Photocatalytic hydrogen production from methanol over Nd/TiO2

Abstract

Nd modified TiO2 photocatalysts containing 0.15-1.5 wt.% of Nd (wt.% Nd determined by XRF) as well as parent TiO2 were investigated for the photocatalytic oxidation of CH3OH. The photocatalysts were prepared by the common sol-gel method followed by thermal treatment. The textural, structural and electronic properties of all synthesized photocatalysts were characterized by nitrogen physisorption, powder X-ray diffraction, X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, Raman spectrometry, DR UV-vis spectroscopy, electron paramagnetic resonance spectroscopy and photo-electrochemical measurements. It was revealed that all materials show comparable band gap energy and phase composition. However, the addition of different amounts of Nd in the range of 0.15-1.5 wt.% significantly affected the TiO2 crystallite size, the specific surface area, the amount of surface 0 species and subsequently also the photocurrent response. The positive role of neodymium was proved at its very low loading, i.e. for Nd/TiO2 with 0.15 wt.% Nd which exhibited the highest photocatalytic activity. The photocatalytic activity was promoted by both increasing crystallite size of TiO2 and decreasing amount of surface O species.