Mo掺杂W18O49复合材料作为氧还原催化剂载体的研究

摘要

以具有氧缺陷的W18O49为前驱体,掺杂不同比例的M o,制备得到系列M o—W18O49催化剂.通过X射线衍射、透射电镜、X射线光电子能谱手段表征材料的形貌结构及化学组成,通过循环伏安、线性扫描伏安法测试系列M o—W18O49材料的氧还原催化性能,结果表明:当M o的掺杂量为30% 时,氧还原活性最高.在此基础上,再在30% M o—W18O49材料上负载少量的Pt(质量分数为10%),制备得到Pt/30% M o—W18O49,并在酸性介质中进行氧还原性能测试,发现制备的 Pt/30% M o—W18O49催化剂的活性和稳定性优于商用Pt/C.材料的物性表征显示M o的掺杂使材料引入了氧缺陷.氧缺陷的存在可以促进O—O键的断裂,是提高性能的一个重要因素;Pt与30%M o—W18O49载体间的强相互作用是该材料具有较高催化性能的另一个重要因素.%The electrocatalysts for oxygen reduction reaction(ORR)are successfully prepared with different Mo doping rations by using precursor W18O49which consists of oxygen defects. The morphology,structure and chemical composition of the Mo —W18O49electrocatalysts are characterized by X-ray diffraction, High resolution transmission electron microscopy and X-ray photoelectron spectroscopy.The ORR catalytic performance is characterized by electrochemical measurements,such as cyclic voltammetry,linear sweep voltammetry etc.The results showed among series of Mo —W18O49 catalysts,the one with 30% doped Mo had the better catalytic activity for ORR than the others.T hen, a small amount of Pt(w = 10%)was loaded on the 30% Mo—W18O49support.The catalytic performance of synthesized Pt/30% Mo—W18O49catalyst for oxygen reduction in acidic medium was tested.It was found that the catalytic activity and stability of Pt/30% Mo—W18O49was superior to the 20% commercial Pt/C.The results showed that the doping of Mo induced oxygen defects in Mo—W18O49catalysts,which promoted the cleavage of O—O and became an important key for the excellent catalytic performance.The strong interaction between Pt and 30% Mo—W18O49 support is another important factor to enhance the catalytic performance of catalyst for oxygen reduction.