等离子体在绿色制备催化剂方面的应用:现状及展望（英文）
发布时间：2018-11-08 13:13
【摘要】：催化在现代化工生产中正发挥非常重要的作用.在未来催化甚至会扮演更重要的角色.然而,现有的催化剂制备方法会对空气、水和土地造成污染.这些污染主要来源于催化剂制备过程中会用到的各种有害化学品.而且,现有催化剂制备过程耗时长、耗能高、用水量大.这些都不符合绿色化学原则.因此,开展催化剂绿色制备研究十分必要.这一研究的长远目标是避免或者消除催化剂制备过程每一环节产生的污染,降低每一环节的能耗和物耗,缩短制备时间,减少劳动强度.显然,这并不是一个容易达成的目标.因此,朝着上述长远目标的任何进展,无论是小进展还是大进展,都将有助于最终实现催化剂的绿色制备.我们总结了气体放电冷等离子体在催化剂绿色制备方面的最新进展,特别强调了非氢冷等离子体在催化剂制备中的应用.冷等离子体是一种能在室温附近操作的非平衡等离子体,是对气体施加一定电压(数百至上万伏特;具体电压值取决于气体压力)形成的.冷等离子体制备方法可以在少用或者不用有害化学品的基础上,有效减小催化剂粒径、增加催化剂分散度、提高催化剂和载体的相互作用等.这些改进同时能进一步提高催化剂的活性和稳定性.相对于常规热化学制备催化剂,冷等离子体制备的显著区别在于:冷等离子体在室温或者略高于室温条件下操作,可以有效避免热化学方法存在的缺点.冷等离子体方法利用其富含的高能物质(如电子)快速促进催化剂前驱体分解,从而实现催化剂快速成核.由于低温操作,其晶体生长速度受到限制,催化剂分散性得以提高.研究表明,以非氢等离子体作为电子源的室温电子还原能够有效还原贵金属离子.这个过程中既不需要有害化学还原剂也不需要氢还原.这为以热敏材料和化学不稳定物质作为基底的负载型催化剂制备创造了条件.这些热敏材料包括金属有机骨架材料(MOF)、共价有机骨架材料(COF)、高比表面积的碳、多肽、DNA和蛋白质等等.这个室温电子还原还被用于制备能在水面或其它溶液表面上漂浮的催化剂,对发展新型催化剂有很大帮助.此外,使用冷等离子体还可以进行低温模板脱除,以避免高温分解可能出现的烧结问题,在保证催化剂高比表面积的同时获得只有在高温分解才能得到的结构特征.研究表明,可以使用冷等离子体诱发微燃烧以除去炭模板,可以有效减少炭模板法制备氧化物结构材料所需要的化学品.冷等离子体方法在催化剂制备中的应用刚刚开始,尚有大量研究还有待于开展(如多金属氧化物制备等),存在大量研发机会.可以预期,冷等离子体在催化剂绿色制备与应用中将发挥更重要的作用.
[Abstract]:Catalysis is playing a very important role in modern chemical production. Catalysis will play an even more important role in the future. However, existing methods of preparing catalysts can pollute air, water and land. These pollution mainly come from various harmful chemicals used in the preparation of catalysts. Moreover, the existing catalyst preparation process takes a long time, high energy consumption and high water consumption. None of this is in line with green chemistry principles. Therefore, it is necessary to study the green preparation of catalysts. The long-term goal of this study is to avoid or eliminate the pollution in every link of catalyst preparation, to reduce energy consumption and material consumption, to shorten preparation time and to reduce labor intensity. Clearly, this is not an easy goal to achieve. Therefore, any progress towards these long-term goals, whether small or significant, will contribute to the eventual green preparation of catalysts. The recent progress in the green preparation of catalysts by gas discharge cold plasma is summarized, especially the application of non-hydrogen cold plasma in the preparation of catalysts is emphasized. Cold plasma is a kind of non-equilibrium plasma which can operate near room temperature. It is formed by applying a certain voltage (hundreds to tens of thousands volts; the specific voltage depends on the pressure of the gas). The cold plasma preparation method can effectively reduce the particle size of the catalyst, increase the dispersion of the catalyst and improve the interaction between the catalyst and the support on the basis of less or no harmful chemicals. These improvements can further improve the activity and stability of the catalyst. Compared with conventional thermochemical preparation catalysts, the difference of cold plasma preparation is that cold plasma operating at room temperature or slightly higher than room temperature can effectively avoid the disadvantages of thermochemical method. The cold plasma method can rapidly promote the decomposition of catalyst precursors by using its rich high energy materials (such as electrons) so as to realize the rapid nucleation of catalysts. Due to the low temperature operation, the crystal growth rate is limited and the dispersion of the catalyst is improved. The results show that the room temperature electron reduction with non-hydrogen plasma as the electron source can effectively reduce noble metal ions. This process requires neither harmful chemical reductants nor hydrogen reduction. This creates conditions for the preparation of supported catalysts based on thermosensitive materials and chemical unstable substances. These thermosensitive materials include metal-organic skeleton material (MOF), covalent organic skeleton material (COF), with high specific surface area carbon polypeptide DNA and protein. This room temperature electron reduction is also used to prepare catalysts that can float on the surface of water or other solutions, which is of great help to the development of new catalysts. In addition, the cold plasma can be used to remove the template at low temperature to avoid the possible sintering problem of the decomposition at high temperature, and to obtain the structural characteristics which can only be obtained by decomposition at high temperature while ensuring the high specific surface area of the catalyst. The results show that the cold plasma-induced micro-combustion can be used to remove the carbon template, and the chemicals needed for the preparation of oxide structure materials can be effectively reduced by the carbon template method. The application of the cold plasma method in the preparation of catalysts is just beginning, there are still a lot of research needs to be carried out (such as the preparation of polymetallic oxides), there are a lot of research and development opportunities. It is expected that cold plasma will play a more important role in the green preparation and application of catalysts.
