Sakti Aditya W, Chou Chien-Pin, Nakai Hiromi
Element Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyotodaigaku-Katsura, Kyoto 615-8520, Japan.
Waseda Research Institute for Science and Engineering (WISE), Waseda University, Tokyo 169-8555, Japan.
ACS Omega. 2020 Mar 18;5(12):6862-6871. doi: 10.1021/acsomega.0c00203. eCollection 2020 Mar 31.
Carbonaceous or oxy-carbon species are intermediates formed during C H combustion on a Pt /AlO catalyst, which contain carbon, hydrogen, and oxygen atoms. The accumulation of the carbonaceous species, arguably, leads to catalytic deactivation; therefore, their removal is of importance. As the diffusion process is occasionally the rate-determining step in the growth of carbonaceous species, the present study aims to reveal the diffusion mechanisms. The free energy barriers of acetate, formate, and methoxy diffusion on the (100)-γ-AlO surface were evaluated through extensive metadynamics simulations at the density-functional tight-binding level. The present work deduces that each adopted carbonaceous species exhibits different diffusion mechanisms and supports experimental evidence that the acetate species exhibits the slowest diffusivity among the adopted carbonaceous species.
含碳或碳氧物种是在Pt/AlO催化剂上CH燃烧过程中形成的中间体，它们含有碳、氢和氧原子。可以说，含碳物种的积累会导致催化失活；因此，去除这些物种很重要。由于扩散过程有时是含碳物种生长的速率决定步骤，本研究旨在揭示扩散机制。通过在密度泛函紧束缚水平上进行广泛的元动力学模拟，评估了乙酸根、甲酸根和甲氧基在(100)-γ-AlO表面上的自由能垒。本研究推断，每种采用的含碳物种都表现出不同的扩散机制，并支持实验证据，即在采用的含碳物种中，乙酸根物种的扩散率最慢。
