Abstract

Density functional theory (DFT) (PBE) was used to simulate the breaking of C–H bond in methane on copper-enriched Ni–Cu clusters as the first step of dry reforming of methane. The models of catalysts were the nanoscale clusters NiCu₁₁S₆(PH₃)₈, NiCu₁₁S₆, NiCu₁₁O₆(PH₃)₈, and NiCu₁₁O₆. The binding energy of methane with the clusters was calculated, and the activation energy of the step CH₄* → \({\text{CH}}_{3}^{*}\) + H* was determined. It was found from the obtained data that the NiCu₁₁O₆ catalytic system is the most promising for CH₄ activation in terms of both kinetics (activation energy is 99 kJ/mol) and thermodynamics (energy change of the step is –29 kJ/mol). The coking resistance of the NiCu₁₁O₆ cluster was estimated by simulating the CH adsorption followed by dissociation (CH* → C* + H*). The calculated activation energy of this step is rather high: 159 kJ/mol.

中文翻译：

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甲烷中 Ni-Cu 氧化物和硫化物团簇 C-H 键活化的量子化学研究

摘要

密度泛函理论 (DFT) (PBE) 用于模拟富铜 Ni-Cu 团簇上甲烷中 C-H 键的断裂，作为甲烷干重整的第一步。催化剂模型为纳米级团簇NiC​​u ₁₁ S ₆ (PH ₃ ) ₈、NiCu ₁₁ S ₆、NiCu ₁₁ O ₆ (PH ₃ ) ₈和NiCu ₁₁ O ₆。_{计算甲烷与团簇的结合能，并计算步骤CH 4} * → \({\text{CH}}_{3}^{*}\)的活化能+ H* 被测定。从获得的数据发现，NiCu ₁₁ O ₆催化体系在动力学（活化能为99 kJ/mol）和热力学（步骤能量变化为–29 kJ/mol）方面最有希望用于CH _{4活化。NiCu 11} O ₆团簇的抗结焦性通过模拟CH吸附随后解离(CH*→C*+H*)来估计。该步骤的计算活化能相当高：159 kJ/mol。