Temperature-programmed Reduction Results Research Articles

Unravelling cobalt incorporation in Ca- and Sr-rich perovskites: How symmetry shapes the phases

The Ca-rich and Sr-rich stoichiometric and non-stoichiometric materials were obtained by the modified citrate method. After calcination at 900 °C, materials were characterized in terms of structure, microstructure and reducibility in an H2-containing atmosphere. The diffractometric data did not confirm the presence of Co-originated phases. Co K-edge and Ti K-edge were recorded and analyzed for a deeper description of the structural properties of materials, mainly the influence of non-stoichiometry on the effectiveness of Co incorporation into the perovskite systems. The X-ray absorption near edge structure study combined with temperature programmed reduction results indicated the presence of CoTiO3 and cobalt oxides phases for Ca-rich and Sr-rich. This approach also allowed to observe that non-stoichiometry in Sr-rich materials results in a lower amount of cobalt incorporated into the perovskite structure and a higher amount of Co3O4 formed. Additionally, for Ca-rich materials, XANES spectra indicated a higher amount of Co in the Ti sublattice and confirmed the higher Co2+/Co3+ ratio than in the case of Sr-rich materials.

Investigation of microstructure evolution and redox behavior of Ni-GDC cermet by cyclic re-oxidation in CO2

The microstructure and reactivity of Ni-GDC cermet under cyclic oxidation in CO2 conditions were investigated using temperature-programmed reduction (TPR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The XRD results revealed that NiO was formed during the re-oxidation process in CO2. SEM and TPR results demonstrated that nanostructured NiO aggregates were formed on the surface of the sample after being re-oxidized at 400 °C for 1200 min, resulting in an α peak with high reduction activity and a conversion of only 16% from Ni to NiO. In contrast, the samples re-oxidized at 600 °C for 600 min and 800 °C for 240 min were completely oxidized, resulting in reconstructed and sintered NiO with larger particle size, and a β peak with lower reactivity and a conversion of 100%. Redox cycling was further conducted on completely oxidized samples, which showed a decrease in β peak temperature from the first to seventh cycle. The migration and redistribution of sintered NiO towards the exterior were confirmed by comparing SEM images after the first and fourth cycles, which favored an increase in the reactive area. Therefore, this study reveals that lower re-oxidation temperatures (≤400 °C) and an appropriate increase in redox cycles are beneficial for forming surficial nanostructures while hindering the formation of large sintered NiO particles.

Characterization of Ag/α-Al2O3 olefin epoxidation catalysts containing promoters and co-promoters using pulse hydrogen titration methods

A series of Cs and Cs + Re promoted 12 wt% Ag/α-Al2O3 catalysts were prepared and characterized by H2 pulse titration of O-precovered Ag to measure active Ag site concentrations. Temperature programmed reduction (TPR) at temperatures up to 500 °C was performed on α-Al2O3 supported 3–4 wt% Cs, Re, or Mo only catalysts to confirm the metal–oxygen bonds of the promoters were not reactive during titration of Ag-O surface at 170 °C; absence of H2 uptake during H2 titration for these samples confirmed the TPR results. H2 pulse titration results of 0 to 7.5 μmol Cs promoted, 12 wt% Ag/α-Al2O3 catalysts showed non-preferential deposition of Cs on Ag and α-Al2O3 surfaces. However, when Cs (2.6 μmol)–12 wt% Ag/α-Al2O3 catalyst was promoted with ≥1.3 μmol of Re, titration results showed preferential deposition of Re on Ag sites, presumably to lower overall surface free energy of the Re-Ag-Al2O3 system.

Experimental and DFT research for the effects of sodium on the heterogeneous reaction between NO and semichar derived fromO2/CO2 pretreatments

The excessive emission of NO is endangering the ecological environment and the health of humans. In-depth research on the reduction mechanisms of NO is crucial to regulating NO emissions. In this research, the influence of sodium on the heterogeneous reaction of NO by semichar derived from O2/CO2 pretreatments were investigated through the experimental and density functional theory (DFT) method. According to the results of atomic dipole corrected Hirshfeld atomic charge (ADCH), the additional Na and oxygen-containing compound altered the semichar's charge distribution of. The additional Na weakened the positive effects of the marginal hydrogen. And the charge of the carbon, which was attached to the phenol group, changed from negative to positive due to the strong electron-trapping ability of the phenol group. The energy potential diagrams between NO and semichars derived from O2/CO2 pretreatments without/with sodium addition reflected that sodium was beneficial to reduce NO. Compared with pure O2/CO2 pretreatments, the additional sodium decreased the energy gap of the NO reduction by 144.68 kJ/mol. On the other hand, the temperature-programmed reduction (TPR) results were performed to identify the accuracy of the calculation results. The experimental results illustrated that adding sodium enhanced the NO reducibility of semichar, expressing great consistency with the theoretical results.

