Doped Ceria Research Articles

Influence of cerium doping on the magnetic properties of a nanometric cobalt-zinc mixed ferrite

This study investigates the influence of cerium doping on the magnetic properties of nanometric-sized particles of a cobalt-zinc mixed ferrite with stoichiometric formula Co0.6Zn0.4Fe2O4. The effect of cerium doping was studied by producing a ferrite with the stoichiometric formula Co0.6Zn0.4Fe1.95Ce0.05O4 and comparing its magnetic properties with those of undoped cobalt-zinc ferrite and other ferrites. The samples were synthesized by sol-gel combustion and characterized by X-ray diffraction (XRD), vibrating-sample magnetometry (VSM) and ferromagnetic resonance (FMR). The XRD results confirm the synthesis of ferrite, the VSM results show that the saturation magnetization decreases with cerium doping and the FMR results show that the magnetocrystalline anisotropy decreases with cerium doping. Comparison with other ferrites suggests that doping with 5% cerium does not significantly decrease the microwave absorption of cobalt-zinc ferrite while protecting healthy cells in hyperthermy.

Cerium doping of 45S5 bioactive glass improves redox potential and cellular bioactivity

45S5 Bioglass (BG) is composed of a glass network with silicate based on the component and can be doped with various therapeutic ions for the enhancement of hard tissue therapy. Nanoceria (CeO2) has been shown to indicate redox reaction and enhance the biological response. However, few studies focus on the proportion of CeO2-doped and its effect on the cellular bioactivity of CeO2-doped BG (CBG). In this study, we synthesized the CBG series with increasing amounts of doping CeO2 ranging (1 to 12) wt.%. The synthesized CBG series examined the characterization, mineralization capacity, and cellular activity against BG. Our results showed that the CBG series exhibited a glass structure and indicated the redox states between Ce3+ and Ce4+, thus they showed the antioxidant activity by characterization of Ce. The CBG series had a stable glass network structure similar to BG, which showed the preservation of bioactivity by exhibiting mineralization on the surface. In terms of biological response, although the CBG series showed the proliferative activity of pre-osteoblastic cells similar to BG, the CBG series augmented not only the alkaline phosphatase activity but also the osteogenic marker in the mRNA level. As stimulated the osteogenic activity, the CBG series improved the biomineralization. In conclusion, the CBG series might have a potential application for hard tissue therapeutic purposes.

Enhanced Hydrogen Production in Microwave‐Driven Water‐Splitting Redox Cycles by Engineering Ceria Properties

AbstractSustainable hydrogen, produced from renewable sources such as solar or wind, plays a decisive role in driving industrial decarbonization. Among hydrogen production technologies, steam electrolysis, and solar‐driven thermochemical cycles using reducible solid oxides show promise but face challenges due to high operation temperatures. Microwave‐driven redox chemical looping enables the direct, contactless electrification of the process, reducing the operation temperature and complexity. Previous works showed that microwaves can efficiently drive reduction/water‐splitting cycles using Gd‐doped ceria at low temperatures (<250 °C), but adjustment of material properties is needed. Here, the key properties of materials are explored that affect the redox mechanism by screening a series of doped ceria materials to enhance microwave‐driven hydrogen production. Evaluation of trivalent dopants (La3+, Gd3+, Y3+, Yb3+, Er3+, and Nd3+) reveals that reduction correlates with lattice and electronic properties. The composition Ce0.9La0.1O2‐δ achieves 1.41 mL g−1, the highest hydrogen production among the studied series. Its narrower bandgap allows for reaching higher conductivity upon microwave‐driven reduction at lower temperatures, while a larger ionic lattice size boosts solid‐state oxygen diffusion. Overall, this research remarks on the critical properties of ceria‐based materials that enhance hydrogen production in microwave‐driven water‐splitting cycles, supporting the design of more efficient materials for sustainable chemical production technology.

