Fe-Co Oxides Research Articles

MOF-derived Co3O4@Co-Fe oxide double-shelled nanocages as multi-functional specific peroxidase-like nanozyme catalysts for chemo/biosensing and dye degradation

Nanozymes are attractive alternatives to natural enzymes due to their high stability and low cost. However, it is still a great challenge to acquire highly active, specific, and multi-functional nanozyme catalysts for chemo/biosensing and peroxymonosulfate (PMS) activation to degrade toxic dye pollutants. Metal-organic frameworks are attractive templates to construct multi-functional catalysts. Herein, Co3O4@Co-Fe oxide double-shelled nanocages (DSNCs) were prepared via anion-exchange combined with low-temperature pyrolysis by using ZIF-67 as a starting template. They maximized the advantages of a hollow nanostructure, acting as both nanoreactor and substrate channel, to mimic enzymes. This enables high peroxidase-like activity and very weak oxidase-like activity. The Km value of Co3O4@Co-Fe oxide DSNCs for H2O2 was 1.38 and 3.33-fold lower than those of single-shelled Co-Fe oxide and Co3O4 nanozymes, respectively. The high peroxidase-like activity of Co3O4@Co-Fe oxide DSNCs enabled H2O2 linear detection over the range 0.02 to 600 μM, with a detection limit of 20 nM. When coupled with the acetylcholinesterase/acetylthiocholine cascade enzymatic reaction, we proposed an ultra-sensitive colorimetric platform for acetylcholinesterase activity screening in the linear range over 8 × 10−4–1 mU mL−1, with a detection limit of 2 × 10−4 mU mL−1. The Co3O4@Co-Fe oxide DSNCs can active PMS to degrade 99.1% of acid fuchsin within 20 min, along with good reusability over ten-cycle run. The kinetics of 15 mg L−1 acid fuchsin degradation was 0.176 min−1 at 25 °C with 300 mg L−1 PMS and 150 mg L−1 DSNCs. This work details the attractive applications of DSNCs for chemo/biosensing and dye degradation.

Accelerative oxygen evolution by Cu-doping into Fe-Co oxides

Low overpotentials of 256, 271, and 226 mV at 10 mA cm−2can be achieved over FeCoCuOxsupported on a GCE, a Pt electrode, and Ni foam, respectively, in an alkaline electrolyte.

Effect of sintering on morphology and magnetic properties of Fe-Co nano-rods prepared by wet chemical route

Ferromagnetic Fe-Co oxide nano-rods with high coercivity have been synthesized using wet chemical method. Samples were sintered in hydrogen and nitrogen atmosphere at different temperatures. Structural and morphological studies were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) and transmission electron microscopy (TEM) analysis. The magnetic properties of the particles were measured by a vibrating sample magnetometer (VSM) with a varying magnetic field. XRD pattern demonstrates the presence of pure α-Fe phase in the samples sintered in H2 atmosphere while the presence of Co substituted oxide phases in the samples sintered in N2 atmosphere. SEM micrograph of samples sintered in N2 demonstrates the growth of plate like morphology; such growth was not observed when the samples were sintered in H2atmosphere. Non homogeneous growth of nano-rods was obtained when sintered in N2 atm at 550 ºC whereas homogeneous growth was obtained when sintered in N2 atm at 900 ºC. VSM measurement gives the higher amount of coercivity in the samples sintered in N2 which could be attributed to the rod shape of oxide phase which has high L/D ratio and helps in increasing the anisotropy and hence the coercivity. The higher amount of magnetization value than as prepared samples was observed in samples sintered in H2 atmosphere.

Preparation of Co-Fe oxides immobilized on carbon paper using water-dispersible Prussian-blue analog nanoparticles and their oxygen evolution reaction (OER) catalytic activities

Carbon paper (CP) is one of the most promising metal-free gas-diffusion electrodes for fabricating sustainable energy-conversion devices such as metal-air secondary batteries using the oxygen reduction reaction (ORR) and CO2-reforming systems via the electrochemical CO2 reduction reaction (CO2RR). The common counterpart reaction for ORR and CO2RR is the oxygen evolution reaction (OER) from water. The low-overpotential OER catalyzed by nanoparticles (NPs) immobilized on CP has attracted attention for integration in energy-conversion devices. Earth-abundant and low-cost 3d transition metals have been intensively explored as OER catalysts. In this study, we have successfully prepared Fe-Co Prussian blue analog (PBA) NPs with the formulae of Fe1-xCox[Fe(CN)6]0.67·nH2O and Fe1-yCoy[Co(CN)6]0.67·mH2O, and the Fe-Co PBA NPs are dispersed into water by surface modification using [Fe(CN)6]4−. By a simple drop-coating method, the Fe-Co PBA NPs are immobilized on CP and thermally decomposed into Fe-Co oxides at 400 °C. The OER overpotentials of the Fe-Co oxides are gradually decreased by increasing the Co composition ratios, and the lowest overpotential is 0.46 V vs. RHE at 10 mA/cm2 in y = 0.6.

