Cobalt-iron oxides made by CVD for low temperature catalytic application

Abstract

Thin films of cobalt‐iron oxides (CoFe2O4) with spinel‐type structure were prepared by pulsed‐spray evaporation chemical vapor deposition (PSE‐CVD) using Fe(acac)3 and Co(acac)3 as precursors. The optimal depositions of CVD‐type growth have been established and such growth can be achieved at 400 °C. The obtained films have been systematically characterized in terms of structure (XRD and Raman), surface, and bulk composition (XPS and EDS) as well as morphology (SEM). CoFe2O4 has been successfully tested as an active catalyst toward total oxidation of CO, C3H6, dimethyl ether (DME), and n‐C4H8. The results indicate that both the lattice and adsorbed oxygen presented at the surface of the catalyst play determinant roles in the catalytic oxidation process.

CVD‐Made Spinels: Synthesis, Characterization and Applications for Clean Energy

“…The oxidation of C 3 H 6 and n-C 4 H 8 on CoFe 2 O 4 starts at temperatures lower than that of DME and the trend for the rate of oxidation is C 3 H 6 ≈ n-C 4 H 8 > DME [26]. In the presence of CoFe 2 O 4 nanoparticles, the oxidation becomes detectable at around 250°C for C 3 H 6 and n-C 4 H 8 and 285°C for DME and the T 90 is 334, 371 and 470°C for C 3 H 6 , n-C 4 H 8 and DME, respectively.…”

“…In order to further improve the catalytic performance of TMOs, some combinations of oxides have been formulated and the obtained binary or mixed TMOs have exhibited better activities than the single or mixed components or even comparable with that of noble metals. Such catalysts include Co-Mn [24], Cu-Co [28] and Co-Fe [25][26][27]. It is important to note that, because of the weak performances of Cr 2 O 3 catalyst compared to other single oxide presented in this review, in addition to highly toxicity, we have restricted the application of Cr-based catalysts to low operation temperatures.…”

“…Because cobalt ferrite binary oxide with high Co concentration (Co 2.1 Fe 0.9 O 4 ) showed very interesting catalytic performance against the deep oxidation of C 3 H 6 , n-C 4 H 8 and DME, Kouotou et al [26] explored the catalytic activity of the same material, but with low Co concentration (CoFe 2 O 4 ). Authors aimed to compare the performances of CoFe 2 O 4 (low cobalt content) versus Co 2.1 Fe 0.9 O 4 (high cobalt content) from recent investigation toward catalytic oxidation of CO, DME, C 3 H 6 and n-C 4 H 8 .…”

“…Among TMOs, single and mixed oxides, such as manganese and cobalt oxides, perovskites, zirconia-based catalysts, have been claimed for their effectiveness in VOCs oxidation [14][15][16][17][18][19]. In particular, Co 3 O 4 -based catalysts, which have been studied several decades ago regarding the high activity for CO and VOCs oxidation [20][21][22], have received again considerable attention in the recent years [23][24][25][26][27][28]. However, the physico-chemical and catalytic properties of TMOs thin films can be modulated with respect to the morphology, surface and bulk composition as well as metallic ratio, which are strongly dependent upon the preparation approaches and experimental conditions [29][30][31][32].…”

“…In recent years, great efforts have been made to the development of efficient TMOs synthesis methods, including sol-gel [33], thermal decomposition [34], hydrothermal synthesis, electrodeposition [35] and pulsed spray evaporation chemical vapor deposition (PSE-CVD) [23][24][25][26][27][28]. Among these techniques, PSE-CVD shows the benefit of being a reliable one-pot method for the growth of complex oxides with controlled composition, since most of the functional oxides contain more than two elements in their structures and further tuning of their properties requires controlled doping ratio.…”