氮化钨-钨/掺氮有序介孔碳复合材料的制备及其氧还原性能

Preparation and Catalytic Activity for Oxygen Reduction Reaction of Tungsten Nitirde-Tungsten/Nitrogen Doped Ordered Mesoporous Carbon

采用软模板法制备了氮化钨-钨/掺氮有序介孔碳复合材料(WN-W/NOMC),作为一种高比表面积且价格低廉的阴极氧还原反应催化剂。通过适量添加尿素来改变复合材料中的氮含量,在掺氮量为7%(w/w)时,实验发现材料能够保持完整有序介孔结构,测试其比表面积高达835 m^2·g^(-1),透射电子显微镜(TEM)测试结果显示其催化颗粒均匀地分散在氮掺杂有序介孔碳载体上。在O_2饱和的0.1 mol·L^(-1 )KOH溶液中测试了材料的氧还原催化性能(ORR),显示其起始电位为0.87 V(vs RHE),极限电流密度为4.49 mA·cm^(-2),氧还原反应的转移电子数为3.4,接近于20%(w/w)商业Pt/C的3.8,说明该材料表现出近似4电子的氧还原反应途径。研究结果表明,WN-W/NOMC的催化性能虽然稍弱于商业铂碳(0.99 V,5.1 mA·cm^(-2)),但其具有远超铂碳的循环稳定性和耐甲醇毒化能力。

Tungsten nitride-Tungsten/nitrogen doped ordered mesoporous carbon(WN/W-NOMC),as a non-precious-metal cathode catalyst for oxygen reduction reaction(ORR),was successfully synthesized through a soft-template method.The amount of nitrogen was adjusted by urea,and when the content of nitrogen was 7%(w/w),the obtained composite had highly ordered mesoporous structure,and its specific surface area reached to 835 m2·g-1.Transmission electron microscope(TEM)shows that the catalytic particles were uniform supported on NOMC.ORR test was conducted in O2-staturated 0.1 mol·L-1 KOH solution,the oneset potential is 0.87 V(vs RHE)and the limiting current density is 4.49 mA·cm-2.The transfer number of electron was 3.4,which was close to commercial 20%(w/w)Pt/C(3.8),indicated that WN-NOMC exhibited an approximate 4e-transfer pathway during the ORR process.Though the catalytic activity is less than Pt/C,the excellent methanol tolerance and long-time electrochemical stability make WN-W/NOMC to be a potential electrode catalyst for ORR.