Microstructure, Formation, and Diffusion Kinetics of Multilayered Oxides Formed on a Co-W Electroplated Ferritic Stainless Steel Followed by Oxidation Treatment

Numerous attempts have been made to improve the oxidation resistance and electrical conductivity of the interconnectors in solid oxide fuel cells. A Co-W alloy coating on ferritic stainless steel has attracted attention because the Co-W oxide layer formed by the oxidation treatment of the Co-W alloy coating has proven effective in reducing the outward diffusion of Cr and improving oxidation resistance. This study was designed to elucidate the formation kinetics and diffusion barrier mechanism of the Co-W coating. After oxidation in air at 750 °C, a dense, multilayered oxide formed, comprising (from the stainless steel substrate to the outer layer) Cr oxide, Cr-Fe-Co oxide, Co-W oxide, Co-Fe oxide, and Co oxide layers. The CoWO4 layer and neighboring oxide layers were carefully analyzed by scanning electron microscopy and transmission electron microscopy, which revealed that the innermost Cr2O3 layer grows via the reaction between Cr in the substrate and inward-diffusing oxygen, whereas outward diffusion of Fe and Co is involved in the formation and growth of (Co,Fe)3O4 and Co3O4. Analysis by electron energy-loss spectroscopy confirmed the absence of trivalent cations (Co3+, Fe3+, and Cr3+) and the presence of Fe2+ ions in the CoWO4 layer; thus, CoWO4 functions as a selective diffusion barrier to trivalent cations as hypothesized.

CeO2 nanorods supported M–Co bimetallic oxides (M = Fe, Ni, Cu) for catalytic CO and C3H8 oxidation

Supported bimetallic catalysts with rational compositions and structural design have attracted great interest, due to the tunable structural orientation (alloy or intermetallic compound and core-shell structure etc.), synergetic effects, and combined properties related to the presence of two individual metals. In this study, 10 wt% Fe-Co, Ni-Co and Cu-Co bimetallic oxides with 1:2 atomic ratio (FeCo2Ox, NiCo2Ox and CuCo2Ox) were deposited onto CeO2 nanorods (CeO2NR) via a hydrothermal-assisted precipitation-deposition method. The bimetallic synergism effects, surface structure configuration and the metal (oxide)-support interactions were investigated. The catalysts were characterized by means of powder XRD, TEM, EDX, Raman spectroscopy, XPS, BET surface area, H2-TPR, O2 pulse chemisorption and O2-TPD. All the CeO2NR supported bimetallic catalysts show considerable low-temperature CO oxidation performance. And the catalytic activity toward CO oxidation follows the order: 10 wt% CuCo2Ox/CeO2NR (T50 = 95 °C and T90 = 148 °C) > 10 wt% FeCo2Ox/CeO2NR (T50 = 129 °C and T90 = 193 °C) > 10 wt% NiCo2Ox/CeO2NR (T50 = 147 °C and T90 = 196 °C). As for the catalytic oxidation of C3H8, all the designed catalysts show similar low-temperature performance, but the 10 wt% NiCo2Ox/CeO2NR catalyst exhibits the maximum C3H8 conversion above 330 °C. In addition, we also demonstrate the important role of oxygen storage capacity (OSC) of CeO2NR support and the impact of different oxygen species (physi-/chemisorbed oxygen, and bulk lattice oxygen) on the oxidation of CO and light hydrocarbons.

Cattle’ microbiocoenosis of rumen while various feed ultrafine particles release

Changes in the cattle’ microbiocenosis of the rumen directly impacted the animals’ productivity. And the main role here is played by the feeding type, the animal’s diet, with a predominance of certain components in different periods of cows housing, which create the necessary conditions for the existence and activity of symbiotic microflora, as well as the development of associated pathologies. Earlier detection of these errors will help to avoid many abnormalities of metabolic processes in the body and prevent the decline in the animals’ productive qualities. That is why it is relevant to study the effect of ultrafine particles on the composition of cattle’ microbiota of rumen. In this article, we analyzed the cattle’ bacterial microbiocenosis in response to the introduction of ultrafine particles (FeCo and silicon oxide SiO2 alloy) into their diet. It is revealed that these ultrafine particles do not have a significant qualitative change in cattle’ microflora of the rumen, but shift the bacterial communities balance towards those microorganisms that improve the food digestibility, which allows them to be recommended as food additives to improve the farm animals productivity.

