Liu Sihang, Vijay Sudarshan, Xu Mianle, Cao Ang, Prats Hector, Kastlunger Georg, Heenen Hendrik H, Govindarajan Nitish
Catalysis Theory Center, Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark.
Department of Chemical Engineering, University College London, Roberts Building, Torrington Place, London WC1E 7JE, United Kingdom.
J Chem Phys. 2023 Aug 28;159(8). doi: 10.1063/5.0157573.
Metal-water interfaces are central to understanding aqueous-phase heterogeneous catalytic processes. However, the explicit modeling of the interface is still challenging as it necessitates extensive sampling of the interfaces' degrees of freedom. Herein, we use ab initio molecular dynamics (AIMD) simulations to study the adsorption of furfural, a platform biomass chemical on several catalytically relevant metal-water interfaces (Pt, Rh, Pd, Cu, and Au) at low coverages. We find that furfural adsorption is destabilized on all the metal-water interfaces compared to the metal-gas interfaces considered in this work. This destabilization is a result of the energetic penalty associated with the displacement of water molecules near the surface upon adsorption of furfural, further evidenced by a linear correlation between solvation energy and the change in surface water coverage. To predict solvation energies without the need for computationally expensive AIMD simulations, we demonstrate OH binding energy as a good descriptor to estimate the solvation energies of furfural. Using microkinetic modeling, we further explain the origin of the activity for furfural hydrogenation on intrinsically strong-binding metals under aqueous conditions, i.e., the endothermic solvation energies for furfural adsorption prevent surface poisoning. Our work sheds light on the development of active aqueous-phase catalytic systems via rationally tuning the solvation energies of reaction intermediates.
金属-水界面对于理解水相多相催化过程至关重要。然而，对该界面进行精确建模仍然具有挑战性，因为这需要对界面的自由度进行大量采样。在此，我们使用从头算分子动力学（AIMD）模拟来研究糠醛（一种平台生物质化学品）在低覆盖率下于几种与催化相关的金属-水界面（Pt、Rh、Pd、Cu 和 Au）上的吸附情况。我们发现，与本工作中考虑的金属-气相界面相比，糠醛在所有金属-水界面上的吸附稳定性都较差。这种稳定性降低是由于糠醛吸附时表面附近水分子位移所带来的能量惩罚导致的，溶剂化能与表面水覆盖率变化之间的线性相关性进一步证明了这一点。为了在无需进行计算成本高昂的AIMD模拟的情况下预测溶剂化能，我们证明了OH结合能是估算糠醛溶剂化能的良好描述符。通过微动力学建模，我们进一步解释了在水相条件下糠醛在本质上强结合金属上氢化活性的来源，即糠醛吸附的吸热溶剂化能可防止表面中毒。我们的工作通过合理调节反应中间体的溶剂化能，为开发活性水相催化体系提供了思路。
