Oxygen Storage Capacity Research Articles

Sex-based variations in breath-holding: oxygen storage and diving response among non-divers

Breath-hold diving performances are typically better in men than in women. However, it is still being determined if there are differences in the physiological responses to breath-holding between the sexes. We conducted a study comparing the maximum breath-hold duration, heart rate (HR) reduction, peripheral oxygen saturation (SpO2), and spleen volume and contraction in 37 men and 44 women, all of whom had no prior breath-holding experience. They performed two dry apneas separated by 2 min; the first was limited to 60 s, followed by a maximal effort apnea. HR and SpO2 were measured continuously. Spleen diameters were measured via ultrasonography before and immediately following each apnea. The maximal apneic duration was longer in men (78 ± 19 s) compared with women (61 ± 18 s, p < 0.001), while the HR reduction was similar (women: 16% ± 19% versus men: 16% ± 17%, p = 0.973). The absolute splenic contraction was greater in men (59 ± 56 mL) compared with women (35 ± 28 mL, p < 0.001) in the first apnea, while the relative contraction was similar (women: 21% ± 17% versus men: 23% ± 13%, p = 0.528). In addition, the lowest SpO2 during the maximal apnea was similar between sexes (women: 93.3% ± 4.4%; men: 91.9% ± 4.3%, p = 0.161). We conclude that men have larger spleen size and contraction, lung size, and maximal apneic duration than women. The cardiovascular diving response is similar between sexes for those inexperienced with apneic diving. The longer breath-hold duration in men may be partly due to greater oxygen storage capacity, which results from larger vital capacity and greater spleen size and contraction.

Maximizing H2 Production from a Combination of Catalytic Partial Oxidation of CH4 and Water Gas Shift Reaction

A single-bed and dual-bed catalyst system was studied to maximize H2 production from the combination of partial oxidation of CH4 and water gas shift reaction. In addition, the different types of catalysts, including Ni, Cu, Ni-Re, and Cu-Re supported on gadolinium-doped ceria (GDC) were investigated under different operating conditions of temperature (400–650 °C). Over Ni-based catalysts, methane can easily dissociate on a Ni surface to give hydrogen and carbon species. Then, carbon species react with lattice oxygen of ceria-based material to form CO. The addition of Re to Ni/GDC enhances CH4 dissociation on the Ni surface and increases oxygen storage capacity in the catalyst, thus promoting carbon elimination. In addition, the results showed that a dual-bed catalyst system exhibited catalytic activity better than a single-bed catalyst system. The dual-bed catalyst system, by the combination of 1%Re4%Ni/GDC as a partial oxidation catalyst and 1%Re4%Cu/GDC as a water gas shift catalyst, provided the highest CH4 conversion and H2 yield. An addition of Re onto Ni/GDC and Cu/GDC caused an increase in catalytic performance because Re addition could improve the catalyst reducibility and increase metal surface area, as more of their surface active sites are exposed to reactants.

Accelerating the electrochemical performance of solid oxide fuel cells using a Ce(Gd, Bi, Yb)O2−δ diffusion barrier layer acting as an oxygen reservoir at high-current loading conditions

Ce(Gd, Bi, Yb)O2−δ with high oxygen storage capacity (OSC) facilitates stable oxygen supply to SOFCs under high current operation, leading to enhanced performance.

Effects of Rock Water with Different Alkalinity and Pre-Oxidation on Re-Ignition Characteristics of Residual Coal

ABSTRACT To investigate the impact of alkaline rock water (pH = 8, 9) combined with pre-oxidation on changes in pore structure and functional groups of residual coal in goaf, and consequently, on the secondary oxidation and spontaneous combustion characteristics of coal samples, an analysis was conducted. This analysis focused on examining changes in pore morphology and functional group content of pre-oxidized coal (OI0) and water-immersed oxidized coal (OI) through experiments utilizing low-temperature nitrogen adsorption and in-situ diffuse reflectance infrared spectroscopy. Secondary oxidation and spontaneous combustion characteristics of coal samples were analyzed using thermogravimetric differential thermal analysis incorporating oxidation kinetic theory. The findings indicated that after the combined effect of pre-oxidation and alkali leaching, the mesopore volume of the coal decreased, pore complexity increased, oxygen storage capacity was enhanced, and the apparent activation energy of the coal samples was significantly reduced. This reduction in activation energy was pronounced at lower temperatures but less so at higher temperatures. Specifically, the methyl and methylene contents of OI9 were significantly higher than those of other coal samples within the temperature range of 80–160°C. Meanwhile, the heat release of the low-temperature oxidation stages of OI0, OI8, and OI9 increased by 70.82%, 190.25%, and 75.05%, respectively, compared with RC. The study indicates an elevated risk of spontaneous coal combustion following the combined treatment of alkaline leaching and pre-oxidation. This research elucidates the mechanism of spontaneous combustion of water-immersed coal by alkaline rock water and pre-oxidation, providing valuable insights for the control of coal fires in alkaline mine-water environments.

