METHOD OF PRODUCING PHOTO CATALYST BASED ON ALKALINE EARTH METAL BISMUTATES Russian patent published in 2017 - IPC B01J37/08 B01J23/843 C01G29/00 

FIELD: chemistry.

SUBSTANCE: method of producing a photocatalyst based on alkaline earth metal bismuthate is to dissolve a mixture of bismuth nitrate Bi(NO₃)₃ and inorganic salt of alkaline earth metal Me, followed by standing of the products of their hydrolysis to form particles with bismuth ions evenly distributed by their volume and unevenly distributed alkaline earth ions and removal of excess moisture from the hydrolysis products, heating the produced particles to form particles as a heterostructure from amorphous by structure and stoichiometric by composition alkaline earth metal bismuthate and amorphous by structure and stoichiometric by composition bismuth oxide Bi₂O₃ followed by their crystallization. Herewith as inorganic salt of alkaline earth metal Me, alkaline earth metal oxalate MeC₂O₄ is taken, before dissolving alkaline earth metal oxalate MeC₂O₄ is purified from the adsorbed compounds and mixed with bismuth nitrate Bi(NO₃)₃, maturation of the products of their hydrolysis leads to the formation of particles of alkaline earth metal oxalate MeC₂O₄ impregnated with ions Bi(OH)²⁺, with evenly distributed bismuth ions and unevenly distributed alkaline earth metal ions, removal of excess moisture from the products of hydrolysis leads to the formation of precursor-particles in the form of heterostructures with the central part of alkaline earth metal oxalate MeC₂O₄impregnated with ions Bi(OH)²⁺ and the outer shell of bismuth hydroxonitrate Bi(OH)(NO₃)₂, heating the precursor-particles is carried out at two stages to form alkaline earth metal carbonate MeCO₃impregnated with ions Bi(OH)²⁺, in the central part of each particle in the first stage and up to the formation of amorphous particles in the form of heterostructures with a central area of amorphous by structure and stechiometric by composition alkaline earth metal bismutite and the surface layer of the amorphous by structure and stechiometric by composition bismuth oxide Bi₂O₃ at the second stage, crystallization leads to the formation of particles of the photocatalyst in the form of heterostructures with the central area of crystalline by structure and stechiometric by composition alkaline earth metal bismutite and the surface layer of crystalline by structure and stechiometric by composition bismuth oxide Bi₂O₃. For mixing, the components are taken in the following ratio, wt %: alkaline earth metal oxalate MeC₂O₄ 4.49-3.63, bismuth nitrate Bi(NO₃)₃ 95.51-96.37, dissolution is carried out in distilled water with the following ratio of components, wt %: mixture of alkaline earth metal oxalate powders MeC₂O₄ and bismuth nitrate Bi(NO₃)₃ 5.00-15.00, distilled water 95.00-85.00, heating of precursor-particles at the first stage is carried out up to 520°C with a heating rate of 0.5-1.0°C/min, at the second stage - up to 810°C with a heating rate of 1.0-2.0°C/min, the crystallization is carried out at a temperature of 750-825°C.

EFFECT: increasing the lifetime of the catalytic properties of the photocatalyst.

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