najoNanosystems: Physics, Chemistry, MathematicsНаносистемы: физика, химия, математика2220-80542305-7971Университет ИТМО10.17586/2220-8054-2020-11-2-246-251najo-451Research ArticleCHEMISTRY AND MATERIALS SCIENCEХИМИЯ И НАУКА О МАТЕРИАЛАХInfluence of hydrothermal synthesis conditions on the composition of the pyrochlore phase in the Bi2O3–Fe2O3–WO3 systemLomakinM. S.

26, Politekhnicheskaya St., 194021, St. Petersburg

26, Moskovsky pr, 190013, St. Petersburg

lomakinmakariy@gmail.comProskurinaO. V.

26, Politekhnicheskaya St., 194021, St. Petersburg

26, Moskovsky pr, 190013, St. Petersburg

GusarovV. V.

26, Politekhnicheskaya St., 194021, St. Petersburg

Ioffe Institute; St. Petersburg State Institute of TechnologyRussian FederationIoffe InstituteRussian Federation202030072025112246–251Copyright © Lomakin M.S., Proskurina O.V., Gusarov V.V., 20252025Lomakin M.S., Proskurina O.V., Gusarov V.V.Lomakin M.S., Proskurina O.V., Gusarov V.V.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://nanojournal.ifmo.ru/jour/article/view/451

The paper deals with a study of the effect which the hydrothermal fluid pH has on the formation of a pyrochlore-structured phase in the Bi2O3– Fe2O3–WO3 system. It was shown that at pH of 1 and 8, the formation of pyrochlore-structured phase particles with crystallite sizes of 38 and 118 nm, respectively, is accompanied by the formation of the Bi2WO6 compound with the Aurivillius phase structure. At pH values from 2 to 7, only pyrochlore-structured nanocrystalline particles with a variable composition are formed. Under these conditions, the dependence of the average size of crystallites of the pyrochlore-structured phase particles on pH is extreme, as the size increases from ∼ 67 nm at pH 2 up to ∼ 126 nm at pH 5 and then decreases to ∼ 102 nm at pH 7. The samples obtained at pH 3–4 have a composition that is the closest to that specified for the synthesis.

When pH increases up to 10, there forms a non-single-phase product that contains the Bi2WO6 phase and δ-Bi2O3-based phase.

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The authors declare that there are no conflicts of interest present.