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Oxygen-deficient MoO/NiS heterostructure grown on nickel foam as efficient and durable self-supported electrocatalysts for hydrogen evolution reaction

《化学科学与工程前沿(英文)》 2023年 第17卷 第4期   页码 437-448 doi: 10.1007/s11705-022-2228-1

摘要: High-performance and ultra-durable electrocatalysts are vital for hydrogen evolution reaction (HER) during water splitting. Herein, by one-pot solvothermal method, MoOx/Ni3S2 spheres comprising Ni3S2 nanoparticles inside and oxygen-deficient amorphous MoOx outside in situ grow on Ni foam (NF), to assembly the heterostructure composites of MoOx/Ni3S2/NF. By adjusting volume ratio of the solvents of ethanol to water, the optimized MoOx/Ni3S2/NF-11 exhibits the best HER performance, requiring an extremely low overpotential of 76 mV to achieve the current density of 10 mA∙cm‒2 (η10 = 76 mV) and an ultra-small Tafel slope of 46 mV∙dec‒1 in 0.5 mol∙L‒1 H2SO4. More importantly, the catalyst shows prominent high catalytic stability for HER (> 100 h). The acid-resistant MoOx wraps the inside Ni3S2/NF to ensure the high stability of the catalyst under acidic conditions. Density functional theory calculations confirm that the existing oxygen vacancy and MoOx/Ni3S2 heterostructure are both beneficial to the reduced Gibbs free energy of hydrogen adsorption (|∆GH*|) over Mo sites, which act as main active sites. The heterostructure effectively decreases the formation energy of O vacancy, leading to surface reconstruction of the catalyst, further improving HER performance. The MoOx/Ni3S2/NF is promising to serve as a highly effective and durable electrocatalyst toward HER.

关键词: molybdenum oxides     oxygen vacancies     heterostructure     electrocatalysts     hydrogen evolution reaction    

Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using

Diana AMORELLO,Santino ORECCHIO

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 605-614 doi: 10.1007/s11783-014-0703-8

摘要: The main purpose of this work was to develop a reliable method for the determination of vanadium (V) and molybdenum (Mo) in atmosphere particles or aerosols because they can not be readily measured using conventional techniques. For this research, 30 particulate samples were collected from five different stations located at Palermo, Italy. We used the catalytic adsorptive stripping voltammetry and differential pulsed voltammetry to measure V and Mo in atmospheric particulate, respectively. The represented method includes advantages of high sensitivity, high selectivity, simplicity, reproducibility, speed and low costs. The quantification limits for V and Mo are, respectively, 0.57 and 0.80 ng·m . The precision, expressed as relative standard deviation (RSD %), was about 2% for both metals. The mean recoveries of added V and Mo were about 99.5% and ranged from 97% to 101%. Vanadium concentrations in particulate samples collected in Palermo area ranged from 0.57 to 7.7 ng·m , while Mo concentrations were in the range 0.8–51 ng·m . In many cases the concentrations of two elements in the particulate samples fall below the detection limits. The mean concentrations for V and Mo in particulate samples, collected in Palermo area, were respectively 3.1 and 5.9 ng·m .

关键词: vanadium     molybdenum     particulate     voltammetry     Palermo    

Catalytic combustion of volatile organic compounds using perovskite oxides catalysts—a review

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1649-1676 doi: 10.1007/s11705-023-2324-x

摘要: With the rapid development of industry, volatile organic compounds (VOCs) are gaining attention as a class of pollutants that need to be eliminated due to their adverse effects on the environment and human health. Catalytic combustion is the most popular technology used for the removal of VOCs as it can be adapted to different organic emissions under mild conditions. This review first introduces the hazards of VOCs, their treatment technologies, and summarizes the treatment mechanism issues. Next, the characteristics and catalytic performance of perovskite oxides as catalysts for VOC removal are expounded, with a special focus on lattice distortions and surface defects caused by metal doping and surface modifications, and on the treatment of different VOCs. The challenges and the prospects regarding the design of perovskite oxides catalysts for the catalytic combustion of VOCs are also discussed. This review provides a reference base for improving the performance of perovskite catalysts to treat VOCs.

