Sparkling Synergy: Enhancing Hydrogen Evolution with a Mesoporous CoP/FeP Interface

The reaction kinetics is predominantly determined by the surface and interface engineering of electrocatalysts. Herein, we demonstrate the growth of cobalt monophosphide and iron monophosphide (CoP/FeP) with an effective solid interface. The surface of CoP/FeP is mesoporous, which is obtained by phosphidizing mesoporous CoFe2O4. The CoP/FeP electrode exhibits substantially superior hydrogen evolution reaction (HER) performance compared to CoP and FeP. The overpotentials (η) required to generate 10 mA cm-2 are determined to be around 98 mVRHE (CoP/FeP), 220 mVRHE (FeP), and 265 mVRHE (CoP) in an acidic electrolyte. The exchange current density and Tafel slopes suggest that CoP/FeP has better redox properties and kinetic abilities compared to FeP and CoP. Furthermore, the CoP/FeP electrode exhibits reduced electrochemical impedance and superior surface charge transport characteristics in comparison to both the CoP and FeP electrodes. In addition to having a greater number of catalytically active sites, the turnover frequency of CoP/FeP is approximately 2 and 5 times higher than that of FeP and CoP, respectively. The CoP/FeP electrode maintains a consistent current density of around 25 mA cm-2 for a continuous period of 24 h during the HER, attesting to the excellent durability of the CoP/FeP electrode. In addition, a relationship between differential hydrogen adsorption energy (ΔEH), the corresponding Gibbs free energy change (ΔGH), and the hydrogen coverage on distinct surfaces, namely, CoP, FeP, and CoP/FeP, is established. The calculation findings show that the CoP/FeP surface, which is predominantly exposed with CoP, exhibits the highest catalytic potential for the HER. The estimation of the specific HER activity of the electrodes, normalized to the electrochemically active surface area, corroborates the calculation findings.

A controllable one-pot hydrothermal synthesis of spherical cobalt ferrite nanoparticles: synthesis, characterization, and optical properties

We herein report the controllable synthesis of spherical cobalt ferrite nanoparticles with average crystallite size in the range of 3.6–12.9 nm using a facile, eco-friendly, hydrothermal method. The hydrothermal treatment was carried out by utilizing cobalt nitrate, ferric nitrate, and ammonium hydroxide in the presence and absence of Arabic gum as a surfactant agent. The purity and crystallinity of the products were tuned by varying reaction conditions such as reaction time (0.5–8 h), reaction temperature (120–180 °C), percentage of ethylene glycol (0–100% (v/v)), pH (8–9.6), and amount of Arabic gum (0–2 g). We characterized the prepared products using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy analysis (EDS), selected area electron diffraction (SAED) patterns, and UV-visible diffuse reflectance spectra (DRS). The optimal hydrothermal treatment was performed at 180 °C and pH 9.6 for 4 h in aqueous media. The results also revealed that the as-prepared spinel cobalt ferrite nanoparticles have an estimated optical band gap energy in the range of ca. 1.6–1.9 eV, indicating the semiconducting characteristics of the products.

A controllable synthesis of spherical cobalt ferrite nanoparticles with average crystallite size in the range of 3.6–12.9 nm using a facile, eco-friendly, hydrothermal method.

Facile synthesis of yolk–shell structured ZnFe2O4 microspheres for enhanced electrocatalytic oxygen evolution reaction

Yolk–shell structured ZnFe₂O₄ microspheres with excellent OER performance are synthesized via a facile solvothermal method and annealing treatment.

Synthesis of size-tuneable β-FeOOH nanoellipsoids and a study of their morphological and compositional changes by reduction

Synthesis of finely size-tuned β-FeOOH nanoellipsoids which could be used as precursors to form anisotropic iron oxide nanoparticles by reduction.

Surface modified multifunctional ZnFe2O4 nanoparticles for hydrophobic and hydrophilic anti-cancer drug molecule loading

By appropriate surface functionalization, multifunctional ZnFe₂O₄ nanoparticles exhibiting RT ferromagnetism and green emission has been loaded with a hydrophobic drug molecule-curcumin and a hydrophilic drug molecule-daunorubicin.

Irreversible phase transition in BiVO4 nanostructures synthesized by a polyol method and enhancement in photo degradation of methylene blue

Structure and bonding in metal oxides has been studied extensively using Raman vibrational spectroscopy and is found to provide complementary information to the crystallographic observations.

Magnetic stability against calcining of microwave-synthesized CoFe2O4 nanoparticles

The magnetization of microwave-synthesized CoFe₂O₄ nanoparticles, after the stringent thermal treatment that would be necessary to prepare hybrid ferromagnetic–YBCO films, is preserved.

Varied forms of lamellar [Sn3Se7]n2n− anion: the competitive and synergistic structure-directing effects of metal–amine complex and imidazolium cations

Presented are the varied forms of a lamellar [Sn₃Se₇]_n²ⁿ⁻ anion produced by the competitive and synergistic structure-directing effects of a metal–amine complex and imidazolium cations.

V-containing ZrO2 inorganic yellow nano-pigments

Inorganic yellow nano-pigments based on monoclinic vanadium–zirconia solid solutions for digital decoration prepared by a polyol approach.

Synthesis of water well-dispersed PEGylated iron oxide nanoparticles for MR/optical lymph node imaging

We reported the synthesis of highly water-stable iron oxide nanoparticles by a simple one-pot reaction. Non-toxic polyethylene glycol MW 600 (PEG) acted as a solvent, capping agent and reducing agent in the synthesis of iron oxide nanoparticles. As a result of the synthesis, PEGylated small-size (4.2 ± 0.39 nm average diameter and 7.2 ± 1.9 nm hydrodynamic sizes measuring by DLS) iron oxide nanoparticles (USPIO) were obtained, which show great colloidal stability in water and tolerate high salt concentration (0.75 M sodium chloride) and a wide pH range of 4 to 12. Oxidation of PEG was observed during the synthesis of iron oxide nanoparticles, which makes USPIO easy to functionalize with other molecules. Functionalization of the USPIO surface with fluorescein isothiocyanate (FITC) was conducted for investigating the possibility for multimodal imaging. Also the cytotoxicity test and lymph node imaging were performed by using the FITC labelled USPIO (FITC@USPIO). According to these results, the stable water dispersed USPIO and FITC@USPIO are expected to apply for multimodal in vivo imaging.