Iron Nitrate Nonahydrate Research Articles

Influence of inevitable iron precursor anions on MIL-100(Fe) structure and its La(Ⅲ) adsorption performance

The influence of iron precursor anions on the structure and properties of MIL-100(Fe) has often been overlooked. In this study, iron chloride hexahydrate and iron nitrate nonahydrate were used to synthesize MIL-100(Fe)-Cl and MIL-100(Fe)-N, respectively. Characterization comparisons revealed that MIL-100(Fe)-Cl exhibited a higher organic ligand content and a larger specific surface area. Subsequently, the adsorption properties of both materials for the rare-earth element lanthanum (La(Ⅲ)) were investigated. MIL-100(Fe)-Cl demonstrated superior La(Ⅲ) adsorption performance, with a maximum adsorption capacity of 54.7 mg·g−1, which is more than twice that of MIL-100(Fe)-N at 25.5 mg·g−1. The adsorption rate of MIL-100(Fe)-Cl for low-concentration La(Ⅲ) approached 100 % and sustained effective adsorption under weakly acidic conditions. The La(Ⅲ) adsorption processes on MIL-100(Fe)-Cl and MIL-100(Fe)-N were spontaneous and endothermic, involving both physisorption and chemisorption. Notably, a strong chemical interaction occurred during La(Ⅲ) adsorption by MIL-100(Fe)-Cl, whereas ion exchange was predominant in MIL-100(Fe)-N. Through further exploration of the adsorption mechanism via FT-IR and XPS characterizations, the main chemical active sites were the uncoordinated –COOH and terminal –OH groups of the Fe trimer. This study underscores the significant impact of different iron precursors on the synthesis of MIL-100(Fe), highlighting the need for careful selection of these materials in precursor choice.

High-performance nickel/iron catalysts for oxygen evolution in pH-near-neutral borate electrolyte synthesized by mechanochemical approach

In this work, a novel method of mechanochemistry is used to directly prepare high-performance Ni-Fe based catalysts for oxygen evolution reaction (OER) in an environmental-friendly borate electrolyte with near-neutral pH. Such a procedure is simple, effective, and time-saving. The effect of iron-based raw materials and mechanochemical reaction on OER of catalysts are investigated. It shows that iron nitrate nonahydrate is the best iron resource compared to iron hydroxide and iron oxide due to amorphous iron species in catalysts for strengthening the “Fe inductive effect” and generating active Ni species with high valence. Besides, the grinding time can control the mechanochemical reaction from mixed reaction to solid reaction in the catalyst synthesis process. When the time is 30 min, the catalyst is composed with amorphous Ni(OH)2 and the precursors of NiFe-LDH. This catalyst only needs 413 mV overpotential to reach 1 mA cm−2 in 0.1 M K-Bi (pH=9.2), which is better than precious RuO2. It is proven that the mechanochemical approach is an alternative method for synthesizing superior OER catalysts.

P-Type Chemical Doping-Induced High Bipolar Electrical Conductivities in a Thermoelectric Donor–Acceptor Copolymer

P-Type Chemical Doping-Induced High Bipolar Electrical Conductivities in a Thermoelectric Donor–Acceptor Copolymer

Confined space self-propagating room temperature synthesis of carbon-encapsulated Fe3O4 nanocrystals and its lithium storage performance

A self-propagating reaction between ferrocene and iron nitrate nonahydrate that is initiated at room temperature is discovered. Amorphous carbon-encapsulated Fe3O4 nanocrystals (Fe3O4@C) can be one-step prepared in an autoclave through this reaction. The equiaxed Fe3O4 nanocrystals have typical dimensions in the range of 5–60 nm with a median size of 24.1 nm, and their weight percent is up to 82.3%. The course of the reaction is recorded, and the formation mechanism of Fe3O4@C with the core–shell structure is proposed. The scaling-up synthesis is also achieved, and 52.1 g of the Fe3O4@C can be obtained in a single batch. The shock wave appeared in the fast gas release self-propagating reaction in confined space plays a decisive role in the preparation of homogeneous Fe3O4@C with a core–shell structure. The Fe3O4@C anode shows excellent capacity retention with a high specific capacity of 494 mAh g−1 at 1 A g−1 in the 200th cycle.

The Preparation of Iron Oxide Nanoparticles by a Self-combustion Method

This paper deals with problematic of preparation of iron oxide nanoparticles according to a self-combustion method. Iron oxide nanoparticles can be used e.g. for catalysators and gas sensors or in MRI. The Self-combustion method is based on rapid chemical reaction between a fuel and iron oxide precursor. Glycine, urea and citric acid were used as fuels and iron nitrate nonahydrate was used as an iron oxide precursor. The self-combustion method doesn't require any special equipment, is environment-friendly due to minimize pollution and the results are easily reproducible. The shape, size, and phase of resulting particles were investigated studied using scanning electron microscopy and energy-dispersive analysis.

Iron Oxide Silica Derived from Sol-Gel Synthesis.

In this work we investigate the effect of iron oxide embedded in silica matrices as a function of Fe/Si molar ratio and sol pH. To achieve homogeneous dispersion of iron oxide particles, iron nitrate nonahydrate was dissolved in hydrogen peroxide and was mixed with tetraethyl orthosilicate and ethanol in a sol-gel synthesis method. Increasing the calcination temperature led to a reduction in surface area, although the average pore radius remained almost constant at about 10 Å, independent of the Fe/Si molar ratio or sol pH. Hence, the densification of the matrix was accompanied by similar reduction in pore volume. However, calcination at 700 °C resulted in samples with similar surface area though the iron oxide content increased from 5% to 50% Fe/Si molar ratio. As metal oxide particles have lower surface area than polymeric silica structures, these results strongly suggest that the iron oxides opposed the silica structure collapse. The effect of sol pH was found to be less significant than the Fe/Si molar ratio in the formation of molecular sieve structures derived from iron oxide silica.