Solid-State Transformations in Inner Coordination Sphere of [Co(NH₃)₆][Fe(C₂O₄)₃]∙3H₂O as a Route to Access Catalytically Active Co-Fe Materials

Denis P Domonov; Sophia I Pechenyuk; Yulia P Semushina; Kirill V Yusenko

doi:10.3390/ma12020221

Solid-State Transformations in Inner Coordination Sphere of [Co(NH₃)₆][Fe(C₂O₄)₃]∙3H₂O as a Route to Access Catalytically Active Co-Fe Materials

Materials (Basel). 2019 Jan 10;12(2):221. doi: 10.3390/ma12020221.

Authors

Denis P Domonov¹, Sophia I Pechenyuk², Yulia P Semushina³, Kirill V Yusenko⁴

Affiliations

¹ I.V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials of RAS KSC (ICTREMR), Akademgorodok, 26a, Apatity, Murmansk region 184209, Russia. domonov@chemy.kolasc.net.ru.
² I.V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials of RAS KSC (ICTREMR), Akademgorodok, 26a, Apatity, Murmansk region 184209, Russia. pechenyuk@chemy.kolasc.net.ru.
³ I.V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials of RAS KSC (ICTREMR), Akademgorodok, 26a, Apatity, Murmansk region 184209, Russia. semushina@chemy.kolasc.net.ru.
⁴ BAM Federal Institute of Materials Research and Testing, Richard-Willstätter Str. 11, D-12489 Berlin, Germany. kirill.yusenko@bam.de.

Abstract

Thermal decomposition of [Co(NH₃)₆][Fe(C₂O₄)₃]∙3H₂O in argon atmosphere, at a low heating rate (3°/min), and in large amounts of the initial complex (~0.1 mole), has been studied. It was possible to distinguish four decomposition steps upon heating: In the temperature range of 50⁻100 °C-the loss of crystal water; 100⁻190 °C-stability region of dehydrated complex; 230⁻270 °C-the range of stability of intermediate phase with the formula CoFe(NH₃)₂(C₂O₄)₂; 270⁻350 °C-thermal decomposition of the intermediate with the formation of metallic products and further air oxidation with the formation of Co_1.5Fe_1.5O₄. Catalytic properties of thermolysis products were tested in the decomposition reaction of H₂O₂ (inactive), oxidation of acetone (average activity), and decomposition of ammonium perchlorate (highly active).

Keywords: catalyst; coordination sphere; double complex salts; single-source precursor; thermal decomposition.