Stabilization of phase‐pure tetragonal zirconia ceramics with minimum CeO2 doping and associated benefits

AbstractIn the quest of finding the minimum ceria doping for a stabilized zirconia matrix, we report a remarkable structure–property correlation for a high (> 99%) density, fine grained (∼100 nm), fully phase‐pure (confirmed via both slow scan X‐ray diffraction and Raman spectroscopy) tetragonal 10 mol.% CeO2‐doped zirconia ceramics (10Ce‐TZP). A starting near spherical, ultrafine (∼7 nm) powders with high surface area (∼170 m2/g) ensured the conventional pressureless sintering at 1150°C without the need of any additives, binders, and/or sintering aid to achieve this high density. No monoclinic phase was traced at the end of the low‐temperature degradation test for 100 h in boiling water; negligible (∼5% monoclinic phase) amounts showed up in the thermal quenching tests. The sintered 10Ce‐TZP ceramic recorded comparable/better hardness and indentation toughness value with respect to higher (i.e., 12 mol.%) ceria doped‐zirconia systems. For the first time, nanograined translucent 10Ce‐TZP ceramic portrayed a remarkable transmittance of ∼38% at 600 nm wavelength for 0.6 mm thick pellet.

Tuning metastable austenite in a phase-transforming ceramic via matrix constraint

Martensitic phase-transforming ceramics can undergo reversible phase transformations under thermo-mechanical stimuli, yet brittle in their monolithic, polycrystalline form. Incorporating these ceramics into matrices thereby metastabilizing austenite gives rise to a significant toughening effect by triggering martensitic transformation. However, it remains a challenge to stabilize the austenite if the matrix is a light metal, because of its low strength, low melting temperature and high-chemical reactivity. In this study, we constructed a phase-transforming ceramic-metal (zirconia-aluminum) composite with tunable metastable austenite fractions via matrix constraint. Systematic experiments combined with thermodynamic and kinetic models uncover the effect of the matrix constraint and doping concentration on austenitization. By varying the processing parameters, we realized extensive tunability in metastable austenite content (0–100 wt.%) under different cerium doping concentrations (6–12 mol.%) in a wide range of processing temperatures (350–550°C). Our findings reveal the underlying mechanisms for promoting, stabilizing and fine-manipulating austenitization in martensitic phase-transforming ceramics under geometrical constraint, and may lay out the foundation for more extensive studies and applications of these phase-transforming ceramic-based composites.

Ce-Doped SnO2 Electron Transport Layer for Minimizing Open Circuit Voltage Loss in Lead Perovskite Solar Cells.

In the planar heterostructure of perovskite-based solar cells (PSCs), tin oxide (SnO2) is a material that is often used as the electron transport layer (ETL). SnO2 ETL exhibits favorable optical and electrical properties in the PSC structures. Nevertheless, the open circuit voltage (VOC) depletion occurs in PSCs due to the defects arising from the high oxygen vacancy on the SnO2 surface and the deeper conduction band (CB) energy level of SnO2. In this research, a cerium (Ce) dopant was introduced in SnO2 (Ce-SnO2) to suppress the VOC loss of the PSCs. The CB minimum of SnO2 was shifted closer to that of the perovskite after the Ce doping. Besides, the Ce doping effectively passivated the surface defects on SnO2 as well as improved the electron transport velocity by the Ce-SnO2. These results enabled the power conversion efficiency (PCE) to increase from 21.1% (SnO2) to 23.0% (Ce-SnO2) of the PSCs (0.09 cm2 active area) with around 100 mV of improved VOC and reduced hysteresis. Also, the Ce-SnO2 ETL-based large area (1.0 cm2) PSCs delivered the highest PCE of 22.9%. Furthermore, a VOC of 1.19 V with a PCE of 23.3% was demonstrated by Ce-SnO2 ETL-based PSCs (0.09 cm2 active area) that were treated with 2-phenethylamine hydroiodide on the perovskite top surface. Notably, the unencapsulated Ce-SnO2 ETL-based PSC was able to maintain above 90% of its initial PCE for around 2000 h which was stored under room temperature condition (23-25 °C) with a relative humidity of 40-50%.