关键词: perovskite oxides     volatile organic compounds     catalytic combustion     reaction mechanism    

Molybdenum disulfide@nickel phyllosilicate hybrid for improving the flame retardancy and wear resistance

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2114-2126 doi: 10.1007/s11705-023-2357-1

摘要: In this study, nickel phyllosilicate was synthesized based on molybdenum disulfide (MoS2@NiPS) by the sol-gel method, and then MoS2@NiPS was used to prepare epoxy composites. The thermal stability, flame retardancy, and frictional performances of epoxy composites were studied. With the addition of 3 wt% MoS2@NiPS, the epoxy composite increased the limiting oxygen index from 23.8% to 26.1% and reduced the vertical burning time from 166 s for epoxy resin to 35 s. The residual char of the epoxy composite increased from 11.8 to 20.2 wt%. MoS2@NiPS promoted the graphitization of the residual char, and facilitated the formation of a dense and continuous char layer, thereby improving the fire safety of epoxy resin. The epoxy composite with 3 wt% MoS2@NiPS had excellent wear resistance property with a wear rate of 2.19 × 10−5 mm3·N–1·m–1, which was 68.8% lower than that of epoxy resin. This study presented a practical approach to improve the frictional and fire resistance of epoxy composites.

关键词: molybdenum disulfide     nickel phyllosilicate     epoxy resin     flame retardancy    

Multivalent manganese oxides with high electrocatalytic activity for oxygen reduction reaction

Xiangfeng Peng, Zhenhai Wang, Zhao Wang, Yunxiang Pan

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 790-797 doi: 10.1007/s11705-018-1706-y

摘要: A noble-metal-free catalyst based on both Mn O and MnO was prepared by using the dielectric barrier discharge technique at moderate temperature. The prepared catalyst shows a higher electrocatalytic activity towards the oxygen reduction reaction than the catalyst prepared by using the traditional calcination process. The enhanced activity could be due to the coexistence of manganese ions with different valences, the higher oxygen adsorption capacity, and the suppressed aggregation of the catalyst nanoparticles at moderate temperature. The present work would open a new way to prepare low-cost and noble-metal-free catalysts at moderate temperature for more efficient electrocatalysis.

关键词: oxygen reduction reaction     manganese oxides     mixed valences of manganese     oxygen adsorption     dielectric barrier discharge    

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1255-8

摘要: • Mechanisms of redox reactions of Fe- and Mn-oxides were discussed. • Oxidative reactions of Mn- and Fe-oxides in complex systems were reviewed. • Reductive reaction of Fe(II)/iron oxides in complex systems was examined. • Future research on examining the redox reactivity in complex systems was suggested. Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn2+ , Ca2+, Ni2+, Cr3+ and Cu2+, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

关键词: Iron oxides     manganese oxides     reduction     oxidation     complex systems     reaction kinetics and mechanisms    

The role of manganese oxides in the activation of peroxymonosulfate (PMS)

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1158-8

摘要: Manganese oxides (MnOx) have been demonstrated to be effective materials to activate Oxone (i.e., PMS) to degrade various contaminants. However, the contribution of direct oxidation by MnOx to the total contaminant degradation under acidic conditions was often neglected in the published work, which has resulted in different and even conflicting interpretations of the reaction mechanisms. Here, the role of MnOx (as both oxidants and catalysts) in the activation of Oxone was briefly discussed. The findings offered new insights into the reaction mechanisms in PMS-MnOx and provided a more accurate approach to examine contaminant degradation for water/wastewater treatment.

关键词: Peroxymonosulfate     Manganese oxides     Catalyst     Oxidant    

Oxidative leaching kinetics of molybdenum-uranium ore in H

T. A. Lasheen, M. E. El-Ahmady, H. B. Hassib, A. S. Helal

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 95-102 doi: 10.1007/s11705-013-1317-6

摘要: The processing of molybdenum-uranium ore in a sulfuric acid solution using hydrogen peroxide as an oxidant has been investigated. The leaching temperature, hydrogen peroxide concentration, sulfuric acid concentration, leaching time, particle size, liquid-to-solid ratio and agitation speed all have significant effects on the process. The optimum process operating parameters were: temperature: 95°C; H O concentration: 0.5 M; sulfuric acid concentration: 2.5 M; time: 2 h; particle size: 74 μm, liquid-to-solid ratio: 14 ∶ 1 and agitation speed: 600 rpm. Under these experimental conditions, the extraction efficiency of molybdenum was about 98.4%, and the uranium extraction efficiency was about 98.7%. The leaching kinetics of molybdenum showed that the reaction rate of the leaching process is controlled by the chemical reaction at the particle surface. The leaching process follows the kinetic model 1 ? (1? ) = with an apparent activation energy of 40.40 kJ/mole. The temperature, concentrations of H O and H SO and the mesh size are the main factors that influence the leaching rate. The reaction order in H SO was 1.0012 and in H O it was 1.2544.

