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In this research paper, the thermal behaviour of the mixed valence iron oxides Fe3(PO4)2(OH)2 is presented in both air and vacuum atmosphere. The structure, morphology and the magnetic properties of the iron phosphates samples obtained at selected temperatures were carefully investigated. The electrocatalytic properties of synthetic barbosalite Fe3(PO4)2(OH)2 materials for the oxygen and hydrogen evolution reactions (OER and HER) were investigated in a wide pH range, using graphite electrodes modified with different compositions containing the catalyst. The best results were obtained for the compositions with 6 mg barbosalite. During the HER experiments, overpotentials of − 300 and − 350 mV were observed at the current density of − 10 mA cm−2 in strong alkaline and in strong acidic media, respectively. During the OER studies performed in strong acidic solution and in neutral environment, overpotentials of 320 and 690 mV were obtained at the current density of 10 mA cm−2. These findings complement the existing scientific literature relevant to the water splitting domain. Furthermore, the visible light absorption ability of synthetic Fe2+Fe3+2(PO4)2(OH)2 materials was also evaluated. [ABSTRACT FROM AUTHOR]

Ag-doped LaMnO3 nanoparticles have been synthesized through sol–gel process using citric acid as a chelating agent. Silver effect on physicochemical properties was studied. The physicochemical properties and electrical performance of the obtained materials were also investigated, using thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. Thermogravimetric analysis shows that for the studied materials a decomposition stage between 3.7% and 4.1% can be observed, and mass increases from the LMN-Ag1 to the LMN-Ag3 sample. Also, in all those three situations an endothermic process with a maximum around 600 °C is observed. The diffractograms of the perovskite materials showed single-phase crystalline with high purity and rhombohedral structure with R-3c space group. The electrical measurements show that the conductivity spectrum is formed by both the static component σDC corresponding to the low frequencies and the component σAC corresponding to high frequencies. The values of σDC of samples are significantly influenced by the silver ions concentration. [ABSTRACT FROM AUTHOR]