Effect of La Addition to Ceria on the Oxygen Storage Capacity and the Energetics of Water Adsorption

Effect of La Addition to Ceria on the Oxygen Storage Capacity and the Energetics of Water Adsorption

Enthalpy increments and redox energetics of titanium-substituted strontium ferrites SrTi1-xFexO3-δ

For three perovskites from the Sr(Ti,Fe)O3-δ (STF) system—SrTi0.7Fe0.3O3-δ (STF30), SrTi0.5Fe0.5O3-δ (STF50), and SrTi0.3Fe0.7O3-δ (STF70)—the enthalpy of oxidation, ΔHox, measured by Calvet calorimetry, was found to be an almost temperature-independent function of δ. The data on ΔHox(δ) allowed subtracting the redox contribution from the drop calorimetric measurement results, yielding the enthalpy increments of STF with fixed oxygen content. The heat capacities of these STF oxides were successfully described by the single Einstein term, with the fitted Einstein temperatures depending almost linearly on titanium content. The additional dilatometric and thermogravimetric measurements were used to estimate the thermal (TEC) and chemical expansion coefficients of STF. While TEC somewhat decreases with titanium content, the chemical expansion remains rather high for all STF. Finally, the obtained thermochemical data were used to compare the energy and oxygen storage capacities of different STF with those of undoped strontium ferrite; both were found to decrease noticeably with titanium substitution. Hence, in applications such as chemical looping, e.g., in solar energy conversion and storage, the STF with lower titanium content would possess better functional properties, although they might be less chemically stable than titanium-rich STF oxides.

Highly stable Co/CeO2 catalyst for high-temperature water–gas shift reaction using a CeO2 support with an optimized precipitant ratio

We report hydrogen production from waste through waste gasification and the water–gas shift reaction using highly stable Co/CeO2 catalysts. Here, careful control of the KOH:K2CO3 precipitant ratio during CeO2 support synthesis yielded highly active and stable Co/CeO2 catalysts. Crucially, the precipitant ratio affects the Co dispersion, oxygen vacancies, crystallinity, and Co-CeO2 interactions, and the Co dispersion increases with increase in KOH content. Further, the oxygen storage capacity improves at the optimal KOH:K2CO3 ratio. In addition, the Co-CeO2 interaction is enhanced when catalysts are synthesized using CeO2 with a large amount of K2CO3. All prepared Co/CeO2 catalysts show high CO conversion, even at extremely high gas hourly space velocities: the Co/CeO2 (λ = 2:1 and 1:1.5) catalysts exhibit stable performance because of robust Co-CeO2 interactions, high oxygen storage capacities, and effective Co dispersions. These findings aid hydrogen production from waste and CeO2 support design for various catalytic reactions.

Low-Temperature Cation Ordering in Ce0.5-XZr0.5+XO2 Under Precisely Controlled P(O2)

