Browse
Submit Data
Databases
API
Help

Dataset Information

14 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Effect of Ce doping on the structure-activity relationship of MoVO _x composite metal oxides.

ABSTRACT: A series of Ce-doped MoVO _x composite metal oxide catalysts were prepared by the rotary evaporation method. The effects of Ce doping ratio on the crystal phase composition, morphology and surface properties of the catalysts were investigated. The results show that the crystal phase composition of samples with different Ce doping content is also obviously different. When the doping amount is small, V_0.95Mo_0.97O₅ is the main crystal phase, while MoO₃ is dominant when the doping amount is large. The Ce-doped catalyst showed obvious rod-shaped morphology and its average single point pore diameter and the number of acidic sites increased. Compared to the un-doped MoVO _x , the pore size of the sample synthesized at a Mo/Ce atomic ratio of 10/1 exhibited an increase of 41.11 nm. In addition, the effect of Ce doping on the catalytic performance of MoVO _x was investigated with the selective oxidation of benzyl alcohol as a probe reaction. After doping, the MoVO _x catalyst showed improved benzyl alcohol conversion and selectivity to benzaldehyde. At a Mo/Ce atomic ratio of 10/1, the conversion rate of benzyl alcohol reaches 83.26%, which is 64.56% higher than that without doping, and the highest product yield can reach 76.47%.

SUBMITTER: Deng L

PROVIDER: S-EPMC9043333 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Preparation of Ce⁻Mn Composite Oxides with Enhanced Catalytic Activity for Removal of Benzene through Oxalate Method.

Project description:The catalytic activities of CeO₂-MnOx composite oxides synthesized through oxalate method were researched. The results exhibited that the catalytic properties of CeO₂-MnOx composite oxides were higher than pure CeO₂ or MnOx. When the Ceat/Mnat ratio was 3:7, the catalytic activity reached the best. In addition, the activities of CeO₂-MnOx synthesized through different routes over benzene oxidation were also comparative researched. The result indicated that the catalytic property of sample prepared by oxalate method was better than others, which maybe closely related with their meso-structures. Meanwhile, the effects of synergistic interaction and oxygen species in the samples on the catalytic ability can't be ignored.

| S-EPMC6409587 | biostudies-literature

Band structure engineering of NiS2 monolayer by transition metal doping.

Project description:By using density functional theory calculations, we have studied the effects of V-, Cr-, Mn-, Fe- and Co-doped on the electronic and magnetic properties of the 1T-NiS2 monolayer. The results show that pure 1T-NiS2 monolayer is a non-magnetic semiconductor. Whereas depending on the species of transition metal atom, the substituted 1T-NiS2 monolayer can become a magnetic semiconductor (Mn-doped), half-metal (V- and Fe-doped) and magnetic (Cr-doped) or non-magnetic (Co-doped) metal. The results indicate that the magnetism can be controlled by the doping of 3d transition metal atoms on the monolayer. In this paper, the engineering of the electric and magnetic properties of 1T-NiS2 monolayer is revealed. It is clear that it could have a promising application in new nanoelectronic and spintronic devices.

| S-EPMC7952594 | biostudies-literature

High-yield synthesis of Ce modified Fe-Mn composite oxides benefitting from catalytic destruction of chlorobenzene.

Project description:Ce-Fe-Mn catalysts were prepared by an oxalic acid assisted co-precipitation method. The influence of Ce doping and calcination temperature on the catalytic oxidation of chlorobenzene (as a model VOC molecule) was investigated in a fixed bed reactor. The Mn3O4 phase was formed in Ce-Fe-Mn catalysts at low calcination temperatures (<400 °C), which introduced more chemisorbed oxygen, and enhanced the mobility of O atoms, resulting in an improvement of the reduction active of Mn3O4 and Fe2O3. Additionally, CeO2 has strong redox properties, and Ce4+ would oxidize Mn x+ and Fe x+. Therefore, the interaction of Ce, Fe and Mn can improve the content of surface chemisorbed oxygen. As compared with Fe-Mn catalysts, the catalytic conversion of chlorobenzene over Ce(5%)-Fe-Mn-400 was about 99% at 250 °C, owing to high specific surface area, Mn3O4 phase, and Ce doping. However, with the increase in roasting temperature, the performance of the catalysts for the catalytic combustion of chlorobenzene was decreased, which probably accounts for the formation of the Mn2O3 phase in Ce-Fe-Mn-500 catalysts, leading to a decrease in the specific surface area and concentration of chemically adsorbed oxygen. As a result, it can be expected that the Ce-Fe-Mn catalysts are effective and promising catalysts for chlorobenzene destruction.

| S-EPMC9050221 | biostudies-literature

Synthesis of core-shell Ce-modified mixed metal oxides derived from P123-templated layered double hydroxides.

