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Iron-cobalt phosphomolybdate (FeCoPM ) nanoparticles, which are highly efficient catalytic materials for the oxygen evolution reaction (OER), were fabricated through a coprecipitation route. Compared with iron-cobalt hydroxide and state-of-the-art RuO electrocatalysts, the as-prepared FeCoPM sample exhibited robust OER catalytic activity with a low overpotential of 258 mV at a current density of 10 mA cm and a small Tafel slope of 33 mV dec . Moreover, the as-synthesized sample presented preferable stability and after 10 h at 1.52 V the current density degraded by merely 8.3 %. This is ascribed to the high electrochemical stability and small porous structure of FeCoPM , which provide effective electron transmission and improve the catalytic performance for OER in alkaline media.

Fluorescent carbon dots (CDs) were successfully synthesized via pyrolysis of Setcreasea purpurea boom, providing a simple and convenient method for the preparation of CDs without using toxic or expensive materials.

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An effective adsorbent for methyl violet (MV), chromium phosphovanadate (named as Cr-PV) nanomaterials, was prepared by a simple coprecipitation strategy. The microstructure and morphology of as-synthesized Cr-PV were characterized by SEM, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR), respectively, which was confirmed as nanosheet shapes. The adsorption behavior for MV from aqueous solutions was systematically investigated. The kinetic and equilibrium results indicate that the adsorption process follows pseudo-second-order kinetic model and Langmuir isotherm, respectively. Compared with PV and commercially available activated carbon, Cr-PV has preferable adsorption property to MV. The maximum adsorption capacity can reach 123.81 mg g −1 at room temperature. The thermodynamic parameters such as Gibbs free energy (ΔG ο), enthalpy (ΔH ο), and entropy change (ΔS ο) show that the adsorption of MV is an endothermic and spontaneous process. Moreover, the adsorptive behavior between Cr-PV and MV is monolayer adsorption and electrostatic interaction mechanism. Cr-PV, as a promising adsorbent with high adsorption capacity and fast adsorption rate, shows great potential for the removal of MV from wastewater.