General Synthesis of Mixed Semiconducting Metal Oxide Hollow Spheres with Tunable Compositions for Low-Temperature Chemiresistive Sensing

Metal oxide hollow spheres (MOHSs) with multicomponent metal elements exhibit intriguing properties due to the synergistic effects of different components. However, it remains a great challenge to develop a general method to synthesize multicomponent MOHSs due to the different hydrolysis and condensation rates of precursors for different metal oxides. Herein, we demonstrate a general strategy for the controllable synthesis of MOHSs with up to five metal elements by decomposition of metal-phenolic coordination polymers (MPCPs), which are prepared by chelation of tannic acid with various metal ions. After calcination to burn out the organic component and induce heterogeneous contraction of MPCPs, a series of MOHSs with multishell structure, high specific surface area (55-171 m2/g), and crystalline mesoporous framework are synthesized, including binary (Fe-Co, Ni-Zn, and Ni-Co oxides), ternary (Ni-Co-Mn and Ni-Co-Zn oxides), and quinary (Ni-Co-Fe-Cu-Zn oxides) MOHSs. The gas sensing nanodevices based on quinary MOHSs show much higher response (10.91) than those based on single component toward 50 ppm of ethanol at 80 °C with the response/recovery time of 85/160 s. The quinary oxides sensor also displays high selectivity toward ethanol against other interfering gases (e.g., methanol, formadehyde, toluene, methane, and hydrogen) and long-term stability (∼94.0% after 4 weeks), which are extremely favorable for practical applications.

Novel carbon based Fe-Co oxides derived from Prussian blue analogues activating peroxymonosulfate: Refractory drugs degradation without metal leaching

To meet the current challenges of removing refractory drugs from wastewater and groundwater, an efficient and environmentally friendly treatment process is desired. Herein, a novel magnetic composite of carbon-based Fe-Co oxide (MCFC) was fabricated from a Prussian blue analogue and graphene oxide by pyrolysis in nitrogen and then re-sintering in air. MCFC showed good performance for several kinds of refractory drugs (including 4-aminobenzoic acid ethyl ester (ABEE), sulfamethoxazole and acyclovir) degradation by activation peroxymonosulfate (PMS), without any detectable metal leaching, as an important green environmental remediation technology. A slight performance decrease of MCFC observed during the reuse, was able to be recovered by a simple thermal process. No metal ions dissolution and thermal regeneration was an important development on PMS activation catalyst. Degradation intermediates of a refractory drug, ABEE, were identified by liquid chromatography quadrupole time-of-flight mass spectrometry. The degradation pathways of ABEE were established, with intermediates being generated by the electrophilic/radical addition and the hydrogen abstraction. At last, PMS activation pathways was proposed as that PMS was activated by Co2+ and Fe2+ on the surface of MCFC, pyrrolic-N, pyridinic-N, and carbonyl groups, to form singlet oxygen (1O2), hydroxyl radicals (OH) and sulfate radicals (SO4−). The synergistic effects between the metal nanocrystals and nitrogen-doped carbon promoted the regeneration of the surface Fe2+ and Co2+, which resulted in F4C6G5-6N-4a showing excellent catalytic activity for PMS activation. Through the above combination of non-radical (1O2) and radical (SO4− and OH) processes, ABEE was degraded and mineralized. This work presents a promising green heterogeneous catalyst for the degradation of refractory drugs in municipal wastewater/groundwater by PMS activation.

