Xiao B B, Zhu Y F, Lang X Y, Wen Z, Jiang Q
Key Laboratory of Automobile Materials, Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun 130022, China.
Sci Rep. 2014 Jun 6;4:5205. doi: 10.1038/srep05205.
To increase Pt utilization for oxygen reduction reaction (ORR) in fuel cells, reducing particle sizes of Pt is a valid way. However, poisoning or surface oxidation limits the smallest size of Pt particles at 2.6 nm with a low utility of 20%. Here, using density functional theory calculations, we develop a core-shell Al13@Pt42 cluster as a catalyst for ORR. Benefit from alloying with Al in this cluster, the covalent Pt-Al bonding effectively activates the Pt atoms at the edge sites, enabling its high utility up to 70%. Valuably, the adsorption energy of O is located at the optimal range with 0.0-0.4 eV weaker than Pt(111), while OH-poisoning does not observed. Moreover, ORR comes from O2 dissociation mechanism where the rate-limiting step is located at OH formation from O and H with a barrier of 0.59 eV, comparable with 0.50 eV of OH formation from O and H2O on Pt(111).
为提高燃料电池中氧还原反应（ORR）的铂利用率，减小铂颗粒尺寸是一种有效方法。然而，中毒或表面氧化将铂颗粒的最小尺寸限制在2.6 nm，利用率仅为20%，较低。在此，我们利用密度泛函理论计算，开发了一种核壳结构的Al13@Pt42团簇作为ORR催化剂。得益于该团簇中与铝的合金化，共价Pt-Al键有效地激活了边缘位点的铂原子，使其利用率高达70%。有价值的是，氧的吸附能处于最佳范围，比Pt(111)弱0.0-0.4 eV，且未观察到OH中毒现象。此外，ORR源于O2解离机制，其中限速步骤位于由O和H形成OH处，势垒为0.59 eV，与Pt(111)上由O和H2O形成OH的0.50 eV相当。
