片状碳载金属纳米颗粒复合物的制备及其氧还原电活性

将双氰胺、蔗糖与酞菁铁(钴)的混合物通过简单热解法，制备出Co/C-N、Fe/C-N和Fe-Co/C-N纳米复合物。随后利用热还原法，将少量铂沉积于Co/C-N上得到片状碳负载的Co-Pt纳米颗粒Co-Pt/C-N。对样品进行了详细表征，并研究了其在全域pH范围内(酸性、中性与碱性溶液)中的氧还原反应(ORR)活性。结果表明，Co/C-N具有比Fe/C-N和Fe-Co/C-N更高的ORR起始电位和半波电位，并且在碱性和中性溶液中，Co/C-N表现出比Pt/C更强的ORR电活性；在酸性溶液中，铂负载量(质量分数)8.1%的Co-Pt/C-N表现出与Pt/C相近的ORR起始与半波电位。催化剂优异的电活性主要归因于片状碳形成的三维结构、金属纳米颗粒的均匀分布以及丰富的吡啶氮。

Preparation and oxygen reduction electroactivity of metal nanoparticles loaded on sheet-like carbon composites

Herein, Co/C-N, Fe/C-N, and Fe-Co/C-N nanocomposites were obtained by the self-template method, and high-temperature pyrolysis of the mixture composed of dicyandiamide, sucrose, and cobalt (ferric) phthalocyanine as nitrogen, carbon, and metal sources respectively. Then a small amount of platinum was deposited on the Co/C-N with better oxygen reduction reaction (ORR) electroactivity by thermal reduction to obtain carbon nanosheet-supported Co-Pt nanoparticles (Co-Pt/C-N). The catalysts were well characterized and tested for ORR. The Co/C-N catalyst displayed the onset potential (E_onset) and half-wave potential (E_1/2) of ORR closed to the Pt/C in an alkaline solution, and it even presented the more positive onset potential and half-wave potential in a neutral solution. For Co-Pt/C-N, its ORR electroactivity in an acidic solution was greatly enhanced compared with the Co/C-N and was comparable to the Pt/C. The excellent ORR electroactivity of the samples is mainly attributed to the 3D structure formed by the carbon nanosheets, uniform distribution of the metal nanoparticles, and abundant pyridine N.