В настоящей работе мы провели синтез палладий-висмутовых катализаторов, нанесенных на оксид алюминия, и исследовали процессы, протекающие при взаимодействии предшественников иPd(acac)2 и Bi(ac)3 с оксидом алюминия

Sandu, Mariya Petrovna

Zuza, Daniil A.

English

Tomsk State University Repository

МИНИСТЕРСТВО НАУКИ И ВЫСШЕГО ОБРАЗОВАНИЯ РОССИЙСКОЙ ФЕДЕРАЦИИПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУКТом 2. ХимияСборник научных трудовXIX Международной конференции студентов, аспирантови молодых ученых26-29 апреля 2022 г.PROSPECTS OF FUNDAMENTAL SCIENCES DEVELOPMENTVolume 2. ChemistryAbstractsXIX International Conference of students, graduate studentsand young scientistsApril 26-29, 2022томскийПОЛИТЕХНИЧЕСКИЙУНИВЕРСИТЕТТомскил государственный университетсистем уиравленин и радиоэлектроникиТомск 2022XIX МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ, АСПИРАНТОВ И МОЛОДЫХ УЧЕНЫХ«ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК» 197УДК 544.14REGULARITIES OF THE FORMATION OF Pd-Bi NANOPARTICLES OBTAINED BY SUPPORT OFORGANOMETALLIC PRECURSORS ON Al2O3M.P. Sandu1, D.A. Zuza2 Scientific Supervisor: Prof., Dr. I.A. Kurzina 1 Tomsk State University, Russia, Tomsk, Lenin str., 36, 634050 2 Institute of High Current Electronics SB RAS, Tomsk, Akademichesky Ave., 2/3, 634055E-mail: mpsandu94@,gmail.comЗАКОНОМЕРНОСТИ ФОРМИРОВАНИЯ Pd-Bi НАНОЧАСТИЦ, ПОЛУЧЕННЫХ НАНЕСЕНИЕМ МЕТАЛЛООРГАНИЧЕСКИХ ПРЕДШЕСТВЕННИКОВ НА Al2O3М.П. Санду1, Д.А. Зуза2Научный руководитель: профессор, д.ф-м.н. И.А. Курзина 1 Национальный исследовательский Томский государственный университет,Россия, г. Томск, пр. Ленина, 30, 634050 2 Институт сильноточной электроники СО РАН Россия, г. Томск, пр-кт Академический, 2/3, 634055 E-mail: mpsandu94@,gmail.comАннотация. В настоящей работе мы провели синтез палладий-висмутовых катализаторов, нанесенных на оксид алюминия, и исследовали процессы, протекающие при взаимодействии предшественников Pd(acac)2 и Bi(ac)s с оксидом алюминия.Introduction. Supported palladium-bismuth catalysts have found wide application in various reactions involving hydrogen transfer, such as the production of polyhydroxycarboxylic acids [1], hydrogen [2], and the hydrodechlorination of dangerous chlorine-containing compounds [3]. Palladium has a high ability to adsorb hydrogen, and bismuth has a promoting effect preventing the oxidation of palladium active sites. The main preparation method of palladium-bismuth catalysts is the using of chloride-containing precursors that block active centers by strong binding to the palladium surface. This work is devoted to the investigation of the formation processes of palladium-bismuth nanoparticles supported on alumina from a non-aqueous solution of Pd(acac)2 and Bi(ac)s precursors.Research methods. The Pd-Bi/Al2Os catalyst with an atomic ratio Pd:Bi = 2:1 was obtained by co­impregnation of Pd(acac)2 and Bi(ac)s precursors from an acetic acid solution. Next, the excess solvent was removed in a rotary evaporator. The catalyst was subjected to a three-step heat treatment in argon, oxygen and hydrogen atmospheres. Monometallic Pd/Al2Os and Bi/Al2Os samples were prepared in the same method as reference samples. Next, the catalyst surface was studied by X-ray fluorescence spectroscopy, transmission electron microscopy, thermally programmed reduction, and X-ray photoelectron spectroscopy. The specific surface area and porosity of the catalyst were determined by the BET and BJH methods, respectively.Results. Characteristics of the catalyst are presented in Table 1.Россия, Томск, 26-29 апреля 2022 г. Том 2. Химия198 XIX МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ, АСПИРАНТОВ И МОЛОДЫХ УЧЕНЫХ«ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК»Table 1Characteristics o f Pd-Bi/Al^Os catalystContent of metals Sbet, m2/g Vpore, cm3/g Dpore, nmPd -  1.8 wt%, Bi -  1.8 wt% 239 0.32 3.70The TEM image allows us to conclude that the particles are spherical or close to this shape (Figure 1 a). The average particle size (Figure 1b) is ~7 nm, but large particles (up to 40 nm) make a small contribution.'