Magnetic, oxidation and reduction behavior of spinel Ni–Cu manganite NixCu1-xMn2O4 powders

Graphical abstract: Conversion, % as a function of catalyst composition at room temperature and 200 °C for the system NixCu1-xMn2O4 (X = 0, 0.3, 0.5, 0.7, and 1.0, respectively). -- Highlights: • Catalytic oxidation of NixCu1-xMn2O4 was studied. • Forty percentage of CO was converted into CO2 at 200 °C. • Ni/MnO and Cu/MnO composites were developed by H2 gas reduction. • Monodisperesed particles were formed. • Ms of NiMn2O4 was duplicated 15 times as the results of reduction. -- Abstract: Nickel copper manganites, NixCu1-xMn2O4 (where 0 ≤ X ≤ 1), powders have been synthesized via co-precipitation method. The formed particles were obtained from the precipitate precursors annealed at 800 °C for 2 h. The prepared powders were tested for the catalytic oxidation of carbon monoxide (CO) into carbon dioxide (CO2). The results indicated that the intermediate compositions displayed better catalytic activity than the end compositions for CO oxidation due to the phenomena of synergism. The composition of x = 0.3 and 0.5 showed rapid rise in CO conversion with temperature; about 40% conversion was achieved at 200 °C for the produced manganite sample of chemical composition Cu0.7Ni0.3Mn2O4. A correlation between magnetic properties and hydrogen reduction of manganites was demonstrated. Magnetic properties of reduced manganite were found to be duplicated. The saturation magnetization of reduced NiMn2O4 into Ni/MnO was duplicated of order 15 times from initial value