Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA.
Nat Mater. 2022 Jul;21(7):804-810. doi: 10.1038/s41563-022-01221-5. Epub 2022 Apr 4.
The hydroxide exchange membrane fuel cell (HEMFC) is a promising energy conversion technology but is limited by the need for platinum group metal (PGM) electrocatalysts, especially for the hydrogen oxidation reaction (HOR). Here we report a Ni-based HOR catalyst that exhibits an electrochemical surface area-normalized exchange current density of 70 μA cm, the highest among PGM-free catalysts. The catalyst comprises Ni nanoparticles embedded in a nitrogen-doped carbon support. According to X-ray and ultraviolet photoelectron spectroscopy as well as H chemisorption data, the electronic interaction between the Ni nanoparticles and the support leads to balanced hydrogen and hydroxide binding energies, which are the likely origin of the catalyst's high activity. PGM-free HEMFCs employing this Ni-based HOR catalyst give a peak power density of 488 mW cm, up to 6.4 times higher than previous best-performing analogous HEMFCs. This work demonstrates the feasibility of efficient PGM-free HEMFCs.
氢氧化物交换膜燃料电池 (HEMFC) 是一种很有前途的能量转换技术，但受到对铂族金属 (PGM) 电催化剂的需求限制，特别是对氢氧化反应 (HOR)。在这里，我们报告了一种基于镍的 HOR 催化剂，其电化学表面积归一化交换电流密度为 70 μA·cm，在无 PGM 催化剂中是最高的。该催化剂由嵌入氮掺杂碳载体中的镍纳米颗粒组成。根据 X 射线和紫外光电子能谱以及 H 化学吸附数据，Ni 纳米颗粒与载体之间的电子相互作用导致氢和氢氧根的结合能达到平衡，这可能是该催化剂高活性的起源。使用这种基于镍的 HOR 催化剂的无 PGM HEMFC 的峰值功率密度达到 488 mW·cm，比以前性能最好的类似 HEMFC 高 6.4 倍。这项工作证明了高效无 PGM HEMFC 的可行性。