Novel urchin-like FeCo oxide nanostructures supported carbon spheres as a highly sensitive sensor for hydrazine sensing application

Herein, we successfully fabricated a novel nanostructure based on hierarchical urchin-like FeCo oxide supported carbon spheres (FeCo Oxide/CSs) via a two-step hydrothermal method followed by a simple annealing step at 300 °C under air. It was found that such urchin-like FeCo Oxide/CSs structure exhibited superior catalytic activity towards hydrazine oxidation to CSs, Fe Oxide/CSs, Co Oxide/CSs, and FeCo Hydroxide/CSs material. In this regard, the FeCo Oxide/CSs displayed a wide linear detection range of 0.1–516.6 μM, low detection limit of 0.1 μM, and long-term stability. The material also showed good selectivity towards hydrazine detection in the presence of various interferences, such as uric acid, ascorbic acid, urea, dopamine, Na+, SO42−, K+, and Cl-. The excellent sensing performance of the FeCo Oxide/CSs was assumed to the unique hierarchical urchin structure with the high density and uniformity of nano-sized FeCo Oxide nanoneedles, which produced massive electroactive sites and enhanced charge transfer ability. The achieved results implied that the FeCo Oxide/CSs may be a great candidate for sensitive hydrazine detection.

Graphene aerogel encapsulated Fe-Co oxide nanocubes derived from Prussian blue analogue as integrated anode with enhanced Li-ion storage properties

Hybridizing metal oxides with three-dimensional graphene is highly desirable for improving the ability of lithium storage. Herein a general strategy was employed to fabricate nanocomposites containing heterometallic oxide and graphene aerogel (GA) for the first time, in which Prussian blue analogue (PBA) was selected as self-sacrificial template for the preparation of metal oxide. The Fe-Co oxide nanocubes in the composite were homogeneously encapsulated in the network of GA, and meanwhile acted spacers separating adjacent graphene sheets. The as-prepared self-standing Fe-Co oxide@GA composite was used directly as excellent integrated anode material of lithium-ion batteries. More importantly, the composite electrode delivered an outstanding cycle stability with a specific capacity of 947 mA h g−1 at 100 mA g−1 after 130 cycles. Such superior Li-ion storage ability originates from the hierarchically encapsulated architecture and the strong synergistic effect between metal oxide and GA. The interconnected network of GA significantly improves the conductivity of the whole electrode as well as provides the space for buffering volume change of metal oxides, whereas metal oxides strongly wrapped within graphene nanosheets contribute large specific capacity.

Cobalt-Iron Oxide Nanoarrays Supported on Carbon Fiber Paper with High Stability for Electrochemical Oxygen Evolution at Large Current Densities.

Here, we demonstrate that nonprecious CoFe-based oxide nanoarrays exhibit excellent electrocatalytic activity and superior stability for electrochemical oxygen evolution reaction (OER) at large current densities (>500 mA cm-2). Carbon fiber paper (CFP) with three-dimensional macroporous structure, excellent corrosion resistance, and high electrical properties is used as the support material to prevent surface passivation during the long-term process of OER. Through a facile method of hydrothermal synthesis and thermal treatment, vertically aligned arrays of spinel Co xFe3- xO4 nanostructures are homogeneously grown on CFP. The morphology and the Fe-doping content of the CoFe oxide nanoarrays can be controlled by the Fe3+ concentration in the precursor solution. The arrays of CoFe oxide nanosheets (NSs) grown on CFP (Co2.3Fe0.7O4-NSs/CFP) deliver lower Tafel slope (34.3 mV dec-1) than CoFe oxide nanowire (NW) arrays grown on CFP (Co2.7Fe0.3O4-NWs/CFP) in alkaline solution, owing to higher Fe-doping content and larger effective specific surface area. The Co2.3Fe0.7O4-NSs/CFP electrode exhibits excellent stability for OER at large current densities in alkaline solution. Moreover, the morphology and structure of CoFeO nanoarrays are well preserved after long-term testing, indicating the high stability for OER.

Metal-Organic Framework Hybrid-Assisted Formation of Co3 O4 /Co-Fe Oxide Double-Shelled Nanoboxes for Enhanced Oxygen Evolution.

Rational design of complex metal-organic framework (MOF) hybrid precursors offers a great opportunity to construct various functional nanostructures. Here, a novel MOF-hybrid-assisted strategy to synthesize Co3 O4 /Co-Fe oxide double-shelled nanoboxes is reported. In the first step, zeolitic imidazolate framework-67 (ZIF-67, a Co-based MOF)/Co-Fe Prussian blue analogue (PBA) yolk-shell nanocubes are formed via a facile anion-exchange reaction between ZIF-67 nanocube precursors and [Fe(CN)6 ]3- ions at room temperature. Subsequently, an annealing treatment is applied to prepare Co3 O4 /Co-Fe oxide double-shelled nanoboxes. Owing to the structural and compositional benefits, the as-derived Co3 O4 /Co-Fe oxide double-shelled nanoboxes exhibit enhanced electrocatalytic performance for oxygen evolution reaction in alkaline solution.