Bimetallic cobalt-cerium oxides activated fenton-like process for organic contaminant removal: Role of high-valent cobalt species modulated by oxygen vacancies

Cobalt-cerium bimetallic oxides (CoCeOx) with rich oxygen vacancies (OVs) were prepared by solvothermal method for peroxymonosulfate (PMS) activation efficiently, and the effect of OVs on reactive species formation was discussed. Carbamazepine (CBZ), a widely used anti-epileptic drug, also a typical pharmaceutical and personal care products (PPCPs) in the water environment, could be removed by 98 % in 40 min with low addition of CoCeOx and PMS in the CoCeOx/PMS system. Through a series of quenching experiments and electron paramagnetic resonance, it was confirmed that the main reactive species for decontamination were high-valent cobalt oxygen species (Co(IV)). Through the OVs detection and the contribution calculation of radicals and non-radicals on CBZ removal, it was found that OVs promoted the transformation from radicals to non-radicals (mainly Co(IV)) in the systems. In addition, cerium doping played an important role in promoting Co (II) / Co (III) cycle and OVs regeneration. Density functional theory (DFT) calculation revealed the formation process of Co(IV), and further proved that OVs could promote the formation of Co(IV). Evaluated by quantitative structure–activity relationship (QSAR) analysis, the ecotoxicity of CBZ and its main intermediates was significantly decreased. Overall, this study deepens the understanding of OVs promoting the formation of high-valent metal oxygen species (HVMO), as well as provides feasibility for the removal of refractory organics in wastewater.

Lanthanum and cerium functionalised forestry waste biochar for phosphate removal: Mechanisms and real-world applications

Phosphorus as a diminishing finite resource, yet is an essential element for the growth of biota. However, elevated concentrations in water can imbalance ecosystems and cause eutrophication. To address both problems, two highly efficient biochars, namely La-OB and CeLa-OB were synthesised by lanthanum and cerium doping. The performance of La-OB and CeLa-OB were evaluated in both batch and dynamic regimes with synthetic phosphate (PO43--P) solutions and eutrophic lake water. PO43--P adsorption mechanisms were investigated in terms of pH, kinetics, isotherms, activation energy, thermodynamics and using in-depth characterisation (XPS, FTIR, XRD, BET, pHpzc and SEM-EDX). The feasibility of using such biochar in ‘real life’ situations was studied with column filtration of lake water with low and high PO43--P concentrations. Reusability/desorption and toxicity in the water environment was also considered. The mechanistic study showed that both biochars predominantly had inner-sphere complexes with La and Ce ligands (as a monolayer), while outer-sphere complexation was less common. The exothermic adsorption process followed the Elovich kinetic and Langmuir isotherm models, with a maximum adsorption capacity of 112 mg/g for La-OB and 40 mg/g for CeLa-OB. In column filtration trials the adsorption capacity reached 78 mg/g, while low metal leaching (0.08 mg/L) and low toxicity to Lepidium sativum germination were detected. The results indicated that these biochars, especially La-OB, could be used in circular economy-based water treatment.

Effect of the interaction of Fe- and Ce-contents on the structure and magnetic properties of M-type strontium ferrites

Sr1-xCexFe12O19 and Sr1-xCexFe12-yO19-δ (x = 0–0.2, y = 0–2) powders were synthesized by sol-gel auto-combustion method, and the effect on the structure and magnetic properties of changes in doping concentration and iron content has been investigated. XRD results confirmed the formation of M phase and impurities of CeO2 and Fe2O3. The SEM results show that cerium doping leads to a decrease in grain size. For Sr1-xCexFe12O19, the saturation magnetization increases to 77.73 emu/g first and then decreases with the increase of cerium doping. More importantly, our study also found that as the Ce doping concentration and iron content change, the interaction between the two changes differently. This interaction will have different effects on the occupancy of iron ions at spin-up and spin-down sites, ultimately leading to a significant characteristic change in magnetic properties. For Sr1-xCexFe12-yO19-δ, with the iron content decreases, the magnetic properties continue to decrease at x = 0.03, increase first and then decrease at x = 0.1, and keep improving at x = 0.2. It is of reference significance to change the magnetic properties of strontium ferrites by adjusting the relationship between rare earth doping concentration and iron content.