CeO2-ZrO2 solid solutions (CZ) with a high oxygen storage capacity (OSC), owing to the valence change of Ce ions upon reduction, have been utilized to control the P(O2) of automobile exhaust purification systems. In the CeO2-ZrO2 system, cation-ordered κ-Ce2Zr2O8 shows the highest OSC; however, cation ordering requires high-temperature heat treatment, typically higher than 1200 °C, under a reducing atmosphere [1], which leads to grain growth and a decrease in OSC. Our previous study revealed that the addition of a small amount of Fe2O3 reduces the cation-ordering temperature to 800 °C, although the mechanism is unknown [2]. In this study, in-situ high-temperature XRD revealed that Fe2O3 plays an important role in cation ordering by precisely controlling P(O2), which assists the nucleation of the ordered phase. Furthermore, the effect of the Ce/Zr ratio on the ordering behavior was investigated because Zr-rich CZ (Ce0.5-xZr0.5+xO2) with a high proportion of Zr is expected to suppress grain growth, thereby improving the specific surface area and OSC. Thus, this study discusses the mechanism of low-temperature cation ordering of Zr-rich CZ solid solutions by Fe2O3 addition and evaluates their OSC. DFT-based first-principles calculations revealed that Zr-rich Ce0.375Zr0.625O2 was less likely to be ordered than Ce0.5Zr0.5O2 (Ce/Zr=1) because the energy gain resulting from cation ordering was smaller by 0.35 eV/f.u. Meanwhile, in the disordered phases, the oxygen vacancy formation energy was negatively larger by 0.12 eV/f.u. in the Zr-rich CZ than in Ce0.5Zr0.5O2, suggesting that the Zr-rich CZ was more readily reduced. The in-situ high-temperature XRD revealed that Fe2O3-added Zr-rich Ce0.5-xZr0.5+xO2 (0.05 < x < 0.1) was not ordered under dry 10%H2-N2; however, surprisingly, it was successfully ordered under wet 4.5%H2-N2, which provides a weak reducing atmosphere. It should also be noted that Zr-rich CZ without Fe2O3 addition was not ordered, regardless of the gas composition. In addition, the Zr-rich CZ embedded in the mixture of Fe2O3 and Fe3O4 powders and heat-treated at 900 °C showed significant grain growth, which seems to be related to the initial stage of cation ordering. Based on these results, a moderately reducing atmosphere rather than a highly reducing one leads to a deeper reduction of the Zr-rich CZ, which triggers cation ordering. A more detailed thermodynamic discussion is also provided. The cation-ordered Zr-rich κ-Ce1.79Zr2.21O8 showed an excellent OSC of 688 μmol-O2/g at 400 °C excluding the reduction amount of Fe2O3 added, which is 96±6 % of the theoretical OSC, even without precious metal group catalysts.

Cerium-induced modification of acid-base sites in Ni-zeolite catalysts for improved dry reforming of methane

Dry reforming of methane (DRM) is a promising route to mitigate greenhouse gas emissions by converting CH4 and CO2 into valuable syngas. The present work explores the effect of Ce addition to Ni-based catalysts supported on CBV3020E (ZSM-5) for DRM. The use of Ce as a promoter to tune the acid-base properties of zeolites for DRM is addressed for the first time in detail. While Ce has traditionally been used to improve oxygen storage capacity, this work explores its novel use as a means to enhance surface basicity and promote CO2 adsorption. The samples were prepared by wet impregnation, characterized using N2-sorption, X-ray diffraction, H2-temperature-programmed reduction, temperature-programmed desorption of CO2 and ammonia, and Fourier transforms infrared spectroscopy, and tested for DRM at 800 °C and 42,000 mL/g.h GHSV. Results show that ZSM-5 zeolite can be beneficial in achieving high metal dispersion. The introduction of 2 wt% Ce to Ni5/ZSM-5 increases the concentration of strong basic sites, resulting in improved catalytic performance from 37 % CH4 conversion and 48 % CO2 conversion for Ni5/ZSM-5 to 55 % and 65 % on promoted Ni5Ce2/ZSM-5, respectively. Thus, the best results are observed on Ni5Ce2/ZSM-5 and an optimal H2/CO ratio of 0.84 is achieved in this case. Upon decreasing GHSV to 15,000 mL/g.h, CH4 and CO2 conversions jump to 83 % and 88 %, respectively on Ni5Ce2/ZSM-5. Cerium doping produces more desirable strong basic sites and enhances NiO reducibility. This promotes CO2 adsorption and drives the catalytic reaction towards syngas formation, which eventually results in increased efficiency and improved performance.

Deciphering the Ce3+to Ce4+Evolution: Insight from X-ray Raman Scattering Spectroscopy at Ce N4,5Edges.

Cerium oxide, or ceria, (CeO2) is one of the most studied materials for its wide range of applications in heterogeneous catalysis and energy conversion technologies. The key feature of ceria is the remarkable oxygen storage capacity linked to the switch between Ce4+ and Ce3+ states, in turn creating oxygen vacancies. Changes in the electronic structure occur with oxygen removal from the lattice. Accordingly, the two valence electrons can be accommodated by the reduction of support cations where the electrons can be localized in empty f states of Ce4+ ions nearby.Quantifying the different oxidation states in situ is crucial to understand and model the reaction mechanism. Beside the different techniques to quantify Ce3+ and Ce4+ states, we discuss the use of X-ray Raman Scattering (XRS) spectroscopy as an alternative method. In particular, we show that XRS can observe the oxidation state changes of cerium directly in the bulk of the materials under realistic environmental conditions. The Hilbert++ code is used to simulate the XRS spectra and quantify accurately the Ce3+ and Ce4+ content. These results are compared to those obtained from in situ X-ray Diffraction (XRD) collected in parallel and the differences arising from the two different probes are discussed.

