Influence of solution pH on the formation of iron oxide nanoparticles

Suppiah, Durga Devi; Johan, Mohd Rafie

doi:10.1088/2053-1591/aae428

Cited by 16 publications

(5 citation statements)

References 19 publications

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“…[ 25 ] The alkaline environment during dopamine treatment may also have contributed to crystallinity, as the pH of the reaction solution is well known to affect the crystallinity of the nanomaterial formed. [ 26 ] However, further study on this seems out of the scope of the present work, mainly because the optimum and the most efficient polydopamine coating can be achieved at a pH of 8 to 8.5, rendering the variable pH study redundant. [ 16 , 27 ] In addition to the CoMoS 3.1 peaks, the appearance of the carbon peak near 26.5° corresponds to the (002) lattice plane of carbon and again verifies its presence in the composite.…”

Section: Resultsmentioning

confidence: 99%

Synergistic Performance Boosts of Dopamine‐Derived Carbon Shell Over Bi‐metallic Sulfide: A Promising Advancement for High‐Performance Lithium‐Ion Battery Anodes

Bhattarai,

Le,

Chhetri

et al. 2024

Advanced Science

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A CoMoS composite is synthesized to combine the benefits of cobalt and molybdenum sulfides as an anodic material for advanced lithium‐ion batteries (LIBs). The synthesis is accomplished using a simple two‐step hydrothermal method and the resulting CoMoS nanocomposites are subsequently encapsulated in a carbonized polydopamine shell. The synthesis procedure exploited the self‐polymerization ability of dopamine to create nitrogen‐doped carbon‐coated cobalt molybdenum sulfide, denoted as CoMoS@NC. Notably, the de‐lithiation capacity of CoMoS and CoMoS@NC is 420 and 709 mAh g⁻1, respectively, even after 100 lithiation/de‐lithiation cycles at a current density of 200 mA g⁻1. Furthermore, excellent capacity retention ability is observed for CoMoS@NC as it withstood 600 consecutive lithiation/de‐lithiation cycles with 94% capacity retention. Moreover, a LIB full‐cell assembly incorporating the CoMoS@NC anode and an NMC‐532 cathode is subjected to comprehensive electrochemical and practical tests to evaluate the performance of the anode. In addition, the density functional theory showcases the increased lithium adsorption for CoMoS@NC, supporting the experimental findings. Hence, the use of dopamine as a nitrogen‐doped carbon shell enhanced the performance of the CoMoS nanocomposites in experimental and theoretical tests, positioning the material as a strong candidate for LIB anode.

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Section: Resultsmentioning

confidence: 99%

Synergistic Performance Boosts of Dopamine‐Derived Carbon Shell Over Bi‐metallic Sulfide: A Promising Advancement for High‐Performance Lithium‐Ion Battery Anodes

Bhattarai,

Le,

Chhetri

et al. 2024

Advanced Science

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“…It is considered that the color changes of soils and weathering crusts can indicate different proportions of goethite and hematite and infer climate in various ways [37]. The former reports suggested that relatively high temperatures and low humidity are suitable formation conditions that are beneficial to form hematite, while goethite is present in cool, humid climates [24,[37][38][39]. They can transform into each other when the climate changes [37,40].…”

Section: Discussionmentioning

confidence: 99%

The Color Formation of “Lumu Stone” in the Weathering Processes: The Role of Secondary Hematite and Goethite

Zheng

Chen

Han³

et al. 2023

Minerals

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Rocks and minerals buried in the earth’s surface usually undergo weathering processes and change color in the burying environment. A kind of yellow Chinese stamp stone named “Lumu stone”, which is buried in a yellowish weathering crust (yellowish soil), was selected to investigate its color changes in the weathering processes. In this study, the appearance features, mineral components, micromorphology, spectroscopy characteristics, and color causation of the “Lumu stone” were studied by using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), an electron probe microanalyzer (EPMA), a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS), and a UV-Visible (UV-Vis) spectrum. The “Lumu stone” usually exhibits a darker yellow outer layer and a lighter yellow core, suggesting that yellow color permeated into the stone from the surface to the core gradually and the color is secondary forming. The results from XRD and SEM show the studied samples are mainly composed of dickite and illite. The individual particles of the dickite and illite are about 2–5 μm, randomly distributing in the three-dimensional space and constituting voids among the particles. The acid pickling experiments using HCl coupled with KSCN confirmed that the mineral phases that caused the yellow color of the matrix are iron oxide and hydroxide. On the other hand, goethite and hematite were observed gathering in the yellow and brown-red cracks on the “Lumu stone” by SEM study. However, iron oxide and hydroxide in the matrix were difficult to observe and detect among the dickite and illite aggregates by SEM and XRD methods. It indicates that they may be nanoscale in size and very low in content. According to the calculation of the second derivative of Kubelka-Munk (K-M) transformed diffuse reflection spectroscopy (DRS) curves obtained from UV-Vis, the characteristic peaks of goethite and hematite were found in the yellow matrix, and their contributions to the color were confirmed. The concentrations of goethite and hematite were calculated to be 0.32 to 1.87 g/kg and 0.22 to 0.93 g/kg in the studied samples, respectively. In this study, a series of methods were employed to detect very low levels of goethite and hematite in the samples undergoing weathering processes. Additionally, nanoscale goethite and hematite were considered newly formed minerals when buried in the weathering processes and may gradually move into the voids among phyllosilicate particles. Therefore, they turned the “Lumu stone” yellow.

