Comprehensive First Principles Approach to Understanding the Electrochemical Interface and Applications to Energy Problems

在分析和表面化学计划支持的这项研究中，将使用安德森实验室为研究电化学界面开发的新理论预测和分析电极表面上的催化反应机制。 在新能带理论程序的二维版本中，通过向电极添加电荷和在双层中添加反电荷来调节表面电势。 双电层的电荷分布是由一个修改后的泊松-玻尔兹曼理论在一个介电连续模型建模。 整个界面系统是不同的电荷自洽性，产生的吉布斯自由能的预测作为结构和电极电位的函数。 该理论，已经发现有用的预测可逆电位形成吸附在电极表面上的反应中间体作为潜在的功能，将扩展到表征过渡态结构和活化能在电极表面上的电子转移反应。 有效的能量转换和能量储存在未来将越来越多地依赖于以电功形式最佳利用化学反应的吉布斯能，而越来越少地依赖于以热和压力-体积功形式的化学反应的焓。 无论是生物系统中的酶还是燃料电池中的催化电极，都需要催化作用来直接从燃料中产生电能。 在分子结构和反应机理水平上理解电催化是至关重要的。 使用安德森实验室开发的理论实现这一目标的工作已经开始，该计划支持的研究将取得重大进展。 两个主要的推动力是（i）获得基本的理解，到目前为止，限制燃料电池中铂电催化剂的效率和稳定性的因素，（ii）应用所获得的洞察力，提出新的电催化剂，可能不包括铂，这是尚未发现的。 研究结果将有助于广泛的科学界，并应加速开发用于运输和移动的电子设备应用的高效便携式电源。

In this research supported by the Analytical and Surface Chemistry Program, catalytic reaction mechanisms on electrode surfaces will be predicted and analyzed using a new theory developed in the Anderson lab for studying electrochemical interfaces. In the two-dimensional version of the new band theory program, the surface potential is adjusted by adding charge to the electrode and counter charge in the double layer. The double layer charge distribution is modeled by a modified Poisson-Boltzmann theory within a dielectric continuum model. The whole interfacial system is varied to charge self-consistency, yielding predictions of the Gibbs free energies as functions of structure and electrode potential. The theory, already found useful for predicting reversible potentials for forming reaction intermediates adsorbed on electrode surfaces as functions of potential, will be extended to characterizing transition state structures and activation energies during electron transfer reactions on electrode surfaces. Efficient energy conversion and energy storage will in the future depend more and more on making the best use of the Gibbs energy of chemical reactions in the form of electrical work and less and less on the enthalpy of chemical reactions in the form of heat and pressure-volume work. Catalysis is required to generate electrical work directly from fuels, whether by enzymes in biological systems or catalytic electrodes in fuel cells. It is critical to develop an understanding of electrocatalysis at the level of molecular structures and reaction mechanisms. Work toward this goal using the theory developed in the Anderson lab has begun and the research supported by the program will yield significant advancements. Two major thrusts are (i) gaining fundamental understanding of the factors that so far limit the efficiency and stability of platinum electrocatalysts in fuel cells, (ii) applying the insight gained to proposing new electrocatalysts, possibly not including platinum, that are as yet undiscovered. The results will be helpful to a broad scientific community and should speed the development of efficient portable electric power sources for transportation and mobile electronic device applications.