Measuring Single Ion Gibbs Transfer Energies without Extrathermodynamic Assumptions to Validate the Unified Acidity and Redox Scales within the Protoelectric Potential Map PPM

在没有热力学假设的情况下测量单离子吉布斯转移能量，以验证质子电势图 PPM 内的统一酸度和氧化还原尺度

• 批准号: 420771175
• 负责人: Professor Dr. Ingo Krossing
• 金额: --
• 依托单位: Institut für Anorganische und Analytische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/420771175?language=en
• 关键词: Measuring; Single; Ion; Gibbs; Transfer

pH values and redox potentials are common knowledge and of utmost importance, e.g. to analytical chemistry, energy storage and conversion (electrolysis, fuel cells, batteries), material sciences (corrosion, metallization) or life sciences (proton pump, proton coupled electron transfer, photosystem). Their definitions, e.g. pH = −log a(H+), base on thermodynamic quantities of single ions. Although used worldwide, single ion quantities are fundamentally questioned for electroneutrality reasons. A major missing link in the existing theoretical framework of solution thermodynamics was the comparability of these thermodynamic quantities in and between all media. This is now possible by using the unified acidity and redox scales pHabs and peabs introduced by our group. However, now the experimental determination of single ion Gibbs transfer energies of corresponding redox/acid-base systems is the unresolved problem. So far, heavily discussed extrathermodynamic assumptions have to be used for this purpose, which are associated with uncertainties of at least 1 – 2 pH- / pe-units (60 – 120 mV, in some cases up to 1 V).Our core objective, therefore, is the determination of single ion Gibbs transfer energies in a strict thermodynamic sense by means of potential measurements between two half cells containing different solvents. They are connected – and this is new and crucial – by an “ideal” salt bridge, filled with a specific ionic liquid with identical diffusion coefficients of anion and cation. In this set up, the largest parts of the liquid junction potential occurring at interfaces between two different media cancel. The remaining parts can then be determined without extrathermodynamic assumptions and the measured cell potential can be directly assigned to the Gibbs energy of transfer of single ions. This would provide the last missing link for solution thermodynamics, including acceptance of single ion quantities.

pH值和氧化还原电位是公知常识，对分析化学、能量储存和转换（电解、燃料电池、电池）、材料科学（腐蚀、金属化）或生命科学（质子泵、质子耦合电子转移、光系统）等至关重要。它们的定义，例如pH = −log a（H+），是基于单离子的热力学量。虽然在世界范围内使用，但由于电中性的原因，单离子量从根本上受到质疑。在现有的溶液热力学理论框架中，一个主要的缺失环节是这些热力学量在所有介质中和介质之间的可比性。现在，通过使用我们小组引入的统一酸度和氧化还原标度pHabs和peabs，这是可能的。然而，目前实验测定相应的氧化还原/酸碱体系的单离子吉布斯转移能是一个尚未解决的问题。到目前为止，大量讨论的超热力学假设必须用于此目的，其与至少1 - 2个pH- /pe-单位的不确定性相关（60 - 120 mV，在某些情况下高达1 V）。因此，我们的核心目标是，是在严格的热力学意义上，通过两个半电池之间的电势测量来确定单离子吉布斯转移能，溶剂.它们通过一个“理想”盐桥连接起来--这是新的和关键的--盐桥充满了一种特定的离子液体，具有相同的阴离子和阳离子扩散系数。在这种设置中，在两种不同介质之间的界面处发生的液体接界电势的最大部分被抵消。剩余的部分，然后可以确定没有extrathermodynamic假设和测得的细胞电位可以直接分配给吉布斯转移的单离子的能量。这将为溶液热力学提供最后一个缺失的环节，包括接受单离子量。