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“…Shape and size control is determined by the synthesis solution pH, which acts as the structure-directing agent, hence influencing the oxidation rate, giving 16 different pure phases of iron oxides. 23,24 The most commonly used iron catalyst phase for CO 2 FT synthesis is magnetite (Fe 3 O 4 ), which can be easily synthesized by co-precipitation by altering the pH and ionic strength, ultimately influencing the nucleation process. 25 Recently, Li et al proposed a CO hydrogenation mechanism using the Fe (110) planar structure.…”

Section: Metal-based Fischer−tropsch Synthesis (Fts) Catalystmentioning

confidence: 99%

“…The iron oxide nanoparticle intrinsic physicochemical properties, such as a larger surface area, provide a higher number of active sites for CO 2 adsorption–desorption. Shape and size control is determined by the synthesis solution pH, which acts as the structure-directing agent, hence influencing the oxidation rate, giving 16 different pure phases of iron oxides. , …”

Section: Metal-based Fischer–tropsch Synthesis (Fts) Catalystmentioning

confidence: 99%

Supported Metal Oxide Catalysts for CO₂ Fischer–Tropsch Conversion to Liquid Fuels─A Review

2021

Self Cite

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The global increase of greenhouse gas carbon dioxide (CO 2 ) affects the balance of the atmosphere by contributing vastly to global warming. CO 2 hydrogenation is an attractive way to use CO 2 for value-added product generation. Direct CO 2 conversion to synthetic fuels or gasoline fuel, although challenging, is deemed effective in reducing CO 2 . The adsorption energy of CO 2 on the catalyst surface is the limiting factor; hence, the metal−support interaction is established as key in formulating a catalyst with superior performance. Typically iron oxide catalysts were commonly used as a Fischer−Tropsch catalyst, although the CO 2 conversion is relatively low. This review aims to highlight the importance of choosing the most suitable support with desired acidity and reduction capability for adequate interaction with catalyst active sites to enhance the activity and selectivity of the existing metal oxide catalyst. Support incorporation methods on the surface metal−support interaction are also scrutinized and accompanied by the reaction parameters for higher conversion, and reactor setup parameters that may have influenced the selectivity are analyzed.

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Influence of solution pH on the formation of iron oxide nanoparticles

Cited by 16 publications

References 19 publications

Synergistic Performance Boosts of Dopamine‐Derived Carbon Shell Over Bi‐metallic Sulfide: A Promising Advancement for High‐Performance Lithium‐Ion Battery Anodes

Synergistic Performance Boosts of Dopamine‐Derived Carbon Shell Over Bi‐metallic Sulfide: A Promising Advancement for High‐Performance Lithium‐Ion Battery Anodes

The Color Formation of “Lumu Stone” in the Weathering Processes: The Role of Secondary Hematite and Goethite

Supported Metal Oxide Catalysts for CO₂ Fischer–Tropsch Conversion to Liquid Fuels─A Review

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Influence of solution pH on the formation of iron oxide nanoparticles

Cited by 16 publications

References 19 publications

Synergistic Performance Boosts of Dopamine‐Derived Carbon Shell Over Bi‐metallic Sulfide: A Promising Advancement for High‐Performance Lithium‐Ion Battery Anodes

Synergistic Performance Boosts of Dopamine‐Derived Carbon Shell Over Bi‐metallic Sulfide: A Promising Advancement for High‐Performance Lithium‐Ion Battery Anodes

The Color Formation of “Lumu Stone” in the Weathering Processes: The Role of Secondary Hematite and Goethite

Supported Metal Oxide Catalysts for CO2 Fischer–Tropsch Conversion to Liquid Fuels─A Review

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Supported Metal Oxide Catalysts for CO₂ Fischer–Tropsch Conversion to Liquid Fuels─A Review