Boosting oxygen storage capacity of Fe-Cu bimetallic catalysts through sulfide modification for efficient and selective molecular oxygen activation

Molecular oxygen (O2), a reactive oxygen species precursor, has great potential for water purification, but its spin-forbidden resistance hinders its direct involvement in the redox reactions of organic compounds under mild ambient conditions. In this study, a facile strategy was employed to synthesize sulfide-modified Fe-Cu bimetallic catalysts (FeCu-S) to enhance the activation efficiency of O2. The results showed that the FeCu-S material exhibited a tenfold increase in O2 activation compared to that of the control group, primarily attributed to the increased specific surface area of the catalysts with an optimized Fe/Cu site distribution and promoted generation of Cu-containing crystalline phases (e. g., CuFeS2 and CuO) to significantly enhanced the oxygen storage capacity. Moreover, such Cu-containing crystalline phases strengthened surface electron transfer, thus remarkably promoting the selective generation of singlet oxygen (1O2) for sulfamethoxazole (SMX) degradation. The FeCu-S/O2 system maintained high activity after the fifth recycle with stable reaction pH and negligible leaching of Cu and Fe ions, also exhibited great performance in the advanced treatment of the real biological effluent and ultrafiltration effluent from landfill leachate, confirming its great potential for practical water purification applications.

Diving into the influence of phosphorus on ceria-supported copper manganese bimetallic oxides for catalytic removal of carbon monoxide

The application of ceria-supported catalysts as promising catalysts for air pollutant abatement via heterogeneous catalytic processes is still a challenge. Phosphorus (P) is a potential threat to catalyst deactivation but has not been sufficiently explored. Herein, a systematic study reveals the poisoning behaviors of P on Cu-Mn bimetallic oxides supported by ceria (Cu-Mn/CeO2) as a typical case in CO oxidation and provides new insights into the deactivation mechanism. The P impregnation decreases the surface area of Cu-Mn/CeO2 and leads to the emergence of a new sheet morphology. The interactions between P and catalyst components (support and active species) result in the generation of dominant P species of PO43− and PO3−. The P addition also weakens the oxygen storage capacity of ceria and decreases the proportions of low-valent Cu and Mn, hindering electron transfers among metals. Furthermore, the reducibility and the adsorption and activation of O2 are limited in P-loaded Cu-Mn/CeO2 catalysts as found in H2-TPR and O2-TPD when increasing the P concentration. In situ DRIFTS experiments demonstrate that the inhibition of the formation and transformation of active intermediates, namely carbonyls and carbonates, is responsible for the poisoning behaviors of P in the pathway of CO oxidation over Cu-Mn/CeO2 catalyst.

Strain Effects on the Adsorption of Water on Cerium Dioxide Surfaces and Nanoparticles: A Modeling Outlook.

Nanocrystalline ceria exhibits significant redox activity and oxygen storage capacity. Any factor affecting its morphology can tune such activities. Strain is a promising method for controlling particle morphology, whether as core@shell structures, supported nanoparticles, or nanograins in nanocrystalline ceria. A key challenge is to define routes of controlling strain to enhance the expression of more active morphologies and to maintain their shape during the lifespan of the particle. Here, we demonstrate a computational route to gain insights into the strain effects on particle morphology. We use density functional theory to predict surface composition and particle morphology of strained ceria surfaces, as a function of environmental conditions of temperature and partial pressure of water. We find that adsorbed molecular water is not sufficient to shift stability and as such under all compressive and tensile strains studied, the most stable particle is of octahedral shape, similarly to the unstrained case. When dissociative water is involved at the surfaces of the particle, then the most stable particle morphology changes under high water coverage and tensile strain to cuboidal or truncated cuboidal shapes. This shift in shape is due to strain effects that affect the strength of water adsorption.