Low-temperature NH3-SCR performance of a novel Chlorella@Mn composite denitrification catalyst

The synthesis process of conventional Mn-based denitrification catalysts is relatively complex and expensive. In this paper, a resource application of chlorella was proposed, and a Chlorella@Mn composite denitrification catalyst was innovatively synthesized by electrostatic interaction. The Chlorella@Mn composite denitrification catalyst prepared under the optimal conditions (0.54 g/L Mn2+ concentration, 20 million chlorellas/mL concentration, 450°C calcination temperature) exhibited a well-developed pore structure and large specific surface area (122 m2/g). Compared with MnOx alone, the Chlorella@Mn composite catalyst achieved superior performance, with ∼100% NH3 selective catalytic reduction (NH3-SCR) denitrification activity at 100-225°C. The results of NH3 temperature-programmed desorption (NH3-TPD) and H2 temperature-programmed reduction (H2-TPR) showed that the catalyst had strong acid sites and good redox properties. Zeta potential testing showed that the electronegativity of the chlorella cell surface could be used to enrich with Mn2+. X-ray photoelectron spectroscopy (XPS) confirmed that Chlorella@Mn had a high content of Mn3+ and surface chemisorbed oxygen. In-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) experimental results showed that both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms play a role in the denitrification process on the surface of the Chlorella@Mn catalyst, where the main intermediate nitrate species is monodentate nitrite. The presence of SO2 promoted the generation and strengthening of Brønsted acid sites, but also generated more sulfate species on the surface, thereby reducing the denitrification activity of the Chlorella@Mn catalyst. The Chlorella@Mn composite catalyst had the characteristics of short preparation time, simple process and low cost, making it promising for industrial application.

Effect of the NiO particle size on the activity of Mo/HZSM-5 catalyst physically mixed with NiO in methane dehydroaromatization

Methane dehydroaromatization is an effective reaction that directly converts methane to benzene, toluene, xylene (BTX), and hydrogen in a non-oxidative atmosphere. Our previous study reported that when commercial NiO was added to Mo/HZSM-5 via a simple physical mixing method, the methane conversion and BTX selectivity were significantly improved. In this study, the efficiency of NiO particles with various sizes (4, 22, 36, 45, and 101 nm) as promoters was evaluated, and it was found that NiO(36 nm) has the optimum size for enhancing the activity of Mo/HZSM-5. The results of temperature-programmed reduction of methane, X-ray diffraction, transmission electron microscopy, and CO chemisorption revealed that among the samples analyzed, NiO(36 nm)-Mo/HZSM-5 had the highest dispersion of MoCx active sites because it had the lowest reduction temperature for NiO and MoOx. When the NiO particle size was smaller than 22 nm, the formation of inactive NiMoO4 was preferred, which caused the severe agglomeration and low dispersion of MoCx.

Activation of the MoS2 Basal Plane to Enhance CO Hydrogenation to Methane Activity Through Increasing S Vacancies.

The active site of MoS2 is usually located at the edge of crystalline MoS2, which has a lower proportion than that from the basal plane, limiting the hydrogenation activity. Therefore, activating the basal plane of MoS2 is expected to greatly enhance the hydrogenation activity. Herein, we prepared a series of MoS2 catalysts by acidolysis of ammonium tetrathiomolybdate and subsequently pyrolyzing at high temperature with different atmospheres. Through analysis, we found that the prepared MoS2 catalysts were curved, which was different from commercial MoS2. Through X-ray diffraction, transmission electron microscopy, and Raman and X-ray photoelectron spectroscopy characterization, it was found that the MoS2 catalyst pyrolyzed under a N2 atmosphere had a larger number of S-vacancies than the MoS2 catalysts under a H2 atmosphere. In addition, temperature-programmed reduction results showed that the Mo-S bond energy was decreased with the increasing content of S-vacancies, which might be related to bending. Sulfur-resistant methanation results indicated that the curved MoS2 exhibited increased CO conversion with the increasing S vacancies. Furthermore, density functional theory calculation was used to simulate the generation of S vacancy and numbers of S vacancies. It was found that with the generation of S vacancy, three unsaturated coordination Mo atoms were exposed around one S vacancy and became new active sites, resulting in enhanced activity. What is more, the higher methanation activity was attributed not only from more S vacancies but also from the decreased activation energy for CO hydrogenation activation.

