Thermal decomposition of d-metal nitrates supported on alumina

Abstract

The thermal decomposition of cobalt, nickel, manganese, zinc, and copper nitrates supported on nanometric alumina was investigated and compared with decomposition of corresponding bulk nitrates. TG, DTA, and MS measurements in air were performed. The supported nitrates decompose in lower temperatures than the bulk ones and their decomposition proceeds in fewer stages which are better separated. Synthesized materials and bulk nitrates before degradation of nitrates groups undergo dehydration. For decomposition of manganese and copper nitrates, the last step of water vapour releasing is combined with degradation of nitrate groups thus formation of anhydrous metal nitrate during decomposition is not achievable. Thermal decomposition of bulk nitrates leads to oxides-Co 3 O 4 , NiO, MnO 2 , ZnO, and CuO-respectively, as the solid residue. The nickel, zinc, copper, and manganese nitrates while supported on alumina decompose to corresponding oxides (NiO, ZnO, CuO, MnO 2 ) as well. For decomposition of cobalt nitrate while supported on Al 2 O 3 as the solid residue CoAl 2 O 4 were identified. The correlation between dehydration and degradation of nitrates groups temperatures for bulk and supported nitrates was analysed in terms of atomic properties of d-metals.

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

“…The main decomposition product of cobalt nitrate (as well as that of nickel, iron nitrates) is NO 2 with N 2 O and nitric oxide, NO, being the other products [31,[39][40][41][42]. Here we are not concerned with the detail of the catalyst precursor decomposition but to reveal the effect of coated silica on decomposition.…”

Formation of three-dimensional arrays of magnetic clusters NiO, Co3O4, and NiCo2O4 by the matrix method

“…With a further increase in the temperature, the nitrates undergo decomposition. The products of their thermal degradation at temperatures of 250-300°C are the oxide compounds NiO and Co 3 O 4 [14]. It can be seen from Table 1 that the molar volume of the material in the pores after the decomposition decreases by a factor of approximately 10-15.…”

“…The Ni(NO 3 ) 2 · 6H 2 O and Co(NO 3 ) 2 · 6H 2 O melts wetting the SiO 2 surface (the melting temperatures of both compounds are equal to 56°C) completely fill the pores of the opal under the action of capillary forces. Then, during the gradual heating, the multistage dehydration of the crystal hydrates occurs with intermediate stages of the formation of solid basic nitrates, which results in the formation of anhydrous nitrates Ni(NO 3 ) 2 and Co(NO 3 ) 2 at a temperature of 200°C [14]. With a further increase in the temperature, the nitrates undergo decomposition.…”

Design of high‐performance flexible symmetric supercapacitors energized by redox‐mediated hydrogels including metal‐doped acidic polyelectrolyte

“…The first weight change occurred between 175°C and 211°C, resulting in 5% to 15% weight loss, which could be described by inter‐chain condensation of acidic units. The next domain starts above 258°C, resulting in the further condensation of acidic units as well as removal of nitrates . Further degradation of the PVPA/NiX‐based redox‐mediated electrolytes was observed above 430°C.…”

“…The next domain starts above 258 C, resulting in the further condensation of acidic units as well as removal of nitrates. 34 Further degradation of the PVPA/NiX-based redox-mediated electrolytes was observed above 430 C.…”