Project description:Layered double hydroxides are a promising platform material which can be combined with a variety of active species based on their characteristic features. Silicon@P123-templated Ce-doped layered double hydroxide (SiO2@CeMgAl-LDH(P123)) composites were synthesized via a facile in situ co-precipitation method, and characterized by TEM, X-ray diffraction, FTIR, XPS, CO2-, etc. in detail. Meanwhile, the calcined powder (SiO2@CeMgAl-LDO(P123)) possessed an excellent core-shell structure and a high surface area inherited from the LDH structure, which led to an outstanding catalytic activity (99.7% conversion of propylene oxide, 92.4% selectivity of propylene glycol methyl ether) under mild reaction conditions (120 °C). Cerium oxide provides a large number of oxygen vacancies and significantly improves the medium basic strength of the material, which facilitates the selective ring-opening of PO. Furthermore, the introduction and removal of P123 make the cerium oxide uniformly dispersed on the LDH layers, providing more reaction sites for the reaction of methanol and propylene oxide. The core-shell structure prepared by the in situ co-precipitation method could solve the shortcomings of agglomeration of layered double hydroxides and prolong the catalytic life evidently.

| S-EPMC8695133 | biostudies-literature

Decomposition of SO2 on Ni(111) Surface and the Effect of Metal Doping: A First-Principles Study.

Project description:Sulfides poisoning of metallic Ni is an important issue in catalyst deactivation. SO2, similar to H2S and other sulfides, is an impurity presented in reactants or during the regeneration steps. Herein, spin-polarized density functional theory calculations were used to study the adsorption and decomposition of SO2 on a pristine and metal-doped Ni(111) surface. The adsorption energy, transition state energy, and partial density of state (PDOS) were calculated. On the pristine Ni(111) surface, ten different configurations were considered, and three typical ones were selected for transition state searching. It was found that the reaction barrier of the first S-O bond dissociation was much higher than that of the second one. Doping the top layer with a second metal could strongly change the adsorption and decomposition behavior. Doping with 3/9ML Co slightly increases the adsorption energy of SO2 for most configurations and decreases the reaction barriers of the SO2-tht-2 decomposition, while the others decrease the adsorption ability and increase the barriers. The order of adsorption energy for the most stable configurations is Co > Ni > Cu > Rh > Pd. The order of the first S-O bond dissociation reaction barriers is Pd > Rh > Cu = Ni > Co, and the order of the second bond dissociation barrier is Rh > Pd > Cu > Ni > Co.

| S-EPMC10536407 | biostudies-literature

Engineering the Electronic Structure towards Visible Lights Photocatalysis of CaTiO3 Perovskites by Cation (La/Ce)-Anion (N/S) Co-Doping: A First-Principles Study.

Project description:Cation-anion co-doping has proven to be an effective method of improving the photocatalytic performances of CaTiO3 perovskites. In this regard, (La/Ce-N/S) co-doped CaTiO3 models were investigated for the first time using first-principles calculations based on a supercell of 2 × 2 × 2 with La/Ce concentrations of 0.125, 0.25, and 0.375. The energy band structure, density of states, charge differential density, electron-hole effective masses, optical properties, and the water redox potential were calculated for various models. According to our results, (La-S)-doped CaTiO3 with a doping ratio of 0.25 (LCOS1-0.25) has superior photocatalytic hydrolysis properties due to the synergistic performances of its narrow band gap, fast carrier mobility, and superb ability to absorb visible light. Apart from the reduction of the band gap, the introduction of intermediate energy levels by La and Ce within the band gap also facilitates the transition of excited electrons from valence to the conduction band. Our calculations and findings provide theoretical insights and solid predictions for discovering CaTiO3 perovskites with excellent photocatalysis performances.

| S-EPMC10608951 | biostudies-literature

Heterogeneous Reaction of SO2 on Manganese Oxides: the Effect of Crystal Structure and Relative Humidity.

