Cheng Han, Liu Si, Hao Zikai, Wang Jingyu, Liu Bojun, Liu Guangyao, Wu Xiaojun, Chu Wangsheng, Wu Changzheng, Xie Yi
Hefei National Laboratory for Physical Science at the Microscale , iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) , CAS Key Laboratory of Mechanical Behavior and Design of Materials , University of Science and Technology of China , Hefei , Anhui 230026 , P. R. China . Email:
CAS Key Laboratory of Materials for Energy Conversion , Department of Material Science and Engineering , University of Science and Technology of China , Hefei , Anhui 230026 , P. R. China.
Chem Sci. 2019 May 8;10(21):5589-5595. doi: 10.1039/c9sc01078e. eCollection 2019 Jun 7.
In this study, we report that optimal coordination-site exposure engineering in porous platinum brings ultrahigh activity and durability for the fuel cell oxygen reduction reaction (ORR). The porous platinum with numerous grain boundaries (GBP-Pt) consisting of 3 nm crystals exhibits 7 times higher ORR activity than commercial Pt. For fuel-cell measurements, the GBP-Pt catalyst based MEA exhibits high power density (1.49 W cm, 0.71 A mg Pt for mass activity) and stability (12.9% loss after 30 K cycles), all of which far surpass the U.S. DOE target in 2020 (0.44 A mg Pt for mass activity and 40% loss for stability). Density Functional Theory (DFT) calculation and X-ray Absorption Fine Structure (XAFS) results suggest that proper Pt coordination site exposure in grain boundaries provides optimal adsorption energies for oxygen species and high stability in the ORR, even superior to Pt(111) sites. We anticipated that coordination-site exposure engineering would open a new avenue to offer robust electrocatalysts for the fuel-cell oxygen reduction reaction.
在本研究中，我们报道了多孔铂中最佳配位位点暴露工程为燃料电池氧还原反应（ORR）带来了超高活性和耐久性。由3纳米晶体组成的具有大量晶界的多孔铂（GBP-Pt）表现出比商业铂高7倍的ORR活性。对于燃料电池测量，基于GBP-Pt催化剂的MEA表现出高功率密度（1.49 W/cm²，质量活性为0.71 A/mg Pt）和稳定性（30 K循环后损失12.9%），所有这些都远远超过了美国能源部2020年的目标（质量活性为0.44 A/mg Pt，稳定性损失40%）。密度泛函理论（DFT）计算和X射线吸收精细结构（XAFS）结果表明，晶界中适当的铂配位位点暴露为氧物种提供了最佳吸附能，并在ORR中具有高稳定性，甚至优于Pt(111)位点。我们预计，配位位点暴露工程将为燃料电池氧还原反应提供强大的电催化剂开辟一条新途径。
