Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO_(2)hydrogenation to methanol,Al_(2)O_(3),ZrO_(2)and CeO_(2)modified Cu-ZnO catalysts by the co-precipitation method were prep...Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO_(2)hydrogenation to methanol,Al_(2)O_(3),ZrO_(2)and CeO_(2)modified Cu-ZnO catalysts by the co-precipitation method were prepared,and the influence mechanism of additives on the structure-performance relationship of the catalysts was systematically explored.Through a variety of characterization methods such as XRD,N2 physical adsorption-desorption,TEM,H_(2)-TPR,CO_(2)-TPD and XPS,combined with catalytic performance evaluation experiments,the correlation between the microstructure of catalysts and the reaction performance of CO_(2)hydrogenation to methanol was analyzed in depth.The results show that metal additives significantly improve the performance of catalysts.After the introduction of additives,the specific surface area and pore volume of the catalysts increase,the grain size of Cu decreases,and its dispersion improves.The Ce-modified CZC catalyst exhibited the best performance,with the grain size of CuO as small as 11.41 nm,and the surface oxygen vacancy concentration(OⅡ/OⅠ=3.15)was significantly higher than that of other samples.The reaction performance test shows that under the conditions of 2.8 MPa,8000 h−1 and 280℃,the CO_(2)conversion of the CZC catalyst reached 18.83%,the methanol selectivity was 68.40%,and the methanol yield was 12.88%,all of which are superior to other catalysts.Its excellent performance can be attributed to the fact that CeO_(2)enhances the metal-support interaction,increases the surface basicity,promotes the adsorption and activation of CO_(2),and simultaneously inhibits the reverse water-gas shift side reaction.This study clarifies the structure-activity regulation mechanism of additive modification on Cu-ZnO catalysts,providing a theoretical basis and technical reference for the development of efficient catalysts for CO_(2)hydrogenation to methanol.展开更多
目的:通过对国际上太极拳相关研究进行文献计量、共现分析、共被引分析、聚类分析及可视化分析,探索太极拳近15年研究现状、热点及趋势,以期为未来研究提供一定指导。方法:以Web of Science中的Web of Science Core Collection数据库为...目的:通过对国际上太极拳相关研究进行文献计量、共现分析、共被引分析、聚类分析及可视化分析,探索太极拳近15年研究现状、热点及趋势,以期为未来研究提供一定指导。方法:以Web of Science中的Web of Science Core Collection数据库为文献来源,检索2004—2018年太极拳相关研究。运用CiteSpace软件以作者、国家和机构、关键词作为节点进行共现分析,并对关键词进行聚类分析、时间演化分析和Burst分析,选取被引文献作为节点进行共被引分析,绘制相应的可视化图谱并进行解读。结果:共检索到相关文献2242篇,近年来太极拳研究热度一直持续不减。研究者之间合作密切,贡献较为突出的研究者以Wayne PM为代表。国家及机构间也有密切的合作关系,其中,高产国家以美国、中国为代表,影响力较高的国家以加拿大为代表,研究机构多为大学。研究热点与前沿主要集中在对肌肉、骨骼等运动系统,对心、肺、血管等功能、对精神情志及本体感觉等的调控。预测太极拳研究领域近期将会出现更多的系统评价,同时太极拳对抑郁状态的影响、与瑜伽等运动方式的比较等相关研究近期将持续不断。结论:运用CiteSpace对Web of Science中太极拳近15年的研究进行了文献计量及可视化分析,相对直观地展现了太极拳近15年来的研究概况,初步地揭示了可合作的研究者及机构,对太极拳的研究热点、前沿及研究趋势形成了大致认识,为太极拳研究的选题、发展方向等提供了一定参考。展开更多
基金Supported by National Key R&D Program of China(2022YFA1503400)。
文摘Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO_(2)hydrogenation to methanol,Al_(2)O_(3),ZrO_(2)and CeO_(2)modified Cu-ZnO catalysts by the co-precipitation method were prepared,and the influence mechanism of additives on the structure-performance relationship of the catalysts was systematically explored.Through a variety of characterization methods such as XRD,N2 physical adsorption-desorption,TEM,H_(2)-TPR,CO_(2)-TPD and XPS,combined with catalytic performance evaluation experiments,the correlation between the microstructure of catalysts and the reaction performance of CO_(2)hydrogenation to methanol was analyzed in depth.The results show that metal additives significantly improve the performance of catalysts.After the introduction of additives,the specific surface area and pore volume of the catalysts increase,the grain size of Cu decreases,and its dispersion improves.The Ce-modified CZC catalyst exhibited the best performance,with the grain size of CuO as small as 11.41 nm,and the surface oxygen vacancy concentration(OⅡ/OⅠ=3.15)was significantly higher than that of other samples.The reaction performance test shows that under the conditions of 2.8 MPa,8000 h−1 and 280℃,the CO_(2)conversion of the CZC catalyst reached 18.83%,the methanol selectivity was 68.40%,and the methanol yield was 12.88%,all of which are superior to other catalysts.Its excellent performance can be attributed to the fact that CeO_(2)enhances the metal-support interaction,increases the surface basicity,promotes the adsorption and activation of CO_(2),and simultaneously inhibits the reverse water-gas shift side reaction.This study clarifies the structure-activity regulation mechanism of additive modification on Cu-ZnO catalysts,providing a theoretical basis and technical reference for the development of efficient catalysts for CO_(2)hydrogenation to methanol.
文摘目的:通过对国际上太极拳相关研究进行文献计量、共现分析、共被引分析、聚类分析及可视化分析,探索太极拳近15年研究现状、热点及趋势,以期为未来研究提供一定指导。方法:以Web of Science中的Web of Science Core Collection数据库为文献来源,检索2004—2018年太极拳相关研究。运用CiteSpace软件以作者、国家和机构、关键词作为节点进行共现分析,并对关键词进行聚类分析、时间演化分析和Burst分析,选取被引文献作为节点进行共被引分析,绘制相应的可视化图谱并进行解读。结果:共检索到相关文献2242篇,近年来太极拳研究热度一直持续不减。研究者之间合作密切,贡献较为突出的研究者以Wayne PM为代表。国家及机构间也有密切的合作关系,其中,高产国家以美国、中国为代表,影响力较高的国家以加拿大为代表,研究机构多为大学。研究热点与前沿主要集中在对肌肉、骨骼等运动系统,对心、肺、血管等功能、对精神情志及本体感觉等的调控。预测太极拳研究领域近期将会出现更多的系统评价,同时太极拳对抑郁状态的影响、与瑜伽等运动方式的比较等相关研究近期将持续不断。结论:运用CiteSpace对Web of Science中太极拳近15年的研究进行了文献计量及可视化分析,相对直观地展现了太极拳近15年来的研究概况,初步地揭示了可合作的研究者及机构,对太极拳的研究热点、前沿及研究趋势形成了大致认识,为太极拳研究的选题、发展方向等提供了一定参考。
