Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche Université-CNRS 7591, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris Cedex 13, France;
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
Proc Natl Acad Sci U S A. 2017 Dec 19;114(51):13380-13384. doi: 10.1073/pnas.1711836114. Epub 2017 Sep 5.
Principles for designing self-healing water-splitting catalysts are presented together with a formal kinetics model to account for the key chemical steps needed for self-healing. Self-healing may be realized if the catalysts are able to self-assemble at applied potentials less than that needed for catalyst turnover. Solution pH provides a convenient handle for controlling the potential of these two processes, as demonstrated for the cobalt phosphate (CoP) water-splitting catalyst. For Co ion that appears in solution due to leaching from the catalyst during turnover, a quantitative description for the kinetics of the redeposition of the ion during the self-healing process has been derived. The model reveals that OER activity of CoP occurs with negligible film dissolution in neutral pH for typical cell geometries and buffer concentrations.
提出了设计自修复水分解催化剂的原则，并提出了一个正式的动力学模型来解释自修复所需的关键化学步骤。如果催化剂能够在低于催化剂转化所需的施加电势下自组装，则可以实现自修复。正如钴磷酸盐 (CoP) 水分解催化剂所示，溶液 pH 值为控制这两个过程的电势提供了一个方便的处理方法。对于由于催化剂在转化过程中浸出而出现在溶液中的 Co 离子，已经推导出了在自修复过程中离子重新沉积的动力学的定量描述。该模型表明，对于典型的电池几何形状和缓冲浓度，在中性 pH 值下，CoP 的 OER 活性几乎没有膜溶解。
