有序介孔氮掺杂碳负载三氧化二铁的制备及其催化氧还原性能

Preparation of Ordered Mesoporous Nitrogen Doped Carbon Supported Fe2O3 for Oxygen Reduction Reaction

制备了有序介孔氮掺杂碳负载三氧化铁,有效降低了氧还原的过电势。通过扫描电子显微镜、透射电子显微镜、氮气吸附-脱附测试、粉末X射线衍射、X射线光电子能谱、拉曼光谱等技术表征了所制备的催化剂的物理化学性质。此外,用旋转圆盘电极测试了其在碱性条件下对氧还原反应的催化活性和选择性。实验结果表明:氮气热解后铁以三氧化二铁的形式负载于有序介孔氮掺杂碳中,其比表面积达到755 cm^2·g^-1。拉曼和X射线光电子能谱结果表明,加入铁前驱体后所制备的催化剂石墨化程度有所提升、阻抗降低、导电性增加。在碱性条件下,Fe2O3@NC催化剂呈现出4电子氧还原反应,其起始电位(-0.01 V vs Ag/AgCl)和半波电位(-0.13 V vs Ag/AgCl)与商用20%Pt/C相当。此外,该催化剂具有较好的抗甲醇性能且其恒电压稳定性优于商用Pt/C。Fe2O3@NC催化剂用于锌-空电池放电测试,其放电功率可以达到88 mW·cm^-2,是商用Pt/C的1.29倍。

Ordered mesoporous nitrogen doped carbon supported iron oxide was prepared,which effectively reduced the overpotential of oxygen reduction.The physicochemical properties of the as‑prepared catalysts were characterized by scanning electron microscopy,transmission electron microscopy,nitrogen adsorption‑desorption test,powder X‑ray diffraction,X‑ray photoelectron spectroscopy and Raman spectroscopy.In addition,the activity and selectivity for oxygen reduction reaction was tested by rotating disc electrode under alkaline conditions.The results show that iron was loaded in ordered mesoporous nitrogen doped carbon in the form of Fe2O3 after nitrogen pyrolysis,and its specific surface area reached 755 cm^2·g^-1.The results of Raman and X‑ray photoelectron spectroscopy show that the graphitization degree of the catalyst increased with adding iron precursor.The impedance was decreased and its conductivity was increased.Under alkaline conditions,Fe2O3@NC exhibited a 4‑electron oxygen reduction reaction,and its initial potential(-0.01 V vs Ag/AgCl)and half slope potential(-0.13 V vs Ag/AgCl)were comparable to those of commercial 20%Pt/C.In addition,the catalyst had superior methanol resistance and excellent constant voltage stability compared with commercial Pt/C.The discharge power of Fe2O3@NC reached 88 mW·cm^-2,which was 1.29 times that of commercial Pt/C.