Enhanced Acidic Hydrogen Evolution on TiO2-Doped Gadolinium Electrocatalysts

Gadolinium-doped TiO2 NPs, namely TiO2-Gd1.0 and TiO2-Gd6.0 have been synthesized using two different atomic concentrations of gadolinium(III) nitrate hexahydrate in presence of titanium(IV) tert-butoxide as a titanium precursor and dimethyl sulfoxide as a solvent. The structure and morphology of these NPs have been characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The two synthesized TiO2-Gd1.0 and TiO2-Gd6.0 were tested as electrocatalysts for hydrogen evolution reaction (HER) in an acidic electrolyte (0.5 M H2SO4) based on linear sweep voltammetry (LSV) measurements. LSV data were fitted to Tafel equation and the various electrochemical parameters describing the HER kinetics were evaluated and discussed. Results demonstrate that the kinetics of the HER on the surface of TiO2 NPs significantly enhanced upon doping it with Gd3+, proportionally to the atomic concentration of the Gd3+ cations in the TiO2 NPs.