Hybrid crumpled graphene supported Fe-Co binary oxides nanoparticles for aqueous asymmetric supercapacitors

Asymmetric supercapacitors are considered promising energy storage devices due to their high applied voltage and corresponding high energy density. Herein, Fe-Co binary oxides nanoparticles loaded crumpled graphene (CGR) composites were prepared for use as the positive electrode material of asymmetric supercapacitors (ASC) using aerosol spray pyrolysis and post heat-treatment processes. The composites showed a crumpled paper like morphology and were around 1 µm in average diameter. Asymmetric electrode structures were fabricated using the composites as the positive electrode and CGR as the negative electrode. Electrochemical measurement of the ASC indicated excellent capacitive performance, which resulted in high energy density (36 W h kg−1) and long-term cycling stability after 2000 cycles at a current density of 1 A g–1.

High-Performance Transition Metal Phosphide Alloy Catalyst for Oxygen Evolution Reaction.

Oxygen evolution reaction (OER) is a pivotal process in many energy conversion and storage techniques, such as water splitting, regenerative fuel cells, and rechargeable metal-air batteries. The synthesis of stable, efficient, non-noble metal-based electrocatalysts for OER has been a long-standing challenge. In this work, a facile and scalable method to synthesize hollow and conductive iron-cobalt phosphide (Fe-Co-P) alloy nanostructures using an Fe-Co metal organic complex as a precursor is described. The Fe-Co-P alloy exhibits excellent OER activity with a specific current density of 10 mA/cm2 being achieved at an overpotential as low as 252 mV. The current density at 1.5 V (vs reversible hydrogen electrode) of the Fe-Co-P catalyst is 30.7 mA/cm2, which is more than 3 orders of magnitude greater than that obtained with state-of-the-art Fe-Co oxide catalysts. Our mechanistic experiments and theoretical analysis suggest that the electrochemical-induced high-valent iron stabilizes the cobalt in a low-valent state, leading to the simultaneous enhancement of activity and stability of the OER catalyst.

Electrochemical performances of iron-cobalt oxides nanoparticles loaded crumpled graphene for supercapacitor

Mixed transition metal oxides (MTMOs) have been explored as attractive electrode materials for supercapacitors owing to their higher electronic conductivity and larger specific capacitance compared with simple transition metal oxides. Among MTMOs, cobalt-based binary metal oxides such as Fe-Co oxides have emerged as alternative electrode materials for supercapacitors because they have the advantages of low cost, natural abundance, and environmental friendliness. Recently, graphene-based Fe-Co oxides composites have become of particular interest for their improved electrochemical performance of supercapacitors due to the synergetic effect of both materials. In this study, we present three-dimensional (3D) crumpled graphene (CGR) decorated with Fe-Co oxides nanoparticles to determine which molar ratio of Fe/Co can exhibit higher electrochemical performance. The Fe-Co oxides/CGR composites were synthesized in different molar ratios of Fe/Co via aerosol spray pyrolysis and post heat treatment. Sizes of Fe-Co oxides nanoparticles ranged from 5 to 10 nm when loaded onto 500 nm CGR. The electrochemical properties of the Fe-Co oxides/CGR composites with different molar ratios of Fe/Co were examined. The Fe-Co oxides/CGR electrodes fabricated at the Fe/Co ratio of 0.1 showed the highest performances in the capacitance and electrical conductivity among those electrodes with different molar ratios of Fe/Co.

Fast in situ synthesis of CoFe layered double hydroxide onto multi-layer graphene for electrochemical capacitors

Homogeneous CoFe layered double hydroxide (LDH) was in situ synthesized onto the surfaces of multi-layer graphene (MLG) based on π-π interaction method just for 1-h reaction. The morphology, crystal structure, and electrochemical properties of the composite were systematically studied. The results showed that crystalline CoFe-LDH grown onto MLG was composed of two layers. The bottom layer was parallel to graphene sheet to increase the contact with graphene. The external layer was vertically assembled to allow the easy immersion of electrolyte into the pores between CoFe-LDH sheets. When being tested as electrochemical capacitor electrode, the composite could deliver a specific capacitance of 882.5 F g−1 at a current density of 1 A g−1. When prolonging the reaction time to 3 h, homogeneous CoFe oxide nanoparticles with a size of about 5 nm would be formed on the surface of CoFe-LDH. Its specific capacitance decreased to 462.5 F g−1 at 1 A g−1, but its cycle stability and rate capability were both improved. All CoFe-LDH sheets were transformed into CoFe oxide nanoparticles when the reaction time reaches 10 h, resulting in a further decrease of specific capacitance to 82.5 F g−1. Thus, to obtain a high electrochemical performance, the reaction time should be controlled because the phases and morphologies of the products are dependent on it.

