First-principles kinetic modeling for solar hydrogen production

在界面处开发可持续和高效的能量转换过程是基础能源科学快速发展领域的核心。如何成功地解决这一挑战最终将取决于获得的分子水平理解程度。在这方面，与多相催化中相应的热过程相比，电或光催化转化的严重知识差距是惊人的。这种差异在预测质量的现状中最为明显，即在这两个领域中基于第一性原理的建模，这在很大程度上归因于与处理电化学环境和描述由光激发电荷或外部电位驱动的表面氧化还原化学有关的多因素方法问题。成功解决这些复杂问题将把电催化的建模方法提升到与多相催化相似的水平，其影响甚至可能取代过去十年中所看到的。相应的方法开发是本提案的核心目标，特别强调数值有效的方法，最终将允许达到全面的微动力学公式。协同结合两个参与小组的方法学专业知识，我们特别致力于实现和推进隐式和混合隐式/显式溶剂化模型，以及描述固液界面能量相关过程的QM/MM方法。有了明确的目标，以开发通用的方法，我们将说明他们的使用与应用，通过水分解制氢。解开电离层。这既涉及Pt等金属电极上的析氢反应，也涉及TiO2等氧化物光催化剂上的直接水裂解反应。通过这一点，我们期望得到详细的机制理解，最终形成光或电位驱动的氧化还原过程的综合微动力学模型。用动力学蒙特卡罗模拟对这些模型进行评估，将明确地确定决定速率和产生过电位的步骤，从而为整个过程的合理优化提供基础。因此，我们的研究将提供一个关键的例子，说明基础能源科学计算方法的系统方法发展如何导致突破性进展，并为基础理解和前沿应用服务。

The development of sustainable and efficient energy conversion processes at interfaces is at the center of the rapidly growing field of basic energy science. How successful this challenge can be addressed will ultimately depend on the acquired degree of molecular-level understanding. In this respect, the severe knowledge gap in electro- or photocatalytic conversions compared to corresponding thermal processes in heterogeneous catalysis is staggering. This discrepancy is most blatant in the present status of predictive-quality, viz. first-principles based modelling in the two fields, which largely owes to multifactorial methodological issues connected with the treatment of the electrochemical environment and the description of the surface redox chemistry driven by the photo-excited charges or external potentials.Successfully tackling these complexities will advance modelling methodology in (photo)electrocatalysis to a similar level as already established in heterogeneous catalysis, with an impact that likely even supersedes the one seen there in the last decade. A corresponding method development is the core objective of the present proposal, with particular emphasis on numerically efficient approaches that will ultimately allow to reach comprehensive microkinetic formulations. Synergistically combining the methodological expertise of the two participating groups we specifically aim to implement and advance implicit and mixed implicit/explicit solvation models, as well as QM/MM approaches to describe energy-related processes at solid-liquid interfaces. With the clear objective to develop general-purpose methodology we will illustrate their use with applications to hydrogen generation through water splitting. Disentangling the electro- resp. photocatalytic effect with respect to the corresponding dark reaction, this concerns both the hydrogen evolution reaction at metal electrodes like Pt and direct water splitting at oxide photocatalysts like TiO2. Through this we expect to arrive at a detailed mechanistic understanding that will culminate in the formulation of comprehensive microkinetic models of the light- or potential-driven redox process. Evaluating these models with kinetic Monte Carlo simulations will unambiguously identify the rate-determining and overpotential-creating steps and therewith provide the basis for a rational optimization of the overall process. As such our study will provide a key example of how systematic method development in computational approaches to basic energy sciences leads to breakthrough progress and serves both fundamental understanding and cutting-edge application.