Asymmetric Volcano Trend in Oxygen Reduction Activity of Pt and Non-Pt Catalysts: In Situ Identification of the Site-Blocking Effect

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• 作者：Jingkun LiAmell Alsudairi ; Zi-Feng Ma ; Sanjeev Mukerjee ; Qingying Jia
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：February 1, 2017
• 年：2017
• 卷：139
• 期：4
• 页码：1384-1387
• 全文大小：332K
• ISSN：1520-5126

文摘

Proper understanding of the major limitations of current catalysts for oxygen reduction reaction (ORR) is essential for further advancement. Herein by studying representative Pt and non-Pt ORR catalysts with a wide range of redox potential (E_redox) via combined electrochemical, theoretical, and in situ spectroscopic methods, we demonstrate that the role of the site-blocking effect in limiting the ORR varies drastically depending on the E_redox of active sites; and the intrinsic activity of active sites with low E_redox have been markedly underestimated owing to the overlook of this effect. Accordingly, we establish a general asymmetric volcano trend in the ORR activity: the ORR of the catalysts on the overly high E_redox side of the volcano is limited by the intrinsic activity; whereas the ORR of the catalysts on the low E_redox side is limited by either the site-blocking effect and/or intrinsic activity depending on the E_redox.