Project description:Manganese oxides from anthropogenic sources can promote the formation of sulfate through catalytic oxidation of SO2. In this study, the kinetics of SO2 reactions on MnO2 with different morphologies (?, ?, ? and ?) was investigated using flow tube reactor and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Under dry conditions, the reactivity towards SO2 uptake was highest on ?-MnO2 but lowest on ?-MnO2, with a geometric uptake coefficient (?obs) of (2.42?±?0.13) ×10-2 and a corrected uptake coefficient (?c) of (1.48?±?0.21) ×10-6 for the former while ?obs of (3.35?±?0.43) ×10-3 and ?c of (7.46?±?2.97) ×10-7 for the latter. Under wet conditions, the presence of water altered the chemical form of sulfate and was in favor for the heterogeneous oxidation of SO2. The maximum sulfate formation rate was reached at 25% RH and 45% for ?-MnO2 and ?-MnO2, respectively, possibly due to their different crystal structures. The results suggest that morphologies and RH are important factors influencing the heterogeneous reaction of SO2 on mineral aerosols, and that aqueous oxidation process involving transition metals of Mn might be a potential important pathway for SO2 oxidation in the atmosphere.

| S-EPMC5495761 | biostudies-literature

Enhanced electrocatalytic reduction of CO2 to formate via doping Ce in Bi2O3 nanosheets.

Project description:Formate is considered as the most economically viable product of the prevalent electrochemical CO2 reduction (ECR) products. However, most of the catalysts for ECR to formate in aqueous solution often suffer from low activity and limited selectivity. Herein, we report a novel Ce-doped Bi2O3 nanosheet (NS) electrocatalyst by a facile solvothermal method for highly efficient ECR to formate. The 5.04% Ce-doped Bi2O3 NSs exhibited a current density of 37.4 mA cm-2 for the production of formate with a high formate faradaic efficiency (FE) of 95.8% at -1.12 V. The formate FE was stably maintained at about 90% in a wide potential range from -0.82 to -1.22 V. More importantly, density functional theory (DFT) calculations revealed that Ce doping can lead to a significant synergistic effect, which promotes the formation and the adsorption of the OCHO* intermediate for ECR, while significantly inhibiting the hydrogen evolution reaction via depressing the formation of *H, thus helping achieve high current density and FE. This work provides an effective and promising strategy to develop efficient electrocatalysts with heteroatom doping and new insights for boosting ECR into formate.

| S-EPMC9417881 | biostudies-literature

Rhodium doping augments photocatalytic activity of barium titanate: effect of electronic structure engineering.

Project description:Environmentally friendly BaTiO3 is emerging as a potential photocatalyst due to its tunable electronic structure. Although originally believed to be a poor photocatalyst due to its wide band gap, several strategies have been implemented to reduce its band gap. One such approach is doping, but this often leads to the formation of mid gap recombination centers and diminishes the efficiency of the material. In the present work, we study for the first time the effect of site occupancy of Rh on the electronic structure of BaTiO3. As the theoretical results reveal that if Rh occupies both Ba and Ti sites simultaneously it leads to the formation of mid gap states, an experimental approach is implemented to reduce the band gap of BaTiO3 while simultaneously avoiding the formation of recombination centers. The facile one pot hydrothermal approach reported here directs the Rh towards Ba sites leading to a decrease in the band gap due to the appearance of donor Rh3+ states, suppressing the formation of Rh4+ states. A promising photocatalytic activity of 96% degradation of methylene blue dye in 120 minutes was observed for the 0.5 Rh sample indicating the high efficiency of the material.

| S-EPMC9418416 | biostudies-literature

Environment-friendly magnetic Fe-Ce-W catalyst for the selective catalytic reduction of NO x with NH3: influence of citric acid content on its activity-structure relationship.

Project description:The influence of the citric acid content on the structural and redox properties of a magnetic iron-cerium-tungsten mixed oxide catalyst prepared through a microwave-assisted citric acid sol-gel method is investigated via TG-DTG-DSC, XRD, N2 adsorption-desorption, XPS, H2-TPR and NH3-TPD. Additionally, the NH3-SCR activity of the magnetic FeCeW-m (m = 0.25, 0.5 and 1.0) catalysts are also studied. The results indicate that an increase in citric acid content strengthens the sol-gel reaction between citric acid and metal ions and promotes the formation of the γ-Fe2O3 crystallite not α-Fe2O3. Meanwhile, it decreases the BET surface area and pore volume of the catalyst. Furthermore, the surface concentration of iron species on the catalyst is enhanced when the molar ratio of citric acid/(Fe + Ce + W) increases from 0.25 to 1.0, but its surface absorbed oxygen and total oxygen concentration decrease. The magnetic FeCeW-0.5 catalyst shows the best reducibility at temperatures below 790 °C. The increase in the citric acid content inhibits the formation of acid sites in the catalyst, thus the magnetic FeCeW-0.25 catalyst possesses the most Lewis acid sites and Brønsted acid sites among the catalysts. The enhancement in citric acid content is beneficial to improve the SCR reaction rates normalized by the surface area of the catalyst. This catalyst exhibits high anti-SO2 and H2O poisoning, and the molar ratio of citric acid/(Fe + Ce + W) affects the adsorption of NO x species on its surface.

| S-EPMC9081273 | biostudies-literature