Polymer nanofilm-coated catalysis: An approach for enhancing water-resistance of Co-Fe oxide nano-catalysts under moisture-rich condition

Water-induced deactivation of the oxides catalysts (especially for the Co3O4-based catalysts) is a challenging problem. For this reason, highly effective, long-term stable, moisture-resistant polymer nanofilm-coated FeaCobOx catalysts were synthesized by a solid-phase method mediated with oxalic acid (OA)/ethlyene glycol (EG) for low-temperature CO oxidation. The effects of the Fe, OA and EG amounts and calcination temperature on the physicochemical and catalytic properties of the FeaCobOx catalysts were investigated by various characterization techniques. The results demonstrate that the FeaCobOx catalysts are structurally mesoporous, and nanostructured FeaCobOx and polymer nanofilm coating play major roles on their high catalytic activity and stability. The nanofilm-coated Fe3Co16Ox nanoparticles prepared under an optimized synthetic condition and calcined at 250°C possesses higher surface area (134m2/g), Co3+/Co2+ ratio (1.89) and oxygen vacancy (20.5%), and thus exhibits the excellent catalytic performance for CO oxidation, such as, T50 of −114°C under normal moisture (3–10ppm) and T50 of 47°C under moisture-rich (∼0.6vol.%) conditions. Remarkably, compared with the published results, its much-improved long-term catalytic stability (>1month) can be observed even at a very high moisture level (3.1vol.%) and relatively low temperature (90°C). The deactivation of the catalyst at lower temperature resulted from accumulated water and carbonates on the catalyst surface can also be substantially minimized, through the water vapor-resistant with the help of gas-permeable polymer nanofilm coating.

Improvement in the Water Tolerance of SiO2-Modified Semicoke Catalysts for the Low-Temperature NO + CO Reaction

Activated semicoke (ASC) was modified with 3 wt % SiO2 and loaded with Fe-Co mixed oxides. This prepared catalyst exhibited excellent denitrification (deNO) activity, even when the flue gas contained 10 vol % water vapor, from 150 to 300 °C. To understand the water resistance mechanism, the catalysts were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Raman, X-ray, Fourier-transform infrared, and UV–vis spectroscopies, and H2-temperature-programmed reduction, as well as NO and/or water adsorption testing. In addition, quantum mechanical calculations were performed. The results indicate that the SiO2 doped onto the semicoke surface repels both water and NO molecules. However, the repulsive force toward NO is smaller, resulting in the adsorption of NO on the surface, while the adsorption of water was reduced. The reduction in the quantity of adsorbed water improved the water tolerance of the catalysts significantly. The adsorption results demonstrate that, when the water adsorption was less than 0.345–0.442%, water vapor had no influence on the deNO activity of ASC supported catalysts.

High-temperature thermochemical energy storage based on redox reactions using Co-Fe and Mn-Fe mixed metal oxides

Metal oxides are potential materials for thermochemical heat storage via reversible endothermal/exothermal redox reactions, and among them, cobalt oxide and manganese oxide are attracting attention. The synthesis of mixed oxides is considered as a way to answer the drawbacks of pure metal oxides, such as slow reaction kinetics, loss-in-capacity over cycles or sintering issues, and the materials potential for thermochemical heat storage application needs to be assessed. This work proposes a study combining thermodynamic calculations and experimental measurements by simultaneous thermogravimetric analysis and calorimetry, in order to identify the impact of iron oxide addition to Co and Mn-based oxides. Fe addition decreased the redox activity and energy storage capacity of Co3O4/CoO, whereas the reaction rate, reversibility and cycling stability of Mn2O3/Mn3O4 was significantly enhanced with added Fe amounts above ~15mol%, and the energy storage capacity was slightly improved. The formation of a reactive cubic spinel explained the improved re-oxidation yield of Mn-based oxides that could be cycled between bixbyite and cubic spinel phases, whereas a low reactive tetragonal spinel phase showing poor re-oxidation was formed below 15mol% Fe. Thermodynamic equilibrium calculations predict accurately the behavior of both systems. The possibility to identify other suitable mixed oxides becomes conceivable, by enabling the selection of transition metal additives for tuning the redox properties of mixed metal oxides destined for thermochemical energy storage applications.