Studies on reduction of chromium doped iron oxide catalyst using hydrogen and various concentration of carbon monoxide

Saharuddin, Tengku Shafazila Tengku; Samsuri, Alinda; Salleh, Fairous; Othaman, Rizafizah; Kassim, Mohammad B.; Hisham, Mohamed Wahab Mohamed; Yarmo, Mohd Ambar

doi:10.1016/j.ijhydene.2016.08.151

Cited by 25 publications

(6 citation statements)

References 22 publications

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“…Note that this reduction event occurs about 75°C lower for the steel powder, something that is believed to be caused by the change in composition of the oxide layer. A comparable result has been shown in another study where reduction of iron oxide in hydrogen was found to be promoted by doping with chromium 11 . This could help explain the observed lower reduction temperature of the steel powder.…”

Section: Resultssupporting

confidence: 88%

“…A comparable result has been shown in another study where reduction of iron oxide in hydrogen was found to be promoted by doping with chromium. 11 This could help explain the observed lower reduction temperature of the steel powder. The magnitude of mass loss related to the reduction below 400 C for the steel powder is also slightly smaller, indicating either a slight difference in particle size distribution or oxide layer thickness, 10 although the oxide layer thicknesses on both water-atomized iron and steel powder are typically considered to be similar.…”

Section: Resultsmentioning

confidence: 96%

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Evolution of surface chemistry during sintering of water‐atomized iron and low‐alloyed steel powder

Wendel

Manchili

Cao

et al. 2020

Surface & Interface Analysis

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Water-atomized iron and steel powder is commonly used as the base material for powder metallurgy (PM) of ferrous components. The powder surface chemistry is characterized by a thin surface oxide layer and more thermodynamically stable oxide particulates whose extent, distribution, and composition change during the sintering cycle due to a complex set of oxidation-reduction reactions. In this study, the surface chemistry of iron and steel powder was investigated by combined surface and thermal analysis. The progressive reduction of oxides was studied using model sintering cycles in hydrogen atmospheres in a thermogravimetric (TG) setup, with experiments ended at intermediate steps (500-1300 C) of the heating stage. The surface chemistry of the samples was then investigated by means of X-ray photoelectron spectroscopy (XPS) to reveal changes that occurred during heating. The results show that reduction of the surface oxide layer occurs at relatively lower temperature for the steel powder, attributed to an influence of chromium, which is supported by a strong increase in Cr content immediately after oxide layer reduction. The reduction of the stable oxide particulates was shifted to higher temperatures, reflecting their higher thermodynamic stability. A complementary vacuum annealing treatment at 800 C was performed in a furnace directly connected to the XPS instrument allowing for sample transfer in vacuum. The results showed that Fe oxides were completely reduced, with segregation and growth of Cr and Mn oxides on the particle surfaces. This underlines the sequential reduction of oxides during sintering that reflects the thermodynamic stability and availability of oxide-forming elements.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 96%

Evolution of surface chemistry during sintering of water‐atomized iron and low‐alloyed steel powder

Wendel

Manchili

Cao

et al. 2020

Surface & Interface Analysis

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“…The first reduction peak of the Fe 2 O 3 sample located in the low-temperature region (402 °C) was assigned to the reduction of Fe 2 O 3 to Fe 3 O 4 , while the second reduction peak of Fe 2 O 3 in the high-temperature region (526 °C) was attributed to the reduction of Fe 3 O 4 to FeO. The third reduction peak of Fe 2 O 3 in the high-temperature region (594 °C) was assigned to the reduction of FeO to Fe. , In this study, when Ag nanoparticles were loaded on the Fe 2 O 3 surface, in addition to the reduction peaks of Fe 2 O 3 , two more peaks (178 and 440 °C) were observed, which can be attributed to AgO x . When Pd and PdAg alloy nanoparticles were loaded onto the surface of Fe 2 O 3 , low temperature peaks of Pd/Fe 2 O 3 (140 and 300 °C) and PdAg/Fe 2 O 3 (162 and 330 °C) were observed, which can be attributed to PdO x reduction and/or PdH x decomposition .…”

Section: Resultsmentioning

confidence: 57%

Efficient Catalytic Combustion of Cyclohexane over PdAg/Fe₂O₃ Catalysts under Low-Temperature Conditions: Establishing the Degradation Mechanism Using PTR-TOF-MS and in Situ DRIFTS

