Abstract:

Carbon dioxide and methane are the main greenhouse gases, and their conversion and utilization could contribute to the realization of “dual carbon” target. CH₄/CO₂ conversion via plasma method gets both gas and liquid products, giving the target product low selectivity. Plasma combined with catalysts can effectively improve the selectivity of target product. In this work, active metals of Ni, Fe, and Cu are loaded on γ-Al₂O₃ by micro-combustion method, and their reaction performance for CH₄/CO₂ conversion is significantly improved in combination with plasma. Metal loading changes the oxygen vacancy ratio of the catalyst and strengths the intensity of basic sites, which boosts CO₂ conversion. The weak acid of the metal catalyst enhances the liquid product selectivity, such as Lewis acid benefits the conversion to alcohol products, while Brønsted acid promotes the generation of acetic acid. Metal catalysts enhance the dielectric barrier discharge power, transfer more charge and increase the reaction energy efficiency. This study reveals the influence of catalyst structure on product selectivity and is conducive to the rational design of catalysts for plasma catalysis.

Key words: plasma, catalyst, dielectric barrier discharge, carbon dioxide, methane

摘要：

二氧化碳和甲烷是大气中主要的温室气体，两者的高效资源化利用有助于实现双碳目标。等离子体催化CH₄/CO₂气液两相均有产物，但存在产物组成复杂、选择性低的问题。等离子体与催化剂结合可以有效提高目标产物选择性，本文采用微燃烧法将活性金属负载在载体γ-Al₂O₃上，与等离子体结合催化转化CH₄/CO₂。负载金属后催化剂氧空位比例的改变增强催化剂表面碱性，进而提高CO₂转化率。负载金属后弱酸比例增加，有利于合成液相产物，其中Lewis酸有利于合成醇类产物，而Brønsted酸促进了乙酸合成。金属催化剂装填增强了介质阻挡放电功率，转移更多电荷，提升了反应能量效率。通过催化剂结构对产物选择性的影响规律研究，有利于针对等离子体催化进行催化剂的理性设计。

关键词: 等离子体, 催化剂, 介质阻挡放电, 二氧化碳, 甲烷