Deciphering the structural origin for the remarkable CO oxidation activities of the CuO-based catalysts with diverse morphological CeO2 supports

In this work, octahedral, cubic, particle-like, spherical and rod-shaped nano-CeO2 supports were synthesized by hydrothermal method. CuO/CeO2 catalysts were then prepared via an ultrasonic-assisted impregnation method, employing these differently shaped CeO2 supports. The resulting catalysts were tested for their performance in CO oxidation. The findings revealed that the CuO active sites significantly influenced the oxygen storage and release capacity of CeO2, thereby improving its catalytic activity for low-temperature CO oxidation. The key factors affecting the CO oxidation performance of CuO/CeO2 catalysts with different CeO2 morphologies were investigated through various characterizations. It was found that the specific surface area was not the primary factor in determining catalytic activity. Instead, the exposed crystal planes played a crucial role. By adjusting the crystal plane exposure of CeO2, the supported 1CuO/CeO2 catalysts exhibited different crystal surface configurations. Notably, the 1CuO/CeO2-S catalyst, with exposed (100) and (110) crystal planes, and the 1CuO/CeO2-P catalyst, with exposed (111), (100), and (110) planes, exhibited higher surface defect concentrations. This increased defect concentration facilitated the formation of Cu+ species, enhancing the redox properties and further improving the overall catalytic performance of CO oxidation.

The impact of support selection and Co loading amount on the catalytic performance for methane combustion

Methane (CH4) is a key component of natural gas and is essential for energy production and utilization. However, due to its strong greenhouse effect, efficient catalytic combustion methods are needed to convert it into CO2 and H2O. This study systematically evaluates the catalytic performance of Co, CoO, and Co3O4 in methane catalytic combustion, particularly highlighting the superior activity of Co3O4. To improve catalytic efficiency, this paper examines the effects of SiO2, Al2O3, and CeO2 as support materials using co-precipitation and impregnation methods. The results show a significant improvement in the catalytic activity of Co3O4 supported on CeO2, attributed to CeO2's unique redox properties and high oxygen storage capacity. Additionally, the study explores the impact of different loading amounts (5%, 10%, 15%, 20%) of Co3O4(x)-CeO2 catalysts on their performance. The optimal 10%wt Co3O4–CeO2 catalyst achieves methane conversion rates of 10%, 50%, and 90% at temperatures of 376 °C, 473 °C, and 578 °C, respectively, demonstrating exceptional stability during a 20-h stability test and the ability to adapt to fluctuations in CH4 concentrations in low-oxygen environments, while also exhibiting significant catalytic activity across a range of methane concentrations from 0.5% to 2.5%. These findings provide important theoretical and experimental guidance for the application of cobalt-based catalysts in CH4 combustion, paving the way for future catalyst design and optimization.

Nickel doped enhanced LaFeO3 catalytic cracking of tar for hydrogen production

The transformation of biomass into green energy was pivotal for sustainable development, yet the efficient conversion of biomass-derived tar into hydrogen-rich syngas remained a significant challenge. This study addressed the catalytic demand for hydrogen production from tar, focusing on the development of LaNixFe1-xO3 perovskites as catalysts. A series of LaNixFe1-xO3 perovskites with varying nickel doping levels (x=0, 0.25, 0.5, 0.75, 1) were synthesized to evaluate their catalytic performance in converting toluene, a representative tar component, into hydrogen. The LaNi0.5Fe0.5O3 catalyst demonstrated the highest hydrogen yield (14.5 L/6 h) and volume percentage (82.9 V/V%), highlighting the optimal nickel doping level for enhancing hydrogen production. The hydrogen production performance of LaNixFe1-xO3 was significantly affected by nickel doping. In particular, a small amount of nickel doping can significantly enhance the hydrogen production capacity of LaFeO3 and maintain good reaction stability. The enhanced performance was attributed to the high oxygen storage capacity of perovskite, which facilitated the removal of surface carbon and promotes the methanation reaction. Notably, the total content of defect oxygen and surface adsorbed oxygen/hydroxyl groups significantly impacted the hydrogen production efficiency. These findings indicated that LaNi0.5Fe0.5O3 was an effective catalyst for converting biomass-derived tar into hydrogen-rich syngas, offering a promising solution to the catalytic demand in the hydrogen production system.

A detailed characterization study of Ni/CeO2 catalysts identifies Ni availability as the primary factor affecting CO2 methanation performance

The structure of a catalyst has a strong impact on its performance. Here we investigate the physicochemical properties of Ni/CeO2 in an attempt to draw structure–activity relationships for CO2 methanation. A combination of characterisation methods (X-ray diffraction (XRD), 4D Scanning Transmission Electron Microscopy (4D-STEM), CO chemisorption and oxygen storage capacity study etc.) clearly demonstrates the effect of Ni crystallite size, Ni availability (i.e. catalytically accessible Ni) and oxygen vacancies at the Ni-CeO2 interface in Ni/CeO2 during CO2 methanation. Among them, the role of exposed Ni active sites is highlighted, and two possible optimisation schemes i.e. changing the support calcination temperature and the final calcination atmosphere are proposed to obtain a better dispersal of Ni NPs (nanoparticles) on CeO2. Both modification methods do not affect the reaction route, and the activity differences of Ni/CeO2 can be explained by the various hydrogenation rate of formate species, as confirmed by in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS) measurements.

