HYDROGEN PRODUCTION PHOTOCATALICALLY BY Pd-SUPPORTED TiO2 IN THE PRESENCE OF AQUEOUS OXALIC ACID
Journal: Acta Chemica Malaysia (ACMY)
Author: Bin Guo, Ahmed H.A. Dabwanb, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata, Satoshi Kaneco
This is an open access journal distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
In this work palladium nanoparticles were supported on mixed mixture of 75 wt % anatase and 25 wt % rutile titanium oxide to create holes on the surface of titanium oxide and electrons on the surface of metal electrodes. The effects of different parameters were investigated namely, oxalic acid wt %, pH, Temperature, Irradiation time, and NaCl wt %. The formed particles were characterized by X-ray diffraction, high resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and diffuse reflectance UV-V is spectroscopy and nitrogen adsorption–desorption isotherms (BET). Hydrogen evolution was monitored by sampling at different intervals and measured using gas chromatography. Optimum conditions to obtain the highest hydrogen yields were; oxalic acid 2 wt % (2229 μmol g-1), pH 2.2 (2229 μmol g-1), Temperature 50 oC (2180 μmol g-1) and NaCl 1 wt % (3530 μmol g-1). No decreasing was observed when long term experiment was evaluated (154 hrs). This could be attributed to the fact when TiO2 is irradiated with light having a wavelength of 380 nm or less, a pair of electron holes is formed. Using the electrons, Pd ions are reduced and precipitated on TiO2. At this time, if Pd is reduced and precipitated on TiO2, it is considered that the electrons photogenerated by TiO2 move onto Pd, suppress the recombination of electrons and holes, and promote the hydrogen production reaction in other words photogeneration can proceed as long as there is irradiation.