Probing the structure of divalent impurity cations doped ceria nanocubes for photocatalytic activity

Ceria has attracted a lot of interest in scientific community due to its several technological uses. During this study, composite hydroxide-mediated method was used to prepare nanocubes of undoped and doped ceria. The prepared materials were characterized using a number of analytical techniques including room temperature powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) theory, and UV–Visible spectroscopy to investigate the structural, morphological, optical and photocatalytic properties. No impurity phases were observed from the XRD revealing face centred cubic (FCC) crystal symmetry of the undoped and doped ceria. The formation of nanocubes was confirmed by SEM. Pore sizes in the range of 24.9–29 mm were revealed by BET analysis. A gradual increase in photodegradation efficiency with an increase in irradiation time was seen for the doped samples compared to undoped ceria, showing suitability for photocatalytic applications. An increase in defect concentrations especially for Sr2+ doped samples indicated by the quantitative analysis of Raman spectra reveals potential for electrolytic applications in fuel cells provided necessary conductivity and long-term performance testing would need to be done.

Electrocatalysts with Highly Dispersed Cerium in Nickel Matrix for Hydrogen Evolution in Alkaline Electrolyte

AbstractIt is challenging to develop highly active and durable electrocatalysts for hydrogen evolution reaction (HER) in alkaline water electrolysis. Herein, an electrocatalyst is synthesized with highly dispersed cerium in a nickel matrix, showing an overpotential of 169 mV for HER at a current density of 500 mA cm−2, about 137 mV lower than that observed without cerium. Kinetic analysis results suggest that doping cerium facilitates the evolution of intermediate H for HER, thus accelerating the process of water dissociation. Density functional theory (DFT) calculations also indicate that the introduction of highly dispersed cerium can lower the energy barrier of the kinetically sluggish Volmer step by altering the orbital occupation near the Fermi level, promoting the process of water dissociation. Furthermore, the electrolyzer constructed with the electrocatalyst exhibits a cell voltage as low as 1.67 V at 800 mA cm−2 for 2000 h in 7 м KOH at 80 °C. The robust property makes it an excellent candidate electrocatalyst for practical applications.

Enhanced Hydrogen-Storage Properties of MgH2 Catalyzed via a Cerium Doped TiCrV BCC Alloy

In this work, Ce-doped Ti6Cr14V80 BCC hydrogen-storage alloys have been synthesized as catalysts to enhance the hydrogen-storage performance of MgH2 based on its room-temperature activation features and excellent durability. The Ti6Cr14V80Ce1 alloy was pre-ball milled under a hydrogen atmosphere into a Ti6Cr14V80Ce1Hx hydride. Different amounts of the Ti6Cr14V80Ce1Hx hydride were incorporated into MgH2 by ball milling to obtain the MgH2 + y wt%Ti6Cr14V80Ce1Hx (y = 0, 3, 5, 10, 15) nano-composites. With an optimization doping of 10 wt%Ti6Cr14V80Ce1Hx, the initial dehydrogenated temperature was decreased to 160 °C. Moreover, the composite can rapidly release 6.73 wt% H2 within 8 min at 230 °C. Also, it can absorb 2.0 wt% H2 within 1 h even at room temperature and uptake 4.86 wt% H2 within 10 s at 125 °C. In addition, the apparent dehydrogenated activation energy of the MgH2 + 10 wt%Ti6Cr14V80Ce1Hx composite was calculated to be 62.62 kJ mol−1 fitted by the JMAK model. The capacity retention was kept as 84% after 100 cycles at 300 °C. The ball milled Ti6Cr14V80Ce1Hx transformed from the initial FCC phase structure into a BCC phase after complete dehydrogenation and back into an FCC phase when fullly hydrogenated. A catalyst mechanism analysis revealed that the ‘autocatalytic effect’ originating in Ti6Cr14V80Ce1Hx plays a crucial role in boosting the de-/hydrogenation properties of MgH2. This work provides meaningful insights into rational designs of nano-compositing with different hydrogen-storage alloy catalyzed MgH2.

