Materials Science Division, Argonne National Laboratory, Lemont, Illinois-60439, USA.
Nat Mater. 2012 May 6;11(6):550-7. doi: 10.1038/nmat3313.
Design and synthesis of materials for efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is of paramount importance in reducing energy losses in water-alkali electrolysers. Here, using 3d-M hydr(oxy)oxides, with distinct stoichiometries and morphologies in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) regions, we establish the overall catalytic activities for these reaction as a function of a more fundamental property, a descriptor, OH-M(2+δ) bond strength (0 ≤ δ ≤ 1.5). This relationship exhibits trends in reactivity (Mn < Fe < Co < Ni), which is governed by the strength of the OH-M(2+δ) energetic (Ni < Co < Fe < Mn). These trends are found to be independent of the source of the OH, either the supporting electrolyte (for the OER) or the water dissociation product (for the HER). The successful identification of these electrocatalytic trends provides the foundation for rational design of 'active sites' for practical alkaline HER and OER electrocatalysts.
设计和合成用于在碱性环境中高效电化学转化水为分子氢和氢氧根离子的材料，对于降低水电解槽的能量损失至关重要。在这里，我们使用 3d-M 氢（氧）氧化物，在析氢反应（HER）和析氧反应（OER）区域具有不同的化学计量和形态，将这些反应的整体催化活性作为一个更基本的性质，一个描述符，OH-M(2+δ)键强度（0 ≤ δ ≤ 1.5）的函数来建立。这种关系表现出反应性的趋势（Mn < Fe < Co < Ni），这是由 OH-M(2+δ)的能量强度决定的（Ni < Co < Fe < Mn）。这些趋势与 OH 的来源无关，无论是支持电解质（用于 OER）还是水离解产物（用于 HER）。这些电催化趋势的成功识别为合理设计实用碱性 HER 和 OER 电催化剂的“活性位点”提供了基础。