^ Г Ы  Гс1'Fig. 1. TEM image (a), particle size distribution histogram (b), TPR pattern o f Pd-Bi/Al2 OsPeaks of the reduction of the preoxidized states of Pd and Bi were found for monometallic samples of Pd/Al2O3 and Bi/Al2O3 in the TPR patterns. The peak of hydrogen absorption by PdO corresponds to 40 °C. The negative peak at 97 °C refers to the desorption of p-PdH formed during the hydrogen absorption. The reduction of Bi2O3 in Bi/Al2O3 sample begins at 380°C, and the bulk reduction occurs at ~500°C. In the TPR patterns of the bimetallic Pd-Bi/Al2O3 sample. However, there is no Bi reduction peak, and the Pd reduction peak has a low intensity and is shifted to 53 °С. The reason for this behavior of the Pd-Bi/Al2O3 sample is the formation of a mixed PdxBiy phase at the stage of catalyst preparation.We have given a thorough consideration to the state of the levels of palladium Pd 3d, Bi 4f, Al 2p, and C 1s for palladium-bismuth catalysts by XPS after the final stage of sample reduction in a hydrogen atmosphere.. The XPS patterns of the surface of the PdBi/Al2O3 catalyst are shown in Figs. 2 and 3. The Pd0, Pd(n)ads, Bi0, and Bi(III) states were found in the Pd 3d and Bi 4f line patterns (Figs. 2 a, b). The presence of oxidized forms is associated with the fixation of metal particles through the oxygen-containing groups of the Al2O3 support.Fig. 2. XPS patterns o f the Pd 3d (a) and Bi 4 f levels on the PdBi/Al2Qs catalyst surfaceWe have found the presence of a metallic bond of aluminum Al-Al and aluminum with oxygen Al-O, Al-C, oxycarbide state of aluminum Al-O-C, the presence of hydrocarbon (C-H) and carbonyl (C=O) groups,Россия, Томск, 26-29 апреля 2022 г. Том 2. ХимияXIX МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ, АСПИРАНТОВ И МОЛОДЫХ УЧЕНЫХ«ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК» 199as well as a polymorphic modification of carbon (graphite) in the spectra of Al 2p, C 1s (Fig. 3 a, b). The presence of Al-O-C and Al-C bonds is a consequence of the fact that alumina forms surface compounds of acetylacetone with aluminum of the composition [Al(acac)x]s(x-3)+ at the stage of interaction with precursor solutions. The surface acetylacetonate decomposes to form an acetate complex with aluminum [Al(Oac)2]+s upon thermolysis in an argon atmosphere, which subsequently dissociates to form alumina. However, the presence of Al-O-C and Al-C states in the XPS spectra after all thermal treatments indicates that the decomposition of the [Al(acac)x]s(x-3)+ surface complex was incomplete, and the catalyst support is present: aluminum oxide [Al-O]s and aluminum acetate complex [Al(Oac)2]+s strongly bonded to the surface. The presence of such surface form can contribute to the additional fixation of metal nanoparticles on the support through acetate or acetylacetonate functional groups.290 288 286 284 282Fig. 3. XPS patterns of the Al 2p (a) and C 1s levels on the PdBi/Al2 Os catalyst surface Conclusion. The bimetallic catalyst Pd-Bi/Al2O3 was obtained by diffusion co-impregnation from acetic acid solution of Pd(acac)2 and Bi(ac)3 precursors. We have establish the presence of the surface compound [Al(Oac)2]+s which can stabilize Pd and Bi particles on the support surface through the oxygen-containing groups of Al2O3.This research was financially supported by the Ministry of Science and Higher Education (Grant no. 0721-2020-0037).REFERENCESSandu M. et al. In^uence of the Pd: Bi ratio on Pd-Bi/Al2O3 catalysts: structure, surface and activity in glucose oxidation // Physical Chemistry Chemical Physics. -  2021. -  V. 23, № 27. -P. 14889-14897.Qin, X. et al. Mechanistic analysis-guided Pd-based catalysts for efficient hydrogen production from formic acid dehydrogenation // ACS Catalysis. -  2020. -  V. 10, № 6. -  P. 3921-3932.Ohnishi, R., Suzuki, I., Ichikawa, M. Bi-Pd Catalyst for Selective Hydrodechlorination of 1,1,2- Trichlorotri^uoroethane to Tri^uoroethene, a Key Intermediate to 1,1,1,2-Tetra^uoroethane as a CFC Replacement for Refrigeration. // Chem. Lett. -  1991. -  V. 20, № 5. -  P. 841-844.Россия, Томск, 26-29 апреля 2022 г. Том 2. Химия

Закономерности формирования Pd-Bi наночастиц, полученных нанесением металлоорганических предшественников на Al2O3

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Закономерности формирования Pd-Bi наночастиц, полученных нанесением металлоорганических предшественников на Al2O3

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