Cerium doping modulates the surface electronic structure of IrOx/TiN to promote the stability of acid oxygen evolution

The stability of supported Ir-based catalysts in acid oxygen evolution reaction (OER) remains a pressing challenge, which hinders the commercial viability of proton exchange membrane water electrolysis (PEMWE) technology. Herein, we propose a cerium doping strategy to enhance the stability of supported Ir-based catalyst toward OER. The Ce-doped supported catalysts, designated as Ce-IrOx/TiN, were synthesized using an organic colloidal method. Transmission Electron Microscopy (TEM) analysis reveals highly dispersed IrOx nanoparticles averaging 1.5 nm on the TiN support. X-ray Photoelectron Spectroscopy (XPS) investigations further elucidate that Ce doping effectively stabilizes the Ir species predominantly in states below 4+, crucial for modulating the surface electronic structure and thereby improving both the activity and stability of the catalysts. Electrochemical characterization highlights the superior performance of the optimized catalyst, 6 %-Ce-IrOx/TiN, with an impressively low overpotential of 242 mV at 10 mA cm−2 and a Tafel slope of 57.5 mV dec−1, showcasing its significance in facilitating OER. Moreover, its mass activity surpasses that of commercial IrO2 by 5.1 times at 1.7 V. Prolonged constant current testing further demonstrates the exceptional stability of the catalyst, affirming the critical role of Ce doping as a pivotal strategy for enhancing the stability of supported Ir-based catalysts and advancing the prospects for robust OER performance in PEMWE systems.

Composition, microstructure, and ionic conductivity relationships in cerium doped Li0.5La0.5TiO3 solid electrolyte

The increasing necessity of high ionic conductor for solid state electrolytes implies the enhancement of our understanding in the relationship between doping-microstructure-ionic conductivity. In the current study, Li0.5La0.5-xCexTiO3 (0.00 ≤x ≤ 0.05) perovskites are obtained using the sol-gel method to evaluate the effects of cerium doping on microstructure and conductivity. The results confirms that all samples present a tetragonal perovskite structure with the lowest energy gap of 1.67eV for x = 0.01 of Ce3+, this particular composition present an average grain size of 2.026 μm and the highest relative density (92.02 %), bulk and grain boundary conductivities in the order of 1.949 × 10−3 S/cm and 1.671 × 10−6 S/cm, respectively at room temperature. These conductivity values are approximately an order of magnitude higher than the Ce-free material, thanks to the optimized relative density and adequate grain size.

Performance and Degradation of Electrolyte Supported SOECs with Advanced Thin-Film Gadolinium Doped Ceria Barrier Layers in Long-Term Stack Test

Electrolyte supported Solid Oxide Cells (ESCs) with advanced thin-film Gd-doped ceria diffusion barrier layers between electrolyte and electrodes were assembled and electrochemically investigated in steam electrolysis mode in a so-called “rainbow” stack with 30 repeat units (RUs). The barrier layers were deposited onto the electrolyte supports via electron-beam physical evaporation deposition (EB-PVD) method at 600 °C. In this paper, the investigation mainly focuses on the electrochemical characteristics of RUs containing the EB-PVD thin-film GDC layers. At the initial stage of the SOEC operation, the stack reached a high performance with an electrical efficiency of 99.65% at 75% steam conversion and a total power input of 1.98 kW. A long-term stack test was performed in SOEC mode for over 5000 h and demonstrated a low voltage degradation of approx. +11.3 mV·kh–1 per RU (+0.9% kh–1). The RUs with EB-PVD GDC thin-films revealed similar initial performance and degradation rate to the state-of-the-art cells with screen printed GDC layers.

