Elucidation of oxygen reduction reaction and nanostructure of platinum-loaded graphene mesosponge for polymer electrolyte fuel cell electrocatalyst
Elucidation of oxygen reduction reaction and nanostructure of platinum-loaded graphene mesosponge for polymer electrolyte fuel cell electrocatalyst
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DOI：
10.1016/j.electacta.2020.137705
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发表时间：
2021-02
影响因子：
6.6
通讯作者：
A. Ohma;Yoshihisa Furuya;Tetsuya Mashio;Masashi Ito;K. Nomura;Tomohiko Nagao;H. Nishihara;H. Jinnai;T. Kyotani
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文献类型：
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作者：
A. Ohma;Yoshihisa Furuya;Tetsuya Mashio;Masashi Ito;K. Nomura;Tomohiko Nagao;H. Nishihara;H. Jinnai;T. Kyotani
具有海绵状介孔框架的石墨烯介孔海绵（GMS）被应用于聚合物电解质燃料电池的催化剂载体。制备负载铂的 GMS (Pt/GMS) 作为氧还原反应 (ORR) 测量的电催化剂，并与负载铂的科琴黑 (Pt/KB) 进行比较。通过旋转环盘电极 (RRDE) 方法评估 ORR 活性，分析过氧化氢 (H2O2) 的演化行为，作为 Pt 上离聚物覆盖的指标。结果发现，Pt/GMS 的 ORR 面积比活性比 Pt/KB 高 1.2 倍，且 H2O2 产量较低，这主要归因于 Pt/GMS 的离聚物覆盖率较低。通过透射电子显微断层扫描（3D-TEM）还观察到，Pt/GMS在其内含Pt纳米粒子的海绵状介孔框架之间具有大量孔隙。另一方面，Pt/KB 显示出更光滑的团聚体形状，其中 Pt 纳米颗粒主要位于 KB 团聚体内部。考虑到GMS的石墨烯和该体系中的水性电解质具有疏水性基底纳米表面的框架状介孔碳网络，得出的结论是，离聚物可以与其内部的疏水域形成自聚集，导致离聚物对GMS的纳米结构和GMS团聚物中的Pt纳米粒子的无效覆盖。
A graphene mesosponge (GMS), which has a sponge-like mesoporous framework, was applied to a catalyst support for polymer electrolyte fuel cell. Platinum loaded GMS (Pt/GMS) was prepared as electrocatalyst for oxygen reduction reaction (ORR) measurement and compared with platinum loaded Ketjen black (Pt/KB). ORR activity was evaluated by rotating ring disk electrode (RRDE) method to analyze hydrogen peroxide (H2O2) evolution behavior as an indicator of ionomer coverage on Pt. It was found that the ORR area specific activity of Pt/GMS was 1.2 times higher than that of Pt/KB with less H2O2yield, mainly attributed to the lower ionomer coverage at Pt/GMS. It was also observed by transmission electron microtomography (3D-TEM) that Pt/GMS has a lot of pores between the sponge-like mesoporous framework with Pt nanoparticles therein. On the other hand, Pt/KB showed smoother agglomerate shapes with Pt nanoparticles inside the KB agglomerates mainly. Considering the frame-like mesoporous carbon network having hydrophobic basal nanosurface of the graphene of GMS and the aqueous electrolyte in this system, it is concluded that the ionomer can form self-aggregation with its hydrophobic domain inside, resulting in ineffective coverage of the ionomer on the nanostructure of GMS and the Pt nanoparticles in the GMS agglomerates.