Promotion Effect of Cu for CO Oxidation on Ceria Supported PdxCuy Bimetallic Catalysts

The surface composition and structure of bimetallic catalysts are important for the catalytic performance. In this work, PdxCuy/CeO2 catalysts with various Pd/Cu ratios were prepared and characterized by surface-sensitive techniques combined with ex-situ pretreatment. CO oxidation was used to correlate the surface composition with the catalytic performance. Compared with the monometallic Pd/CeO2 and Cu/CeO2, the PdxCuy/CeO2 bimetallic catalysts with a small amount of Cu show much higher CO oxidation activities. High-sensitivity low-energy ion scattering spectroscopy (HS-LEIS) combinded with X-ray photoelelctron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR) results indicate that adding a small amount of Cu can efficiently promote the surface dispersion of Pd and affect the redox properties, whereas the CO oxidation activity is significantly suppresssed after adding a larger amount of Cu, which may be mainly induced by the preference for surface segregation of Cu that blocks the active site of Pd.

Tuning the Pt species on Nb2O5 by support-induced modification in the photocatalytic transfer hydrogenation of phenylacetylene

Herein, we reported the tuning of dominant products in the photocatalytic hydrogen transfer reaction over Pt/Nb2O5 photocatalysts, using a support-induced modification strategy. In the photocatalytic conversion of phenylacetylene with ethanol as a probe reaction, the dominant product was styrene over Pt/2D Nb2O5 nanoplates; in contrast, H2 was the main product over the Pt/bulk Nb2O5. Compared to the metallic Pt species over bulk Nb2O5, the positively charged Pt (Ptδ+) species over 2D Nb2O5 nanoplates contributed to the reduction of phenylacetylene, which was revealed by CO adsorbed Fourier transform infrared spectra. Furthermore, the present Ptδ+ species were due to the formation of Ptδ+–O–Nb structure via oxygen transfer of 2D Nb2O5 nanoplates, which was verified by the results of X-ray photoelectron spectra and H2 temperature-programmed reduction. This work sheds light on the design and application of Nb-based catalysts in the transfer hydrogenation of organics in photocatalysis.

Methane combustion over mesoporous cobalt oxide catalysts: Effects of acid treatment

Mesoporous cobalt oxide catalysts synthesized via a nano-replication method were applied to the methane combustion reaction. In addition, samples were treated with different concentrations of nitric acid to modify their surface structures and chemistry. A significant enhancement in the methane oxidation activity was observed for the acid-treated catalysts compared to the pristine catalyst, and the properties of the acid-treated catalyst were investigated in detail using various characterization techniques. In particular, transmission and scanning electron microscopy images revealed a roughening in the surface morphology of the acid-treated catalysts. Meanwhile, the H2 temperature-programmed reduction results showed that the reducibility of the cobalt oxides was enhanced by the acid treatment. In addition, O2 temperature-programmed desorption and X-ray photoelectron spectroscopy analyses revealed that the acid-treated catalysts contained larger amounts of surface chemisorbed oxygen than the pristine catalyst, which may explain the enhanced reducibility and oxidation activity of the acid-treated catalysts. In conclusion, simple acid treatment is a useful post-treatment method for the synthesis of highly active bulk oxide catalysts for the methane combustion reaction.