Enhancing Ce-Co interfacial effects via special petal-pollen morphology construction to achieve efficient toluene removal

Interfacial effects provide an effective means to construct multi-metal interactions and design efficient catalysts for VOCs purification, while morphology construction remains a common tactic to optimize the efficiency of these catalysts. In the present work, the Co-Ce bimetal interface was effectively constructed by morphological regulation, and the coupling of the interfacial effect modulation and the special morphological structure was realized, resulting in superior catalyst performance. Among the series catalysts, CeCoOx-H demonstrated the optimized activity with 90 % toluene conversion at 250 °C while maintaining good results in a 50 h stability test. And the systematic characterization revealed that the structural changes and interfacial effects induced by morphological modulation would increase the structural defects, improving surface reactive oxygen and oxygen vacancy content, oxygen storage capacity, oxygen motivity and low-temperature reductivity, which account for promising catalytic performance of CeCoOx-H. Furthermore, in-situ DRIFTS revealed the following decomposition routes for toluene on the CeCoOx-H catalyst surface: toluene → benzyl alcohol → benzaldehyde → benzoate → phenol → maleate → acetate → formate → carbon dioxide. In particular, the decomposition of benzaldehyde and benzoate may be the key steps in toluene catalytic oxidation. Also, the characterization unveiled that the rich adsorption sites brought by the interfacial construction are not negligible in boosting the catalytic performance.

Influence of electrodes on the resistive switching characteristics of Al/Gd2Zr2O7/E (E=Al or ITO) RRAM devices

Sol-gel derived amorphous Gd2Zr2O7 (GZO) thin films with Al/GZO/E (E = ITO or Al) structures were prepared to demonstrate the effect of electrode material on the switching behavior of resistive random access memory (RRAM) devices. All devices exhibit bipolar resistive switching (BRS) mode. After the post-metal annealing (PMA) treatment, the AlOx interfacial layer contributes to enhancing oxygen ion storage capacity and limiting the electromigration of aluminum metal. The forming-free Al/GZO/ITO device exhibits a switching cycle of 3027, a Vset/Vreset ratio of −1.83 V/0.56 V, a Ron/Roff ratio of approximately 10, and a retention time of 104 s. And the Al/GZO/Al device features a dual-layer AlOx structure, significantly improving the integrity of filament rupture to reduce leakage current and increase the switching window. Its switching cycle is 1946, with a Vset/Vreset ratio of −3.47 V/0.29 V, a Ron/Roff ratio of approximately 102, and a retention time of 104 s. The oxygen storage capacity of the dual-layer AlOx interfacial layer in the Al/GZO/Al device surpasses that of the Al/GZO/ITO device, allowing for a reduction in the reset voltage and ensuring more complete filament rupture, thereby enhancing the RHRS. Accordingly, GZO thin films can be applied to achieve the desired RS characteristics on different electrodes, making them promising candidates for RRAM applications.

Enhanced Low‐Temperature Oxidation Activity of Cu‐Doped Highly Active Pd‐Based Catalysts

AbstractPd‐based catalysts supported on cerium–zirconium (CZ) oxygen storage materials (OSM) have emerged as promising candidates for the catalytic oxidation of CH4 and CO. However, achieving efficient and stable treatment of CH4 and CO in exhaust gases with Pd‐based catalysts remains a long‐term challenge. To address this, we propose a straightforward strategy of doping the supports with Cu to enhance the catalytic performance of Pd/Ce0.4Zr0.5La0.1O1.95 catalysts. Performance tests revealed that the catalytic activity of the Cu‐doped catalysts significantly improved, with T90 (CH4) decreasing from 418–301 °C and T90 (CO) decreasing from 141–113 °C. Notably, the copper‐doped catalysts exhibited enhanced water and sulfur resistance while maintaining excellent thermal stability. The CO conversion decreased by less than 2 % after a thermal deactivation experiment lasting over 100 hours. The reduction in particle size and the increase in specific surface area due to copper doping are key factors contributing to the improved total oxygen storage capacity (OSC). The main reasons for the increase in total OSC are likely the reduced particle size and increased specific surface area.