Role of Preparation Conditions in Defining the Final Characteristics of Pt/Sibunit Catalysts Доклады на конференциях
Язык | Английский | ||||
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Тип доклада | Стендовый | ||||
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28th International Scientific Conference for Undergraduate and Graduate Students and Young Scientists "Lomonosov" 12-23 апр. 2021 , Москва |
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Реферат:
Heterogeneous catalysts based on active component Pt and carbon support Sibunit are of pivotal importance due to the high catalytic activity of platinum in various reactions [1] and Sibunit with high mechanical crushing, good abrasion strength, and a high surface area [2]. It has been found out in numerous investigations that phase compositions, particle size, and the nature of support are decisive factors for the activity and selectivity of supported catalysts [1]. These influential parameters strongly rely on the conditions of the preparation of catalysts. Therefore, an intensive approach to investigate the influence of preparations conditions on the final characteristics of Pt/Sibunit support catalysts was demanding to provide a systematic solution for the targeted applications of catalysts.
This work was aimed to define the role of preparation conditions on the formation of active component particles of Pt over Sibunit support. In order to achieve this goal, multiple sets of catalysts were synthesized by changing the preparation conditions such as pretreatment of Sibunit, platinum precursor solution composition [1], and reductants. Samples were analyzed by XPS (X-ray photoelectron spectroscopy), TEM (transmission electron microscopy), and BET adsorption method at each stage of preparation.
The comparison of original and pretreated Sibunit with 70% concentrated HNO3 at room temperature was made based on the BET adsorption study that showed a significant increase in surface area and volume of pores due to etching of the surface of Sibunit. Moreover, XPS indicated the appearance of -NO2 groups and the increase of the amount of oxygen functional groups after pretreatment of Sibunit. These additional functional groups are responsible for the surface modification and act as adsorption sites. Then Pt (IV) nitrate solution and same solution modified with TMA (tetramethylammonium hydroxide) deposited separately on original and pretreated Sibunit by wet impregnation method [1] were studied with XPS. According to XPS data, depth of Pt reduction just after precursor deposition was high in the case of using TMA modified Pt precursor solution and HNO3 pre-treated Sibunit due to strong interaction between active component and support. It can be expected that the difference in ‘active component – support’ interaction defined at the preparation stage is critically important for the catalytic behavior and system stability under reaction conditions [1]. NaBH4 and H2 were used as reductants and all the reduced catalysts were analyzed both by XPS and TEM. It showed wide particle size distribution due to agglomeration and migration of particles in case of H2 and uniform and narrow particle size distribution with a mean size of 2.1 nm (original) and 2.5 nm (Sibunit pretreated with HNO3) when NaBH4 is used with TMA modified precursor.
The XPS, TEM, and BET studies of Pt/Sibunit catalysts at each varied preparation condition provide a solution to control the final characteristics such as chemical states and particle size distribution of the final catalysts.
This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for Boreskov Institute of Catalysis (project AAAA-A21-121011390011-4).
Библиографическая ссылка:
Shahzad A.
Role of Preparation Conditions in Defining the Final Characteristics of Pt/Sibunit Catalysts
28th International Scientific Conference for Undergraduate and Graduate Students and Young Scientists "Lomonosov" 12-23 Apr 2021
Role of Preparation Conditions in Defining the Final Characteristics of Pt/Sibunit Catalysts
28th International Scientific Conference for Undergraduate and Graduate Students and Young Scientists "Lomonosov" 12-23 Apr 2021