Hydrogen separation using polybenzimidazole membrane with palladium nanoparticles stabilized by polyvinylpyrrolidone

An innovation in hydrogen (H2) selective membrane holds the substantial key of H2 economy. Polymers are the most practical and economical material for membrane fabrication, but their application in H2 separation is always constrained within the selectivity-permeability “trade-off” boundary. The expensive palladium (Pd) thin films offer higher selectivity by facilitating the dissociation, diffusion and re-association of H2 gas. This work reports on the incorporation of Pd nanoparticles into polybenzimidazole (PBI) membranes to surpass the mentioned limitations. Pd nanoparticles were synthesized and stabilized in the inversed microemulsion of polyvinylpyrrolidone (PVP) prior to blending. The X-ray diffraction and energy dispersive X-ray results proved the presence of Pd nanoparticles blended into PBI membrane with dense structure. The agglomerated and the stabilized Pd nanoparticles PBI matrix behaved very differently in H2 adsorption at the rising temperature as shown in temperature-programmed reduction results. The ideal H2/CO2 selectivity of PBI membrane with 1 wt% of Pd nanoparticles was improved by 49% compared to the PBI membrane at 150°C. This membrane surpassed the upper bound Robeson plot at 300°C (ideal H2/CO2 selectivity of 83.57; H2 permeability of 151.73 Barrer) and the H2 permeation could be correlated with Van't Hoff-Arrhenius equation.

Highly active and water tolerant Pt/MFe2O4 (M = Co and Ni) catalysts for low temperature CO oxidation

Pt supported on CoFe2O4 and NiFe2O4 spinel oxides were much more active for low temperature CO oxidation compared to those supported on monometallic oxides (i.e. Co3O4, Fe2O3 and NiO). The Pt/CoFe2O4 catalyst gave the best performance, with a turnover frequency of 0.27 s−1 at 50 ℃, which was three times as high as that on the Pt/Fe2O3. The interaction between Pt and the spinel oxide facilitated the activation of the oxygen species as evidenced by the H2 temperature programmed reduction results, and weakened the adsorption strength of CO on the Pt atoms as revealed by the in situ diffuse reflectance infrared Fourier transform spectroscopy results and kinetic investigation. These facts accounted for the enhanced reactivity. Moreover, the catalysts exhibited excellent water tolerance, which maintained activity even under 10 vol.% water vapor in the feed stock. Therefore, these catalysts are promising for practical applications.

What Are the Best Active Sites for CO2 Methanation over Ni/CeO2?

We examined active sites for CO₂ methanation over Ni/CeO₂ catalysts prepared by a wet impregnation method. Four types of Ni/CeO₂ with Ni loadings of 1, 3, 5, and 10 wt % were used in this study, assuming that the Ni sites are well dispersed in the catalysts when changing the Ni loading. According to powder X-ray diffraction and scanning transmission electron microscopy, the low-loading catalysts (1 and 3 wt %) consist mainly of Ni–Ce mixed oxides. The results of temperature-programmed reduction by H₂ suggested that the Ni–Ce mixed oxides under reducing conditions contain oxygen vacancies (Ni–Vₒₓ–Ce). Note that the CO₂ conversion rate was proportional to the Ni loading, which probably means that Ni–Vₒₓ–Ce sites on the Ni–Ce mixed oxides are active in CO₂ conversion. In contrast, when the Ni loading was high (5 and 10 wt %), the catalysts possessed many metallic Ni nanoparticles supported on CeO₂ and Ni–Ce mixed oxides. Because the turnover frequencies of CO methanation for 5 and 10 wt % Ni/CeO₂ were identical, the presence of a metallic Ni surface could be essential for activation in CO methanation. We focused on the fact that the CO₂ conversion rate was not related to the number of oxygen vacancies on CeO₂ (Ce–Vₒₓ–Ce) but was related to the number of the Ni–Vₒₓ–Ce sites. Hence, the formation of Ni–Vₒₓ–Ce sites (CO production via the reverse water-gas shift reaction) and the exposure of metallic Ni sites (methanation of the thus-formed CO) are essential for CO₂ methanation. Although it has been known that oxygen vacant sites on Ni/CeO₂ catalysts are important for the catalytic activity, this study suggested anew that there are two types of the sites, Ce–Vₒₓ–Ce and Ni–Vₒₓ–Ce. Furthermore, it was clarified that the latter oxygen defect is important for CO₂ methanation.

