A new lanthanum(III) complex, [La(MO)3(DMF)3(H2O)2] (MO = methyl orange), and La2O2SO4 nanoparticles; electrocatalytic activity for adsorption/desorption/evolution of hydrogen

A new lanthanum(III) complex, [La(MO)3(DMF)3(H2O)2] (MO− = methyl orange), was synthesized by the reaction of methyl orange and lanthanum(III) nitrate hexahydrate in the aqueous solution. The complex was characterized by elemental analysis, FT-IR, UV–Vis, and single-crystal X-ray diffraction. Then the lanthanum oxysulfate nanoparticles (La2O2SO4) were prepared by calcination of [La(MO)3(DMF)3(H2O)2] as a new precursor. The nanoparticles were characterized by FT-IR, X-ray diffraction analysis (XRD), and field emission scanning electron microscopy (FE-SEM). Finally, the hydrogen adsorption/desorption properties of the La(III) complex and La2O2SO4 nanoparticles were investigated at a glassy carbon electrode (GCE) in H2SO4 by cyclic voltammetry (CV). The voltammograms showed a pair of peaks corresponding to the adsorption/desorption of hydrogen for both compounds. Also, the electrocatalytic activity of both compounds for the hydrogen adsorption and hydrogen evolution reaction (HER) was investigated by linear sweep voltammetry (LSV).

Graphical abstractA new lanthanum(III) complex, [La(MO)3(DMF)3(H2O)2] (MO− = methyl orange), was synthesized and characterized. The lanthanum oxysulfate nanoparticles (La2O2SO4) were prepared by calcination of [La(MO)3(DMF)3(H2O)2] as a new precursor. The electrocatalytic activity of both compounds for hydrogen adsorption/desorption/evolution reactions of H2 was investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide