摘要
燃料电池的阴极反应的反应动力学速率非常慢,限制了燃料电池技术的发展。因此,寻找低成本、高活性的氧还原催化剂具有重要的意义。多元金属核壳团簇表现出优良的氧还原活性。在本文中,以原子个数为19、38、55和79的八面体团簇作催化剂模型,采用密度泛函理论(GGA-PBE-PAW)方法,研究了一系列不同尺寸核壳Ni_(m)@M_(n-m)(n=19,38,55,79;m=1,6,13,19;M=Pt,Pd,Cu,Au,Ag)团簇催化剂的活性规律。优化^(*)O、^(*)OH和^(*)OOH吸附中间体结构,计算了吸附自由能和反应吉布斯自由能,以超电势为催化活性的描述符,研究了单原子Pt嵌入Ni_(m)@A_(un-m)团簇的活性规律。结果表明,Ni_(6)@Pt_(1)Au_(31)具有最好的ORR活性,并且Ni_(1)@Pt_(1)Au_(17)、Ni_(6)@Pt_(1)Au_(31)、Ni_(13)@Pt_(1)Au_(41)、Ni_(19)@Pt_(1)Au_(5)表现出比Pt38团簇以及Pt(111)表面更高的催化活性。Bader电荷和态密度分析表面,核壳之间的电荷转移以及单原子Pt嵌入Ni_(m)@A_(un-m)表面,改变了吸附位的电子性质,降低了^(*)OH的吸附强度,提高了ORR活性。单原子Pt嵌入Ni_(m)@A_(un-m)表面可能是一种合适的多元金属核壳ORR催化剂设计策略。
The slow kinetics of oxygen reduction reaction(ORR)limits the performance of low temperature fuel cells.Thus,it needs to design effective catalysts with low cost.Core-shell clusters(CSNCs)show promising activity because of their size-dependent geometric and electronic effects.The ORR activity trend of Ni_(m)@Pt_(1)Au_(n-m-1)(n=19,38,55,79;m=1,6,13,19)was studied using the GGA-PBE-PAW methods.The adsorption configurations of^(*)O,^(*)OH and^(*)OOH were optimized and the reaction free energies of four proton electron(H^(+)+e^(-))transfer steps were calculated.Using overpotential as a descriptor for the catalytic activity,Ni_(6)@Pt_(1)Au_(31) was found to be the most active ORR catalyst.Ni_(1)@Pt_(1)Au_(17),Ni_(13)@Pt_(1)Au_(41),and Ni_(19)@Pt_(1)Au_(5)9 had better activity than pure Pt clusters and Pt(111).Bader charge and DOS data indicate that the single Pt atom embedded on Ni_(m)@A_(un-m) can tune the electronic property of active site,and thus,significantly improve the activity.The present study showed that the single Pt atom embedded on Ni_(m)@A_(un-m) is a rational strategy to design effective core-shell ORR catalysts.
作者
李文杰
田东旭
杜红
燕希强
Wen-Jie Li;Dong-Xu Tian;Hong Du;Xi-Qiang Yan(State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China;Guangdong Key Laboratory for Hydrogen Energy Technologies,Foshan University,Foshan 528000,Guangdong,China)
出处
《电化学》
CAS
CSCD
北大核心
2021年第4期357-365,共9页
Journal of Electrochemistry
基金
supported by“the Fundamental Research Funds for the Central Universities”(DUT20ZD208)
Guangdong Key Laboratory for Hydrogen Energy Technologies(2018B030322005)。
关键词
核壳金属团簇
氧还原反应
密度泛函理论
超电势
单原子催化
core-shell metal clusters
oxygen reduction reaction
density functional theory
overpotential
single atom catalysis
