Mo掺杂W_(18)O_(49)复合材料作为氧还原催化剂载体的研究

Research on a electrocatalyst support of Mo doped W_(18)O_(49) for oxygen reduction reaction

以具有氧缺陷的W_(18)O_(49)为前驱体,掺杂不同比例的Mo,制备得到系列Mo—W_(18)O_(49)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Mo—W_(18)O_(49)材料的氧还原催化性能,结果表明:当Mo的掺杂量为30%时,氧还原活性最高.在此基础上,再在30%Mo—W_(18)O_(49)材料上负载少量的Pt(质量分数为10%),制备得到Pt/30%Mo—W_(18)O_(49),并在酸性介质中进行氧还原性能测试,发现制备的Pt/30%Mo—W_(18)O_(49)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Mo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%Mo—W_(18)O_(49)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-W18O49catalysts,the one with 30%doped Mo had the better catalytic activity for ORR than the others.Then,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-W18O49support is another important factor to enhance the catalytic performance of catalyst for oxygen reduction.