶液.通过聚二烯丙基二甲基氯化铵(PDDA)分子对GO表面功能化,由于带正电荷的PDDA分子功能化的GO与带负电荷的[PtCl6]2-离子间的静电作用,使Pt离子组装到GO表面,再通过原位还原被束缚的Pt离子,同时GO被还原成石墨烯片(GNs),得Pt/PDDA-GNs催化剂.相对空白GNs负载的Pt纳米粒子和商业化Pt/C(JM),Pt/PDDA-GNs催化剂有较高的氧还原活性和稳定性.前者可归因于Pt颗粒尺寸细小和分散度较高,后者是由于PDDA分子与Pt原子间的电子作用及对Pt颗粒的钉扎作用,从而减缓了Pt的氧化和迁移.

Pt nanoparticles were anchored on graphene nanosheets（GNs） with the aid of poly（diallyldime-thylammonium chloride）（PDDA）.The Pt ions were assembled first onto PPDA-modified graphene oxide nanosheets and then the caged Pt ions and graphene oxide were reduced simultaneously by ethylene glycol.As was supported by transmission electron microscopy,Pt nanoparticles were well-dispersed on GNs.Comparing with the commercial Pt/C and Pt/GNs（without PDDA） catalysts,the as-prepared Pt/PDDA-GNs nanohybrid exhibited an enhanced catalytic activity for the oxygen reduction reaction（ORR） and a significant improvement in the electrochemical durability.The enhanced durability could be ascribed to the increased Pt oxidation potential and to a strengthened metal-support interaction.The results show that PDDA plays an important role in the dispersion and stabilization of Pt nanoparticles on GNs,thus leading to an enhancement in both activity and durability of the catalyst for the ORR.This preparation procedure is effective and may be extended to synthesize other metal-graphene composites.