Tetteh Emmanuel Batsa, Gyan-Barimah Caleb, Lee Ha-Young, Kang Tong-Hyun, Kang Seonghyeon, Ringe Stefan, Yu Jong-Sung
Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Republic of Korea.
Analytical Chemistry─Center for Electrochemical Sciences (CES), Faculty for Chemistry and Biochemistry, Ruhr University Bochum, Bochum 44780, Germany.
ACS Appl Mater Interfaces. 2022 Jun 8;14(22):25246-25256. doi: 10.1021/acsami.2c00398. Epub 2022 May 24.
Over the last years, the development of highly active and durable Pt-based electrocatalysts has been identified as the main target for a large-scale industrial application of fuel cells. In this work, we make a significant step ahead in this direction by preparing a high-performance electrocatalyst and suggesting new structure-activity design concepts which could shape the future of oxygen reduction reaction (ORR) catalyst design. For this, we present a new one-dimensional nanowire catalyst consisting of a L1 ordered intermetallic PtCo alloy core and compressively strained high-index facets in the Pt-rich shell. We find the nanoscale PtCo catalyst to provide an excellent turnover for the ORR and hydrogen evolution reaction (HER), which we explain from high-resolution transmission electron microscopy and density functional theory calculations to be due to the high ratio of Pt(221) facets. These facets include highly active ORR and HER sites surprisingly on the terraces which are activated by a combination of sub-surface Co-induced high Miller index-related strain and oxygen coverage on the step sites. The low dimensionality of the catalyst provides a cost-efficient use of Pt. In addition, the high catalytic activity and durability are found during both half-cell and proton exchange membrane fuel cell (PEMFC) operations for both ORR and HER. We believe the revealed design concepts for generating active sites on the Pt-based catalyst can open up a new pathway toward the development of high-performance cathode catalysts for PEMFCs and other catalytic systems.
在过去几年中，开发高活性和耐用的铂基电催化剂已被确定为燃料电池大规模工业应用的主要目标。在这项工作中，我们朝着这个方向迈出了重要一步，制备了一种高性能电催化剂，并提出了新的结构-活性设计概念，这些概念可能会塑造氧还原反应（ORR）催化剂设计的未来。为此，我们展示了一种新型一维纳米线催化剂，它由L1有序金属间PtCo合金核和富含铂的壳层中的压缩应变高指数晶面组成。我们发现这种纳米级PtCo催化剂对ORR和析氢反应（HER）具有优异的周转性能，我们通过高分辨率透射电子显微镜和密度泛函理论计算解释，这是由于Pt(221)晶面的比例很高。这些晶面在台面上意外地包含高活性的ORR和HER位点，这些位点通过次表面Co诱导的高米勒指数相关应变和台阶位点上的氧覆盖的组合而被激活。催化剂的低维度提供了铂的经济有效利用。此外，在ORR和HER的半电池和质子交换膜燃料电池（PEMFC）操作中都发现了高催化活性和耐久性。我们相信，在铂基催化剂上产生活性位点所揭示的设计概念可以为开发用于PEMFC和其他催化系统的高性能阴极催化剂开辟一条新途径。
