作　　者： ; ; ; ;

机构地区： 中山大学物理科学与工程技术学院光电材料与技术国家重点实验室

出　　处： 《催化学报》 2009年第5期433-439,共7页

摘　　要： 通过交替微波法制备了PdxNi/C(x=1～4)催化剂,并对其形貌、结构及电化学性能进行了表征.结果表明,通过在Pd中掺杂Ni原子,其对氧还原反应(ORR)的催化活性较纯Pd的高.同时采用密度泛函理论(DFT)计算了一系列简化的团簇模型.计算结果表明,随着Ni的加入,纳米颗粒的最高占据轨道(HOMO)与最低空轨道(LUMO)能级增加,且两能级间隙(HLG)减小.因此在ORR中,一方面由于LUMO被抬高,降低了电子亲和能,带负电的催化剂颗粒更易将电子传递给O2,另一方面由于HLG减小,电中性颗粒HOMO上的电子也容易失去.这两方面的作用使其对O2还原活性得以增强.Fukui指数结合DFT方法和Mulliken布居分析指出,表面的Pd原子为催化剂团簇的活性中心. The PdxNi/C （x =1-4） catalysts were synthesized by an intermittent microwave method. The structure, morphology, and electrochemical performance were investigated. The results showed that the performance of the pure Pd for oxygen reduction reaction （ORR） could be improved by doping with Ni. The mechanism was studied by density functional theory （DFT） based on a serial of cluster models. The calculated results showed that the energy levels of HOMO and LUMO of the pure Pd nanoparticles were commonly uplifted by adding Ni atoms into them, and the energy gaps between the two orbitals were shortened. These changes made it easier for passing their electrons to O2 in ORR on PdxNi/C catalysts. The activity centers of cluster are Pd atoms on the surface according to the calculation of Fukui index, which combines with DFT results and Mulliken population analysis.

关 键 词： 钯 镍 氧还原 燃料电池 团簇模型 密度泛函理论

领　　域： [理学] [理学]