科研之友
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摘要
Direct methanol fuel cells (DMFC) have attracted extensive attention as ideal candidates for automotive and portable applications owing to the fascinating advantages such as high conversion efficiency, environmental friendliness, safety, wide sources of methanol, and simple cell structure. Electrocatalysts are one of crucial factors limiting the performance of DMFC. Nowadays, precious Pt-based catalyst, in spite of costliness and scarcity, is the most popular catalyst for methanol oxidation reaction (MOR) at anode due to the much better performances than those of the non-Pt catalysts. But there exists some shortcomings such as poor CO-tolerance and durability. Pt alloying with other metals, e.g. Ru, is an effective strategy to improve the catalytic performance. In addition, the support with a large specific surface area (SSA), high conductivity and suitable porous structure, such as sp(2) carbon, could lead to high dispersion, high utilization and stability of Pt-based nanoparticles, also favorable for MOR. Recently, by in situ MgO template method, we reported the unique 3D hierarchical carbon-based nanocages featured with ultrahigh SSA, micro-meso-macro-pore coexistence, good conductivity and easy doping, which exhibited excellent electrochemical performances. Herein, taking the advantages of nitrogen-dopant anchoring function and unique mesostructures of hierarchical N-doped carbon nanocages (hNCNC), we report the Pt-Ru electrocatalysts immobilized on hNCNC (Pt-Ru/hNCNC) prepared via modified microwave-assisted ethylene glycol (EG) reduction method. The so-constructed Pt-Ru/hNCNC catalysts with ca. 30 wt% loading and tunable atomic ratio of Pt to Ru have a highly homogeneous dispersion of metal nanoparticles with the average size of ca. 3 nm. The alloying Pt-Ru/hNCNC catalysts demonstrate good CO-tolerance, high MOR activity and durability, superior to those of the counterparts of Pt/hNCNC and commercial PtRu/C. The good electrochemical performance can be ascribed to the synergistic effects of the bifunctional effect due to introduction of Ru, small size and high dispersion of metal nanoparticles induced by the large SSA and nitrogen participation of hNCNC, and multi-scaled hierarchical pore structures beneficial to the mass transportation. These results proposed a potential strategy to develop the high-performance Pt-based MOR catalysts based on the novel mesostructured hNCNC.
- 出版日期2016
- 单位南京大学
