Ferrihydrite gels derived in the Fe(NO3)3·9H2O–C2H5OH–CH3CHCH2O ternary system

Talantsev, E. F.; Pantoya, Michelle L.; Camagong, Cristina T.; Lahlouh, Bashar; Nicolich, Steven; Gangopadhyay, Shubhra

doi:10.1016/j.jnoncrysol.2005.03.038

Cited by 4 publications

(1 citation statement)

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“…Propylene oxide was successfully used as proton acceptor in the present authors earlier works [9,10], following the experimental procedure proposed by Gash, Simpson, Tillotson and coworkers [11][12][13][14]. This procedure was also followed by other authors, either to describe the chemical mechanisms involved or to investigate the performance of the obtained materials as oxidants for pyrotechnic mixtures [15][16][17][18][19]. However, propylene oxide is harmful to operators (toxic, very volatile and highly carcinogenic) and leads to the formation of ramified alcohols that are difficult to remove in the drying stage [9,10,14,20].…”

Section: Introductionmentioning

confidence: 95%

Sol‐gel synthesis and washing of amorphous g‐FeO(OH) xerogels

Durães¹,

Benedini

Costa

et al. 2012

Materialwissenschaft Werkst

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Iron(III) oxyhydroxide xerogels were prepared by the sol-gel technology including a washing step for removal of a salt by-product. The synthesis involved an iron(III) nitrate nonahydrate as precursor, ethanol as solvent and ammonium hydroxide as gelation agent, following the procedure of an earlier work. As this chemical route originates ammonium nitrate as a by-product dispersed in the iron oxyhydroxide matrix, the removal of this salt by washing the gel before the drying stage is here studied. Two solvents were tested, namely water and ethanol, being the best washing efficiency (95%) achieved with water and two washing batches. Comparing the xerogels obtained without and with the washing step, the later only contained an insignificant amount of ammonium nitrate salt, as confirmed by Elemental Analysis, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The iron phase in the washed xerogels was found to be g-FeO(OH), according to FTIR and Mössbauer spectroscopy results, and in consonance with the prevailing iron phase in the unwashed xerogels. The washed xerogels are amorphous and formed by large clusters of well connected nanocrystallites of iron oxyhydroxide. The washing step enhanced the clearing of mesopores, originating materials with a specific surface area of l 250 m 2 /g, 60 times higher than for unwashed xerogels.Keywords: sol-gel / g-FeO(OH) / nanostructured materials / amorphous solids / washing / Schlüsselwörter: Sol-Gel / g-FeO(OH) / nanostrukturierte Materialien / amorpher Festkörper / Aufbereitung /

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Section: Introductionmentioning

confidence: 95%

Sol‐gel synthesis and washing of amorphous g‐FeO(OH) xerogels

Durães¹,

Benedini

Costa

et al. 2012

Materialwissenschaft Werkst

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Electro‐induced Crystallization Over Amorphous Indium Hydroxide Gels Toward Ampere‐Level Current Density Formate Electrosynthesis

Zhao,

Huang,

Liu

et al. 2024

Adv Funct Materials

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Electrochemical CO2 reduction reaction (CO2RR) provides a promising way for producing value‐added fuels and chemicals via renewable electricity. However, the dynamic reconstruction of electrocatalysts of atomic active sites hinders in‐depth understanding of catalytic mechanism and further industrial application, especially under ampere‐level current density conditions. In this work, electro‐induced crystallization is reported over an amorphous Indium hydroxide gel (In gel) catalyst, which generates active sites for efficient and selective CO2RR. Molecular dynamic calculation reveals the crystallization process can maintain amorphous In‐OH species on the surface while generating crystallized metallic In under electroreduction condition; structural characterizations prove that the derived partially crystallized In gel is stable consisting of amorphous/crystalline interface, even biased at a high polarization potential of −4 V versus reversible hydrogen electrode. The resultant partially crystalized In gel exhibits a highly selective CO2RR performance toward formate under an ampere‐level current density up to 1200 mA cm−2 simultaneously with 91.89% Faradaic efficiency, which can motivate a high formate generation rate of 20.55 mmol h−1 cm−2. The operando Raman spectroscopic and density functional theoretic results demonstrate the optimized adsorption of *HCOO intermediate for the enhanced formate activity and selectivity over the partially crystallized In gel.

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