Reaction-diffusion (RD) coupling lies in the heart of chemical engineering. Due to the inherent density inhomogeneity of interfacial systems, the existing continuum approaches for quantifying the coupling between reaction and diffusion do not translate into interfacial systems, which highlights the urgent need for developing new methods to describe the RD coupling at nanoscale. In this work, a dynamic reaction density functional theory (DRxDFT) is proposed by combining the classical dynamic DFT for describing reactant/product diffusion with the reaction collision theory for addressing chemical reaction. For demonstrating its applicability to interfacial systems, the DRxDFT is hereafter applied to investigate an irreversible model reaction A + 2B → 2C on a catalytic substrate, and the effects of temperature, substrate adsorption strength, reactant concentration, diffusion coefficient, and reaction activation energy on reaction efficiency are examined. The calculated results show that the enhancement of reaction efficiency weakly depends on the unilateral increase of reaction or diffusion rate, but is strongly determined by the incensement of the coupled degree of reaction and diffusion. The proposed theory provides a promising tool for guiding the optimization and intensification of interfacial RD processes.

反应扩散（RD）耦合是化学工程的核心。由于界面系统固有的密​​度不均匀性，现有的用于量化反应和扩散之间耦合的连续谱方法不能转化为界面系统，这突出表明了迫切需要开发新的方法来描述纳米级的RD耦合。在这项工作中，通过将用于描述反应物/产物扩散的经典动态DFT与用于解决化学反应的反应碰撞理论相结合，提出了动态反应密度泛函理论（DRxDFT）。为了证明其在界面系统上的适用性，以下将DRxDFT用于研究催化基质上的不可逆模型反应A + 2B→2C，以及温度，基质吸附强度，检查反应物浓度，扩散系数和反应活化能对反应效率的影响。计算结果表明，反应效率的提高很少取决于反应或扩散速率的单方面增加，但强烈取决于反应和扩散的耦合程度。所提出的理论为指导界面RD过程的优化和强化提供了有希望的工具。