Effect of FSP-inserted Cu on Physicochemical Properties of Cu/Al2O3 Catalyst

The copper inserted on Cu/Al2O3 catalysts with various Cu loading (10-40 wt%) were synthesized via flame spray pyrolysis (FSP). These catalysts were characterized using X-ray diffraction (XRD), N2 physisorption, temperature programmed reduction (TPR) and X-ray absorption near edge spectroscopy (XANES). The XRD results confirmed the formation of copper aluminate spinel (CuAl2O4) on the FSP-inserted Cu catalyst. The CuO crystallite size of the Cu/Al2O3 catalysts was increased with increasing Cu loading during the flame spray pyrolysis step. The incorporation of copper and aluminum precursors during the flame spray pyrolysis step can inhibit the growth of Al2O3 particles resulting in higher BET surface area and smaller particle size than pure Al2O3 support. The data from TPR and XANES results can predict the ratio of CuO and CuAl2O4 in the FSP-made support. Less than 20 wt% loading of the FSP-inserted Cu showed high concentration of CuAl2O4 phase in the FSP-made material. The composition of CuO and CuAl2O4 phase can be controlled by varying Cu loading in flame spray pyrolysis step. This is a promising alternative way to synthesize the desired catalyst. An example was the catalytic testing of the selective hydrogenolysis of glycerol. The presence of both CuO and CuAl2O4 phases in the Cu/Al2O3 catalyst enhanced the catalytic activity and promoted the selectivity to acetol product. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Steam reforming of liquefied petroleum gas using catalysts supported on ceria-silica

Hydrogen production from steam reforming of liquefied petroleum gas (SR-LPG) process was studied over nickel, platinum, rhodium, and ruthenium-based catalysts supported on CeO2–SiO2 (CS). BET surface area, X-ray diffraction (XRD), temperature programmed reduction (TPR) and X-ray absorption near edge spectroscopy (XANES) techniques were used to characterize the samples. The catalytic activity and stability of the samples during SR-LPG were measured at 400 °C and 600 °C, respectively. XRD data were used to estimate the average crystallite size of ceria, which was small in all samples. For Pt and Rh containing samples, no diffraction peaks related to the metals were identified, which suggests high dispersion of these metals on the support. TPR and XANES experimental results showed that the addition of metals promoted the reduction of ceria. The order of catalyst activity for during SR-LPG at 400 °C was: Rh/CS » Pt/CS > Ru/CS » Ni/CS. Pt/CS and Rh/CS samples exhibited lower deactivation than nickel and ruthenium catalysts for SR-LPG at 600 °C during 24 h. Catalysts deactivation was mainly due to carbon deposition. In situ XRD data collected during SR-LPG at 600 °C revealed small increases in the mean particle sizes of Ni(0) and Ru (0), which could be pointed out as an additional cause for faster deactivation of the Ru/CS and Ni/CS catalysts.

Effect of Cobalt on Nickel Oxide Toward Reduction Behaviour in Hydrogen and Carbon Monoxide Atmosphere

The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydrogen (H2) in nitrogen (20%, v/v) and carbon monoxide (CO) in nitrogen (40%, v/v) atmospheres have been investigated by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Co doped and undoped nickel oxide in both reductants proceed in one step reduction (NiO → Ni) without intermediate. TPR results also suggested that by adding Co metal into NiO, the reduction to metallic Ni by both reductant gaseous give different intensity of the peak. The reduction process of Co and undoped NiO become faster when H2 was used as a reductant. Furthermore, in H2 atmosphere, Co-NiO give complete reduction to metallic Ni at 700 °C. Meanwhile, XRD analysis indicated that NiO without Co composed better crystallite phases of NiO with higher intensity.

In Situ Investigations on the Facile Synthesis and Catalytic Performance of CeO2-Pt/Al2O3 Catalyst

Ceria-modified Pt/Al2O3 catalyst has been commonly prepared by the impregnation of platinum on ceria-modified alumina and widely applied in the chemical industry and automotive industry. The in situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS), and thermogravimetric (TG) analysis techniques were employed to investigate the typical mechanisms of the bis(ethanolammonium)hexahydroxyplatinate(IV) and cerium nitrate decomposition catalyzed by Ptδ+ species for the facile synthesis of CeO2-Pt/Al2O3 catalyst. It was found that Pt4+-catalyzed decomposition of cerium nitrate leads to the higher dispersity of ceria and forming more active oxygen species, on the basis of X-ray diffraction (XRD) and H2 temperature-programmed reduction (H2-TPR) results. The in situ activity measurements were also performed to investigate the reaction mechanisms and the specific activities for the catalytic CO, NO, C3H6 and C3H8 co-oxidation. The results indicate that undesirable N2O by-product is formed by the selective catalytic reduction (SCR) of NO by C3H6 below 350 °C. The cerium addition effectively improves the activity of catalytic oxidation, but exhibits an increased N2O yield, due to the increased reducibility.