关键词: leaching of molybdenum     leaching of uranium     kinetics    

Water quality prediction of copper-molybdenum mining-beneficiation wastewater based on the PSO-SVR model

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1698-9

摘要:

● Data acquisition and pre-processing for wastewater treatment were summarized.

关键词: Chemical oxygen demand     Mining-beneficiation wastewater treatment     Particle swarm optimization     Support vector regression     Artificial neural network    

Review on research and application of mesoporous transitional metal oxides in water treatment

Minghao SUI, Lei SHE

《环境科学与工程前沿(英文)》 2013年 第7卷 第6期   页码 795-802 doi: 10.1007/s11783-013-0521-4

摘要: This paper reviews the application of mesoporous transitional metal oxides in water treatment on basis of the catalysis and adsorption. Mesoporous transitional metal oxides are characterized by their intrinsic features, such as a high surface area, a highly ordered array of unidimensional pores with a very narrow pore size distribution, and highly dispersed active sites. Finally, the suggestions of further study on application are proposed.

关键词: mesoporous materials     transitional metal oxides     catalysis     adsorption     water treatment    

Catalytic reduction of water pollutants: knowledge gaps, lessons learned, and new opportunities

《环境科学与工程前沿(英文)》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1626-z

摘要:

● Advances, challenges, and opportunities for catalytic water pollutant reduction.

关键词: Molybdenum     Rhenium     Rhodium     Ruthenium     Catalyst Support     Bromate    

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1211-1223 doi: 10.1007/s11705-022-2145-3

摘要: The one-step highly selective oxidation of cyclohexane into cyclohexanone and cyclohexanol as the essential intermediates of nylon-6 and nylon-66 is considerably challenging. Therefore, an efficient and low-cost catalyst must be urgently developed to improve the efficiency of this process. In this study, a Co3O4–CeO2 composite oxide catalyst was successfully prepared through ultrasound-assisted co-precipitation. This catalyst exhibited a higher selectivity to KA-oil, which was benefited from the synergistic effects between Co3+/Co2+ and Ce4+/Ce3+ redox pairs, than bulk CeO2 and/or Co3O4. Under the optimum reaction conditions, 89.6% selectivity to KA-oil with a cyclohexane conversion of 5.8% was achieved over Co3O4–CeO2. Its catalytic performance remained unchanged after five runs. Using the synergistic effects between the redox pairs of different transition metals, this study provides a feasible strategy to design high-performance catalysts for the selective oxidation of alkanes.

关键词: Co3O4–CeO2 composite oxides     cyclohexanone     cyclohexanol     ultrasonic-assisted co-precipitation     selective oxidation     solvent-free    

Fluoride ions adsorption from water by CaCO enhanced Mn–Fe mixed metal oxides

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 236-248 doi: 10.1007/s11705-022-2193-8

摘要: Novel CaCO3-enhanced Mn–Fe mixed metal oxides (CMFC) were successfully prepared for the first time by a simple-green hydrothermal strategy without any surfactant or template combined with calcination process. These oxides were then employed as an adsorbent for adsorptive removal of excess fluoride ions. The adsorbent was characterized by SEM, XPS, XRD, FTIR, and BET analysis techniques. The adsorption property of CMFC toward fluoride ion was analyzed by batch experiments. In fact, CMFC exhibited adsorption capacity of 227.3 mg∙g‒1 toward fluoride ion. Results showed that ion exchange, electrostatic attraction and chemical adsorption were the main mechanism for the adhesion of large amount of fluoride ion on the CMFC surface, and the high adsorption capacity responded to the low pH of the adsorption system. When the fluoride ion concentration was increased from 20 to 200 mg∙L‒1, Langmuir model was more in line with experimental results. The change of fluoride ion adsorption with respect to time was accurately described by pseudo-second-order kinetics. After five cycles of use, the adsorbent still maintains a performance of 70.6% of efficiency, compared to the fresh adsorbent. Therefore, this material may act as a potential candidate for adsorbent with broad range of application prospects.

