Sun Jikai, Wu Jianzhong
Department of Chemical and Environmental Engineering, University of California Riverside CA 92521 USA
Chem Sci. 2025 Sep 17. doi: 10.1039/d5sc03726c.
Conventional methods for modeling thermocatalytic systems are typically based on the Kohn-Sham density functional theory (KS-DFT), neglecting the inhomogeneous distributions of gas molecules in the reactive environment. However, industrial reactions often take place at high temperature and pressure, where the local densities of gas molecules near the catalyst surface can reach hundreds of times their bulk values. To assess the environmental impacts on surface composition and reaction kinetics, we integrate KS-DFT calculations for predicting surface bonding energy with classical DFT to evaluate gas distribution and the grand potential of the entire reactive system. This multiscale approach accounts for both bond formation and non-bonded interactions of gas molecules with the catalyst surface and reveals that the surface composition is determined not only by chemisorption but also by the accessibility of surface sites and their interactions with the surrounding molecules in the gas phase. This theoretical procedure was employed to establish the relationship between surface coverage, gas-phase composition, and bulk phase thermodynamic conditions with thermocatalytic hydrogenation of CO as a benchmark. The computational framework opens new avenues for studying adsorption and coverage on catalytic surfaces under industrially relevant conditions.
传统的热催化系统建模方法通常基于科恩-沈密度泛函理论（KS-DFT），忽略了反应环境中气体分子的非均匀分布。然而，工业反应通常在高温高压下进行，此时催化剂表面附近气体分子的局部密度可达其体相值的数百倍。为了评估环境对表面组成和反应动力学的影响，我们将用于预测表面键能的KS-DFT计算与经典DFT相结合，以评估气体分布和整个反应系统的巨势。这种多尺度方法考虑了气体分子与催化剂表面的键形成和非键相互作用，揭示了表面组成不仅由化学吸附决定，还由表面位点的可及性及其与气相中周围分子的相互作用决定。以CO的热催化加氢为基准，采用该理论程序建立了表面覆盖率、气相组成和体相热力学条件之间的关系。该计算框架为研究工业相关条件下催化表面的吸附和覆盖率开辟了新途径。