Controlled synthesis of CeO2 nanorods and their promotional effect on catalytic activity and aging resistibility for diesel soot oxidation

Nanostructure of catalysts plays a critical role in catalytic activity and durability. Herein, a ceria nanorod catalyst, CeO2(NR), was designed and synthesized, and the relationships between nanostructure and catalytic activity as well as aging resistibility were investigated. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction results indicate that the nanorod structure of CeO2(NR) can be well maintained after aging at 900 °C for 8 h and can prevent the excessive expansion of crystals during high-temperature aging. X-ray photoelectron spectroscopy and hydrogen temperature-programmed reduction results suggest that the CeO2(NR) nanorod has distinctly more oxygen vacancies than the CeO2 nanoparticle; moreover the nanorod structure of CeO2(NR) and CeO2(NR)-A can enhance the lattice oxygen mobility and contribute to the spillover of lattice oxygen to form surface active oxygen during high temperature reaction. Finally, the catalytic activity tests indicate that the synthesized CeO2(NR) nanorod catalyst displays significantly better soot purification efficiency and intrinsic activity for soot oxidation; more than that, this superior catalytic activity of CeO2(NR) is well maintained after high-temperature thermal aging. Thus, this work suggests that the nanorod structure of ceria-based catalysts plays a key role in enhancing aging resistibility and catalytic soot oxidation activity.

Highly Active Bulk Mo(W)S2 Hydrotreating Catalysts Synthesized by Etching out of the Carrier from Supported Mono- and Bimetallic Sulfides

A bulk MoWS2 catalyst has been synthesized by acid etching of the carrier from the supported MoWS2/Al2O3 catalyst obtained on the basis of the mixed bimetallic heteropoly acid (HPA) H4[SiMo3W9O40]. As reference samples, monometallic MoS2 and WS2 catalysts have been prepared from the corresponding supported analogues, as well as a Mo + WS2 sample based on a mechanical mixture of monometallic HPA in the atomic ratio of Mo/W = 1/3. The catalytic properties of the synthesized catalysts have been studied in model reactions of hydrodesulfurization (HDS) of dibenzthiophene (DBT) and hydrogenation (HYD) of naphthalene in a flow unit. It has been shown that the catalytic activity of the samples in both the DBT HDS and naphthalene HYD reactions increases in the following order: MoS2 < WS2 < Mo + WS2$$ \ll $$ MoWS2. It has been found that the bulk tungsten-containing catalysts exhibit higher specific catalytic activity than the supported counterparts. Increased values of hydrogen uptake according to the results of hydrogen temperature-programmed reduction for the bulk catalysts indicate an increase in the number of active sites and the formation of a more effective active phase compared to supported catalysts.

Influence of Cerium on the Reduction Behaviour of Iron Oxide by Using Carbon Monoxide: TPR and Kinetic Studies

Reduction of iron oxide is one of the most studied topics owing to the importance of iron/steel industry and also has been used as a precursor and active component in a number of important chemical processes. The interaction between iron oxide and other metal additive have gained interest in the past two decades due to the ability on enhancing the reduction performance of the iron oxide. Therefore, this study was undertaken to investigate the influence of cerium on the reduction behaviours of iron oxide by (10%, v/v) carbon monoxide in nitrogen. The cerium doped (Ce-Fe2O3) and non-doped iron oxide reduction behaviour and the kinetic studies have been studied by temperature programmed reduction (TPR) and the phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD) while the activation energy values were calculated from Arrhenius equation using Wimmer’s method. TPR results indicate that the reduction of doped and undoped iron oxide proceeds in three steps reduction (Fe2O3 ? Fe3O4 ? FeO ? Fe), while doped iron oxide showed a large shifted towards lower temperature especially in the transition steps of FeO ? Fe. Furthermore, TPR results also suggested that by adding Ce metal into iron oxide the reduction of metal iron completed at lower temperature (700 ?C) compared to non-doped iron oxide (900 ?C). Meanwhile, XRD analysis indicated that doped iron oxide composed of Fe2O3 and a small amount of FeCe2O4. The increase in the rates of iron oxide reduction may relate to the presence of cerium species in the formed of FeCe2O4 and was confirmed by the decrease in the activation energy regarding to all transition phases (Fe2O3 ? Fe3O4 ? FeO ? Fe) during the reduction process