Bimetallic Ni-Fe Supported by Gadolinium Doped Ceria (GDC) Catalyst for CO2 Methanation

CO2 conversion into fuels and high value-added chemical feedstocks, such as methane, has gained novel interest as a crucial process for further manufacturing multi-carbon products. Methane, CH4, becomes a promising alternative for environmental and energy supply issues. Nickel-based catalysts were found to be very active and selective for CH4 production. The use of promoter and support material to develop high activity, high selectivity, and durable catalysts for CO2 methanation at low temperature is a challenge. Gadolinium-Doped Ceria (GDC) has been known as material for Solid Oxide Fuel Cell (SOFC) and Solid Oxide Electrolysis Cell (SOEC) due to higher ionic conductivity and lower operating temperatures. However, few researches have been done regarding to CO2 methanation over GDC as catalyst support so far. In this present work, CO2 methanation was investigated over bimetallic Ni-Fe catalyst supported by GDC. The results showed that CH4 production rate by using Ni-Fe/GDC catalyst was higher than that of GDC at all reaction temperatures carried on. Ni-Fe/GDC showed remarkable CH4 production rate as of 17.73 mmol.gcat−1.h−1 at 280 °C. No catalytic activity was produced by GDC catalyst only. The highest CO2 conversion (46.50%) was observed at 280 °C, with almost 100% selectivity to CH4. The turnover frequency (TOF) value of Ni-Fe/GDC (4529.32 h−1) was the highest than that of Ni and common CO2 methanation catalyst, Ni/Al2O3 catalysts at 280 °C, further displaying the outstanding low-temperature catalytic activity. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

A High-Performance and Durable Direct-Ammonia Symmetrical Solid Oxide Fuel Cell with Nano La0.6Sr0.4Fe0.7Ni0.2Mo0.1O3-δ-Decorated Doped Ceria Electrode.

Solid oxide fuel cells (SOFCs) offer a significant advantage over other fuel cells in terms of flexibility in the choice of fuel. Ammonia stands out as an excellent fuel choice for SOFCs due to its easy transportation and storage, carbon-free nature and mature synthesis technology. For direct-ammonia SOFCs (DA-SOFCs), the development of anode catalysts that have efficient catalytic activity for both NH3 decomposition and H2 oxidation reactions is of great significance. Herein, we develop a Mo-doped La0.6Sr0.4Fe0.8Ni0.2O3-δ (La0.6Sr0.4Fe0.7Ni0.2Mo0.1O3-δ, LSFNM) material, and explore its potential as a symmetrical electrode for DA-SOFCs. After reduction, the main cubic perovskite phase of LSFNM remained unchanged, but some FeNi3 alloy nanoparticles and a small amount of SrLaFeO4 oxide phase were generated. Such reduced LSFNM exhibits excellent catalytic activity for ammonia decomposition due to the presence of FeNi3 alloy nanoparticles, ensuring that it can be used as an anode for DA-SOFCs. In addition, LSFNM shows high oxygen reduction reactivity, indicating that it can also be a cathode for DA-SOFCs. Consequently, a direct-ammonia symmetrical SOFC (DA-SSOFC) with the LSFNM-infiltrated doped ceria (LSFNM-SDCi) electrode delivers a superior peak power density (PPD) of 487 mW cm-2 at 800 °C when NH3 fuel is utilised. More importantly, because Mo doping greatly enhances the reduction stability of the material, the DA-SSOFC with the LSFN-MSDCi electrode exhibits strong operational stability without significant degradation for over 400 h at 700 °C.