Wen

Guo

et al. 2022

ACS Appl. Mater. Interfaces

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Cyclohexane, a typical volatile organic compound (VOC), poses high risks to the environment and humans. Herein, synthesized PdAg/Fe2O3 catalysts exhibited exceptional catalytic performance for cyclohexane combustion at lower temperatures (50% mineralization temperature (T 50) of 199 °C, 90% mineralization temperature (T 90) of 315 °C) than Pd/Fe2O3 (T 50 of 262 °C, T 90 of 335 °C) and Fe2O3 (T 50 of 305 °C, T 90 of 360 °C). In addition, PdAg/Fe2O3 displayed enhanced stability by alloying Ag with Pd. The redox and acidity of the PdAg/Fe2O3 were studied by XPS, H2-TPR, and NH3-TPD. In situ diffuse reflectance infrared Fourier transform spectroscopy and proton-transfer-reaction time-of-flight mass spectrometry were applied to identify the intermediates formed on the catalyst surface and in the tail gas during oxidation, respectively. Results suggested that loading PdAg onto Fe2O3 significantly enhanced the adsorption and activation of oxygen and cyclohexane, oxidative dehydrogenation of cyclohexane to benzene, and catalytic cracking of cyclohexane to olefins at low temperatures. This in-depth study will benefit the design and application of efficient catalysts for the effective combustion of VOCs at low temperatures.

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“…Similar findings can be observed from studies regarding the effect of Cr. According to Saharuddin et al, [27] doping the hematite with chromium oxide enhances FeO x reduction. It should be emphasized that activation processes occurring at temperature range up to 400°C in the presence of water steam have practical consequences on properties and efficiency of industrial catalysts Fe-Cu-Cr-Al for HT-WGS.…”

Section: Resultsmentioning

confidence: 99%

Quaternary Fe‐Cu‐Cr‐Al HT‐WGS Catalysts – Effect of Al Substitution on the Efficiency at Steam‐Lean Process Gas

et al. 2020

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In the present work, we report on Fe–Cu–Cr–Al systems with various Cr/Al substitution as catalysts for high‐temperature water‐gas shift (HT‐WGS) to evaluate the possibility of Cr elimination and usability for carrying out the HT‐WGS process at steam‐lean process gas. The set of Fe–Cu–Cr–Al catalysts with the same Fe/Cu molar ratio and different Cr/Al molar ratio (0/∞) were prepared by the precursors' co‐precipitation and thermal treatment. The catalysts were investigated by XRF, DTG/MS, XRD, N2 sorption, H2‐TPR methods and activity tests. A relationship between Cr/Al ratio and physicochemical parameters and HT‐WGS activity, selectivity and stability of the catalysts have been estimated. Experimental results demonstrated that complete elimination of Cr from the Fe–Cu–Cr–Al catalyst is unfavorable, and it would lead to negative consequences as Cr enhances the catalyst activity and improve its durability.

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Studies on reduction of chromium doped iron oxide catalyst using hydrogen and various concentration of carbon monoxide

Cited by 25 publications

References 22 publications

Evolution of surface chemistry during sintering of water‐atomized iron and low‐alloyed steel powder

Evolution of surface chemistry during sintering of water‐atomized iron and low‐alloyed steel powder

Efficient Catalytic Combustion of Cyclohexane over PdAg/Fe₂O₃ Catalysts under Low-Temperature Conditions: Establishing the Degradation Mechanism Using PTR-TOF-MS and in Situ DRIFTS

Quaternary Fe‐Cu‐Cr‐Al HT‐WGS Catalysts – Effect of Al Substitution on the Efficiency at Steam‐Lean Process Gas

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Studies on reduction of chromium doped iron oxide catalyst using hydrogen and various concentration of carbon monoxide

Cited by 25 publications

References 22 publications

Evolution of surface chemistry during sintering of water‐atomized iron and low‐alloyed steel powder

Evolution of surface chemistry during sintering of water‐atomized iron and low‐alloyed steel powder

Efficient Catalytic Combustion of Cyclohexane over PdAg/Fe2O3 Catalysts under Low-Temperature Conditions: Establishing the Degradation Mechanism Using PTR-TOF-MS and in Situ DRIFTS

Quaternary Fe‐Cu‐Cr‐Al HT‐WGS Catalysts – Effect of Al Substitution on the Efficiency at Steam‐Lean Process Gas

Contact Info

Product

Resources

About

Efficient Catalytic Combustion of Cyclohexane over PdAg/Fe₂O₃ Catalysts under Low-Temperature Conditions: Establishing the Degradation Mechanism Using PTR-TOF-MS and in Situ DRIFTS