关键词: mesoporous materials     metal oxides     fluoride ion     adsorption mechanism    

Application of metal oxides-based nanofluids in PV/T systems: a review

《能源前沿(英文)》 2022年 第16卷 第3期   页码 397-428 doi: 10.1007/s11708-021-0758-8

摘要: Having the wide application of metal oxides in energy technologies, in recent years, many researchers tried to increase the performance of the PV/T system by using metal oxide-based nanofluids (NFs) as coolants or optical filters or both at the same time. This paper summarizes recent research activities on various metal oxides (Al2O3, TiO2, SiO2, Fe3O4, CuO, ZnO, MgO)-based NFs performance in the PV/T system regarding different significant parameters, e.g., thermal conductivity, volume fraction, mass flowrate, electrical, thermal and overall efficiency, etc. By conducting a comparative study among the metal oxide-based NFs, Al2O3/SiO2-water NFs are mostly used to achieve maximum performance. The Al2O3-water NF has a prominent heat transfer feature with a maximum electrical efficiency of 17%, and a maximum temperature reduction of PV module of up to 36.9°C can be achieved by using the Al2O3-water NF as a coolant. Additionally, studies suggest that the PV cell’s efficiency of up to 30% can be enhanced by using a solar tracking system. Besides, TiO2-water NFs have been proved to have the highest thermal efficiency of 86% in the PV/T system, but TiO2 nanoparticles could be hazardous for human health. As a spectral filter, SiO2-water NF at a size of 5 nm and a volume fraction of 2% seems to be very favorable for PV/T systems. Studies show that the combined use of NFs as coolants and spectral filters in the PV/T system could provide a higher overall efficiency at a cheaper rate. Finally, the opportunities and challenges of using NFs in PV/T systems are also discussed.

关键词: metal oxide     nanofluids (NFs)     nanoparticles (NPs)     optical filter     PV/T systems     solar energy    

Crystalline mesoporous transition metal oxides: hard-templating synthesis and application in environmental

Zhen MA, Bei ZHOU, Yu REN

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 341-355 doi: 10.1007/s11783-012-0472-1

摘要: Mesoporous silicas such as MCM-41 and SBA-15 possess high surface areas, ordered nanopores, and excellent thermal stability, and have been often used as catalyst supports. Although mesoporous metal oxides have lower surface areas compared to mesoporous silicas, they generally have more diversified functionalities. Mesoporous metal oxides can be synthesized via a soft-templating or hard-templating approach, and these materials have recently found some applications in environmental catalysis, such as CO oxidation, N O decomposition, and elimination of organic pollutants. In this review, we summarize the synthesis of mesoporous transition metal oxides using mesoporous silicas as hard templates, highlight the application of these materials in environmental catalysis, and furnish some prospects for future development.

关键词: mesoporous materials     silica     metal oxide     hard-templating     environmental catalysis    

标题 作者 时间 类型 操作

Oxygen-deficient MoO/NiS heterostructure grown on nickel foam as efficient and durable self-supported electrocatalysts for hydrogen evolution reaction

期刊论文

Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using

Diana AMORELLO,Santino ORECCHIO

期刊论文

Catalytic combustion of volatile organic compounds using perovskite oxides catalysts—a review

期刊论文

Molybdenum disulfide@nickel phyllosilicate hybrid for improving the flame retardancy and wear resistance

期刊论文

Multivalent manganese oxides with high electrocatalytic activity for oxygen reduction reaction

Xiangfeng Peng, Zhenhai Wang, Zhao Wang, Yunxiang Pan

期刊论文

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

期刊论文

The role of manganese oxides in the activation of peroxymonosulfate (PMS)

Jianzhi Huang, Huichun Zhang

期刊论文

Oxidative leaching kinetics of molybdenum-uranium ore in H

T. A. Lasheen, M. E. El-Ahmady, H. B. Hassib, A. S. Helal

期刊论文

Water quality prediction of copper-molybdenum mining-beneficiation wastewater based on the PSO-SVR model

期刊论文

Review on research and application of mesoporous transitional metal oxides in water treatment

Minghao SUI, Lei SHE

期刊论文

Catalytic reduction of water pollutants: knowledge gaps, lessons learned, and new opportunities

期刊论文

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective

期刊论文

Fluoride ions adsorption from water by CaCO enhanced Mn–Fe mixed metal oxides

期刊论文

Application of metal oxides-based nanofluids in PV/T systems: a review

期刊论文

Crystalline mesoporous transition metal oxides: hard-templating synthesis and application in environmental

Zhen MA, Bei ZHOU, Yu REN

期刊论文