冷等离子体增强制备碳一化学催化剂的研究进展

Plasma-enhanced Preparation of Catalyst Used in C1 Chemistry

碳一化学对于缓解能源危机和环境问题具有重要意义,相关催化剂的研发一直是该领域的研究热点。等离子体在增强催化剂性能方面的优势得到了众多研究者的认可。综述了三种常见的冷等离子体——低气压辉光放电、介质阻挡放电、大气压等离子体射流,在增强制备碳一化学催化剂方面的研究进展。从目前的研究结果来看,等离子体制备的催化剂具有活性组分粒径小、分散度高、晶格缺陷少、金属-载体相互作用强等优势,因而在甲烷燃烧、甲烷重整、二氧化碳加氢等反应中具有更好的催化活性和抗积碳性。这主要得益于冷等离子体"低温高能"的特性:1)冷等离子体较低的温度不仅可以避免金属粒子烧结和团聚,还可以抑制金属粒子向载体内部扩散,增强金属-载体相互作用;2)冷等离子体中的高能电子能够吸附在金属粒子表面,使其带负电荷,彼此排斥,有利于提高金属粒子的分散度;3)冷等离子体中的高能粒子能够快速分解催化剂前驱体,金属粒子以低表面能的(111)晶面快速成核,晶格缺陷较少的(111)晶面能够减缓碳的生成速率。

C1 chemistry has important implications for relieving the energy crisis and environmental problems, and the re- search on related catalysts is a hotspot in this area. Plasma is proved to have advantages on the improvement of catalytic proper- ty and has been recognized by numerous researchers. The progress in plasma-enhanced preparation of catalyst used in CI che- mistry has been reviewed from three common cold plasmas, including： low-pressure glow discharge, dielectric barrier discharge and atmospheric pressure plasma jet. From the current study, the catalyst prepared via plasma has smaller particle size, higher dispersion, less lattice defects and stronger metal-support interaction, resulting in the better activity and anti-coking ability in CH4 combustion, CH4 reforming, CO2 hydrogenation reactions and so on. It is mainly ascribed to the property of＂higher energy with lower temperature＂ of plasma： 1） the lower temperature of cold plasma can not only inhibit the sintering and agglomeration of metal particles, but also restrain the diffusion of metal particles into support and enhance the metal-support interaction; 2） the electrons in plasma can be absorbed on the surface of metal particles to make the metal particles negatively charged to repel each other so as to improve the dispersion; 3） the high-energy particles in plasma can decompose the precursor quickly, make metal particles rapidly nucleate with （111） face as a result of its low surface energy. The （111） face with fewer lattice defects can suppress the formation rate of coking.