【作者单位】： 天津大学化工学院天津化学化工协同创新中心;
【基金】：supported by the National Natural Science Foundation of China(20990223 and 21476157)~~
【分类号】：O643.36
，
本文编号：2318602
[Abstract]:Catalysis is playing a very important role in modern chemical production. Catalysis will play an even more important role in the future. However, existing methods of preparing catalysts can pollute air, water and land. These pollution mainly come from various harmful chemicals used in the preparation of catalysts. Moreover, the existing catalyst preparation process takes a long time, high energy consumption and high water consumption. None of this is in line with green chemistry principles. Therefore, it is necessary to study the green preparation of catalysts. The long-term goal of this study is to avoid or eliminate the pollution in every link of catalyst preparation, to reduce energy consumption and material consumption, to shorten preparation time and to reduce labor intensity. Clearly, this is not an easy goal to achieve. Therefore, any progress towards these long-term goals, whether small or significant, will contribute to the eventual green preparation of catalysts. The recent progress in the green preparation of catalysts by gas discharge cold plasma is summarized, especially the application of non-hydrogen cold plasma in the preparation of catalysts is emphasized. Cold plasma is a kind of non-equilibrium plasma which can operate near room temperature. It is formed by applying a certain voltage (hundreds to tens of thousands volts; the specific voltage depends on the pressure of the gas). The cold plasma preparation method can effectively reduce the particle size of the catalyst, increase the dispersion of the catalyst and improve the interaction between the catalyst and the support on the basis of less or no harmful chemicals. These improvements can further improve the activity and stability of the catalyst. Compared with conventional thermochemical preparation catalysts, the difference of cold plasma preparation is that cold plasma operating at room temperature or slightly higher than room temperature can effectively avoid the disadvantages of thermochemical method. The cold plasma method can rapidly promote the decomposition of catalyst precursors by using its rich high energy materials (such as electrons) so as to realize the rapid nucleation of catalysts. Due to the low temperature operation, the crystal growth rate is limited and the dispersion of the catalyst is improved. The results show that the room temperature electron reduction with non-hydrogen plasma as the electron source can effectively reduce noble metal ions. This process requires neither harmful chemical reductants nor hydrogen reduction. This creates conditions for the preparation of supported catalysts based on thermosensitive materials and chemical unstable substances. These thermosensitive materials include metal-organic skeleton material (MOF), covalent organic skeleton material (COF), with high specific surface area carbon polypeptide DNA and protein. This room temperature electron reduction is also used to prepare catalysts that can float on the surface of water or other solutions, which is of great help to the development of new catalysts. In addition, the cold plasma can be used to remove the template at low temperature to avoid the possible sintering problem of the decomposition at high temperature, and to obtain the structural characteristics which can only be obtained by decomposition at high temperature while ensuring the high specific surface area of the catalyst. The results show that the cold plasma-induced micro-combustion can be used to remove the carbon template, and the chemicals needed for the preparation of oxide structure materials can be effectively reduced by the carbon template method. The application of the cold plasma method in the preparation of catalysts is just beginning, there are still a lot of research needs to be carried out (such as the preparation of polymetallic oxides), there are a lot of research and development opportunities. It is expected that cold plasma will play a more important role in the green preparation and application of catalysts.
【作者单位】： 天津大学化工学院天津化学化工协同创新中心;
【基金】：supported by the National Natural Science Foundation of China(20990223 and 21476157)~~
【分类号】：O643.36
，
本文编号：2318602
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