欢迎访问《环境科学学报》编辑部网站！

快速检索			高级检索

研究报告

刘欢,王樱,陈铭,叶代启,陈礼敏.Co负载量对Co/TiZrO₄催化CO₂氧化乙烷脱氢制乙烯反应性能的影响[J].环境科学学报,2023,43(2):433-446

Effects of Co loading on the performance of Co/TiZrO₄ catalysts for CO₂ oxidative ethane dehydrogenation to ethylene

叶代启
华南理工大学环境与能源学院，广州 510006;挥发性有机物污染治理技术与装备国家工程实验室，广州 510006;广东省大气环境与污染控制重点实验室，广州 510006

陈礼敏
华南理工大学环境与能源学院，广州 510006;挥发性有机物污染治理技术与装备国家工程实验室，广州 510006;广东省大气环境与污染控制重点实验室，广州 510006

摘要：Co基催化剂在低碳烷烃直接脱氢及氧化脱氢制烯烃方面表现出良好的应用潜力.为了探究Co物种的价态对CO₂氧化乙烷脱氢制乙烯的影响，以共沉淀法制备的TiZrO₄固溶体为载体，采用浸渍法制备了一系列X%Co/TiZrO₄（X=0.5、1、3、5和7.5）催化剂.结果表明，0.5%Co/TiZrO₄和1%Co/TiZrO₄催化剂的催化活性较差，但保持了相当高的C₂H₄选择性（>90%）和碳平衡（≈100%）；3%Co/TiZrO₄催化剂在反应过程中表现出良好的C₂H₆和CO₂活化能力，在650 ℃、质量空速WHSV=9000 mL?g^-1?h^-1的反应条件下获得了约25%的乙烯收率；而5% Co/TiZrO₄和7.5%Co/TiZrO₄催化剂则在600 ℃及以上温度反应时乙烯选择性明显下降并伴随严重的积碳.SEM、XRD、Raman、UV-vis、XPS、H₂-TPR和in-situ Raman等研究表明，Co²⁺-TiZrO₄存在金属-载体强相互作用，在反应中具有良好的C₂H₄选择性，适量的Co⁰有助于CO₂和C₂H₆的活化，但大量聚集的Co⁰会促进干重整和积碳反应，使催化剂严重积碳导致失活.

Abstract：Co-based catalysts exhibit great potential in direct dehydrogenation and oxidative dehydrogenation of light alkanes to alkenes. In order to elucidate the effects of the valence state of Co on the catalytic performance of CO₂ oxidative ethane dehydrogenation to ethylene， a series of X%Co/TiZrO₄ （X=0.5， 1， 3， 5 and 7.5） catalysts were prepared by impregnation using the TiZrO₄ solid solution obtained by co-precipitation as support. Among them， 0.5%Co/TiZrO₄ and 1%Co/TiZrO₄ showed low activity but considerable C₂H₄ selectivity （>90%） and carbon balance （≈100%）； 3%Co/TiZrO₄ appeared excellent C₂H₆ and CO₂ conversion during the whole process and obtained about 25% C₂H₄ yield at 650 ℃ and WHSV of 9000 mL?g^-1?h^-1. However， 5%Co/TiZrO₄ and 7.5%Co/TiZrO₄ exhibited a significant decrease in ethylene selectivity and severe coke deposition when the reaction temperature was higher than 600 ℃. SEM， XRD， Raman， UV-vis， XPS， H₂-TPR and in-situ Raman characterizations indicate that Co²⁺-TiZrO₄ possesses high C₂H₄ selectivity due to the strong metal-support interactions. Moderate amount of Co⁰ contributes to the activation of CO₂ and C₂H₆， while the aggregated bulk Co⁰ nanoparticles promote the dry-reforming reaction and coke deposition， resulting in catalyst deactivation.

Key words：CO₂ oxidative dehydrogenation of ethane ethylene Co-based catalysts metal-support interaction