氮掺杂碳载钴催化剂制备及其TG-FTIR和XRD光谱分析

以三聚氰胺甲醛树脂预聚体为氮源、碳源,以乙酸钴为金属前驱体,制备氮掺杂碳载钴氧还原电催化剂。利用傅里叶变换红外光谱与热重联用(thermogravimetry-fourier transform infrared spectroscopy,TG-FTIR)、X射线衍射光谱分析(X-ray diffraction spectra,XRD)等研究了催化剂的制备过程和结构,采用旋转圆盘电极测试(rotating disc electrode,RDE)考察了制备过程中不同炭化温度对催化剂氧还原催化活性的影响。结果显示,在惰性气氛中,随炭化温度升高,样品中部分有机基团以CO,CO2,HCHO,NH3,NO2等形态随保护气流失,催化剂结构出现明显变化,形成典型的面心立方结构。旋转圆盘电极测试结果表明,所制备的催化剂都具有较好的电催化活性,氮掺杂碳载钴催化剂的氧还原起始电位在0.5V(vs.SCE)左右,炭化温度为700℃时制备的催化剂具有最高电催化氧还原活性。

TG-FTIR and XRD spectroscopic analysis for the preparation of nitrogen-doped carbon supported cobalt electrocatalysts

Nitrogen-doped carbon supported cobalt electrocatalysts for the reduction of oxygen were prepared from the high nitrogen content prepolymer of melamine formaldehyde resin and cobalt acetate. The preparation and structure of the electrocatalysts were investigated by TG-FTIR and XRD spectroscopic analysis methods. The electrochemical reduction of oxygen was studied at the nitrogen-doped carbon supported cobalt by using the rotating disk electrode method. The results indicated that the catalyst structure changed with the carbonization temperature under the protection of the inert gases. Some organic groups were decomposed into CO, CO2, HCHO, NH3 and NO2, which were taken away by the protecting gas. The electrocatalysts exhibited face-centered cubic structure. The RDE results showed that good electrocatalytic activity for oxygen reduction at these electrocatalysts was found under the experimental condition. The onset potential for oxygen reduction (E(onset)) was 0.5 V (vs. SCE). The catalyst prepared under 700 C was found to have the highest activity.