以氧化石墨烯(GO)为碳载体,g-C3N4作为N源,Co(NO3)2·6H2O作为Co源,经热处理后构建了新型Co/N/C结构的氧气还原催化剂。在热处理过程中,氧化石墨烯上的官能团分解脱离形成活性中心,与结构相似的gC3N4相互作用并通过配位作用实现了Co元素和N元素的同时掺杂。使用傅立叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)对其进行结构表征证实了N元素和Co元素的成功掺杂。在催化剂中N元素主要是以腈氮、石墨式氮、吡啶式氮的形式存在,Co元素则与其中的吡啶式氮配位形成Co-Nx结构。采用循环伏安法(CV)和旋转圆盘电极(RDE)技术,研究其在碱性介质中对氧气还原反应(ORR)的电催化性能。实验结果显示,该新型Co/N/C催化剂具有良好的ORR电催化活性,在碱性溶液中的起始电位为-0.06V,同时有着良好的稳定性和抗甲醇性能。
The Co/N/C catalyst for ORR was prepared by using graphene oxide as carbon support, g-Cs N4 as nitro- gen source and Co(NO3 )2 ? 6H20 as cobalt source. The precursors were then treated thermally at 800℃ under nitrogen at- mosphere. In the process of heat treatment, the functional groups of graphene oxide were decomposed to form active cen- ter. Simultaneous doping of N and Co can be realized by the interaction between graphene oxide and g-C3 N4. The non no- ble-metal catalyst was further characterized by fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It was showed that N and Co elements were successively doped into the graphene substrate. In the catalyst, N elements existed mainly in the forms of Nitrile N,pyridine N and graphite N. Co(II) and Co(III) were coordi- nated with pyridine N to form Co-Nx structure. The electrocatalytic activity of catalyst was evaluated by cyclic voltamme try (CV) and rotating disk electrode (RDE) experiments. The catalyst showed high electrocatalytic activity toward ORR in an alkaline solution with an onset potential of --0.06 V vs. Ag/AgC1 reference electrode.Good stability and methanol-- tolerant ability of the catalyst were also observed.