Configurational entropy of cerate ceramics regulating by multicomponent rare earth for enhanced thermophysical properties

Cerate is regarded as a promising material for the next-generation of thermal barrier coating due to its high coefficient of thermal expansion (CTE) and low thermal conductivity. However, its thermal contraction within the temperature range of 473-673 K poses a significant challenge to its widespread application. The aim of this work is to improve the thermal contraction by regulating the configurational entropy of cerate ceramics. Six kinds of rare earth doped cerate ceramics with different configurational entropy were prepared. The results indicated that the phases of the as-prepared ceramics are all fluorite structures. With the increase of configurational entropy, the problem of thermal contraction is improved continuously. More importantly, the as-prepared (La1/8Sm1/8Yb1/8Y1/8Er1/8Eu1/8Nd1/8Gd1/8)2Ce2O7 (8RC) high entropy cerate ceramic demonstrates a near elimination of thermal contraction in the 473-673 K temperature range, and accompanied by high CTE, low thermal conductivity and good thermal stability, suggesting its potential application in the field of thermal barrier coating material.

Rare Earth Dopants Enhance Thermocatalytic Activity of Manganese Oxides on Corrugated Silica Carriers for Formaldehyde Degradation

AbstractThe development of high efficiency thermocatalysts remains a great challenge for gaseous formaldehyde elimination. Herein, rare earth‐doped manganese dioxide (RE‐MnO2) particles with sizes of approximately 200 nm were deposited on corrugated silica carrier (CSC) by using cerium or samarium as dopants. One part of rare earth ions in RE‐MnO2/CSC were substituted for the manganese ions in α‐MnO2, and the other part existed in the form of cerium oxide or samarium oxide. RE‐MnO2/CSC exhibited better thermocatalytic activity than MnO2/CSC. The formaldehyde removal efficiency over RE‐MnO2/CSC reached nearly 100 % even after cycle tests of 5 times. Both the cerium and samarium doping accelerated HCHO oxidation via increasing lattice oxygen and Mn4+ amounts, improving low‐temperature redox properties, and reducing apparent activation energy. Notably, the RE oxides in the catalysts played different roles in HCHO degradation. Samarium oxide did not possess thermocatalytic activity, while cerium oxide in RE‐MnO2/CSC participated directly in the formaldehyde degradation via the CeO2↔Ce2O3 redox reaction and facilitated the oxidation of Mn2O3 into MnO2. This work revealed the effect mechanisms of RE doping and RE oxide on the enhanced thermocatalytic activity, and provided a novel viewpoint to develop RE‐doped catalysts for formaldehyde removal.

Synthesis of nanoporous solid polymer electrolyte AuNiCe/NC hydrogenation membrane electrode

In this study, using graphite fiber cloth as the support, gold-based solid polymer electrolyte (SPE) membrane electrodes were synthesized by high-vacuum ion beam sputtering, nitrogen doping of the support, combined electrochemical dealloying, and hot-pressing technology. The application of the SPE membrane electrode to couple hydrogen evolution and liquid organic hydrogen storage is of significant importance for sustainable hydrogen energy and efficient carbon dioxide conversion. Using various characterization techniques, we systematically analyzed the phase structure, surface morphology, porous structure, and electrocatalytic performance of the membrane electrode for the hydrogenation of cyclohexene. The results indicated that doping the carbonaceous support with nitrogen (NC), doping with cerium as catalyst promoter, and combined electrochemical dealloying can all enhance the activity of the catalyst. Cerium doping provides the catalyst with oxygen vacancies for accelerated electron transfer. After combined electrochemical dealloying, AuNiCe/NC formed a three-dimensional bicontinuous porous structure. The electrochemically active surface area increased by 23.94 times, the energy consumption of catalytic cyclohexene hydrogenation decreased by 35.7%, and current efficiency and the formation rate of cyclohexane increased by 54.9% and 29.4%, respectively.