Mavros Michael G, Tsuchimochi Takashi, Kowalczyk Tim, McIsaac Alexandra, Wang Lee-Ping, Voorhis Troy Van
Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 United States.
Inorg Chem. 2014 Jul 7;53(13):6386-97. doi: 10.1021/ic5002557. Epub 2014 Apr 2.
Water splitting by artificial catalysts is a critical process in the production of hydrogen gas as an alternative fuel. In this paper, we examine the essential role of theoretical calculations, with particular focus on density functional theory (DFT), in understanding the water-splitting reaction on these catalysts. First, we present an overview of DFT thermochemical calculations on water-splitting catalysts, addressing how these calculations are adapted to condensed phases and room temperature. We show how DFT-derived chemical descriptors of reactivity can be surprisingly good estimators for reactive trends in water-splitting catalysts. Using this concept, we recover trends for bulk catalysts using simple model complexes for at least the first-row transition-metal oxides. Then, using the CoPi cobalt oxide catalyst as a case study, we examine the usefulness of simulation for predicting the kinetics of water splitting. We demonstrate that the appropriate treatment of solvent effects is critical for computing accurate redox potentials with DFT, which, in turn, determine the rate-limiting steps and electrochemical overpotentials. Finally, we examine the ability of DFT to predict mechanism, using ruthenium complexes as a focal point for discussion. Our discussion is intended to provide an overview of the current strengths and weaknesses of the state-of-the-art DFT methodologies for condensed-phase molecular simulation involving transition metals and also to guide future experiments and computations toward the understanding and development of novel water-splitting catalysts.
通过人工催化剂进行水分解是生产作为替代燃料的氢气的关键过程。在本文中，我们研究了理论计算，特别是密度泛函理论（DFT），在理解这些催化剂上的水分解反应中的重要作用。首先，我们概述了关于水分解催化剂的DFT热化学计算，讨论了这些计算如何适用于凝聚相和室温。我们展示了DFT衍生的反应性化学描述符如何能够惊人地很好地估计水分解催化剂中的反应趋势。利用这一概念，我们使用简单的模型配合物至少对第一行过渡金属氧化物恢复了块状催化剂的趋势。然后，以CoPi氧化钴催化剂为例，我们研究了模拟在预测水分解动力学方面的有用性。我们证明，对溶剂效应进行适当处理对于用DFT计算准确的氧化还原电位至关重要，而氧化还原电位又决定了限速步骤和电化学过电位。最后，我们以钌配合物为讨论重点，研究了DFT预测机理的能力。我们的讨论旨在概述涉及过渡金属的凝聚相分子模拟的当前最先进DFT方法的优缺点，并指导未来的实验和计算，以理解和开发新型水分解催化剂。
