Mohammad Derakhshani, Saeed Rastegari, Ali Ghaffarinejad,
Volume 21, Issue 2 (6-2024)
Abstract
In this research, a nickel-tungsten coating as a catalyst for hydrogen evolution reaction (HER) with different current densities was synthesized and the resulting electrocatalytic properties and morphology were assessed. Linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry in 1 M NaOH were used to evaluate the electrocatalytic activity for HER. By increasing the current density of electrodeposition up to 500 mA/cm2, a columnar morphology was observed. The cyclic voltammetry test (CV) revealed that when the plating current density increases, Cdl has increased from 248 to 1310 µF/cm2 and the active surface area increases 5 times. The results showed that by modifying the coating morphology, the current density of the hydrogen evolution increased up to two times.
Yofentina Iriani, Novia Puspita, Dianisa Sandi, Fahru Nurosyid, Risa Suryana, Didier Fasquelle,
Volume 21, Issue 4 (12-2024)
Abstract
In this research, Lanthanum (La)-doped Strontium Titanate (STO) with the formula of Sr1-xLaxTiO3 (LSTO; x=0, 0.03, 0.05, and 0.07) powders have been successfully fabricated by co-precipitation route. The impacts of La3+ on the structural, microstructure, band-gap, and photocatalytic activity for the degradation of organic pollutants, in this case, methylene blue, under UV exposure, were reported in detail. The formation of undoped and La-doped STO samples with cubic perovskite structures was confirmed by X-ray Diffraction (XRD) results. The presence of La doping affected the microstructure morphology by producing LSTO powders with a larger specific surface area. Besides, the UV absorption of the LSTO powders was enhanced due to the narrowed band gap caused by La3+ dopants. Accordingly, an improvement in photocatalytic activity applied for the photodegradation of methylene blue solution was exhibited by the LSTO samples.
