Nahit AKTAŞ

Article | 2022 | International Journal of Hydrogen Energy47 ( 49 )

The wetness impregnation method was used to synthesize 0.1 CdSe/TiO2 photocatalysts with different atomic molar ratios (90-10, 70-30, 50-50, and 30-70). These catalysts were characterized by XRD, SEM-EDX and mapping, TEM-EDS, UV-VIS spectroscopy, fluorescence spectroscopy, XPS, TPR, TPO, and TPD analyses. Cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) analyses were performed to examine the photocatalytic activity for photocatalytic fuel cells (PFCs) in glucose solution in the dark and under UV illumination. The characterization analyses revealed that anatase TiO2 formed the catalyst . . . and electronic structure and surface properties changed when doped with metal. The photocatalytic glucose electrooxidation (PGE) results demonstrate that the 0.1 CdSe(50-50)/TiO2 catalyst has higher photocatalytic activity, stability, and resistance than other catalysts both in the dark (2.71 mA cm(-2)) and under UV illumination (7.20 mA cm(-2)). These results offer a promising new type of photocatalyst for PFC applications. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved More less

Hilal DEMİR KIVRAK | Nahit AKTAŞ

Article | 2022 | International Journal of Hydrogen Energy47 ( 83 )

Herein, carbon nanotube (CNT)-supported Ga@PdAgCo catalysts were synthesized by sodium borohydride (SBH) sequential reduction method. These catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-mass spectrometry (ICP-MS). Characterization results revealed that these catalysts were succesfully preared at desired loading and atomic ratios. From the XRD pattern, the crystallite size of 0.5 Ga@PdAgCo(80:10:10)/CNT catalysts was found as 6.95 nm by utilizing the Scherrer equation. From TEM measurements, the average particle s . . .izes of Pd/CNT, PdAgCo(80:10:10)/CNT, and 0.5 Ga@PdAgCo(80:10:10)/CNT catalysts were found to be 54 nm, 25 nm, and 7 nm, respectively. It is clear that particle sizes obtained from TEM and XRD were close to eachother. Electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), and cyclic voltammetry (CV) measurements were realized to examine the formic acid and ethylene glycol electrooxidation performances of catalysts. 0.5 Ga@PdAgCo(80:10:10/CNT) and 7 Ga@PdAgCo(80:10:10/CNT) catalysts had the best specific activity and mass activity as 3.37 mA/cm(2) (297.61 mA/mg Pd) and 4.95 mA/cm(2) (462.59 mA/mg Pd) for ethylene glycol and formic acid electrooxidation, respectively. In addition, EIS results showed that Ga@PdAgCo(80:10:10/CNT) catalyst had a faster electron transfer rate via low charge transfer resistance. As a result, 0.5 Ga@PdAgCo(80:10:10/CNT) catalyst is a promising new anode catalyst for direct ethylene glycol fuel cells. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved More less