Photocatalytic hydrogen production from methanol over Nd/TiO₂
M. Edelmannová^a, Kuan Yu Lin^b, Jeffrey Chi-Sheng Wu^b, Ivana Troppová^a, Libor Čapek^c, Kamila Kočí^a

^aInstitute of Environmental Technology, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava, 70833, Czech republic,

^bNational Taiwan University, Catalyst Laboratory of the National Taiwan University, Taipei, 10617, Taiwan

^cFaculty of Chemical Technology, University of Pardubice, Studentská 95, 532 10 Pardubice, Czech Republic.
e-mail: miroslava.edelmannova@vsb.cz

Abstract

Economic development causes an increase in energy consumption and a conbsequent increase environmental pollution. CO₂ emissions have increased by 1.9 % per year over the last three decades, which is closely related to the increased use of fossil fuels. Addressing the challenge of increasing energy consumption in conjunction with environmental threats. It is a challenge for the whole of society to solve the issue of increasing energy consumption in conjunction with environmental threats. Photocatalytic reduction of CO₂ is one of the interesting ecological methods of reducing CO₂ emissions in the atmosphere, using sunlight as the radiation source.

In this work, copper-doped TiO₂-based photocatalysts (1, 3 and 5 wt.% CuO) were investigated for the photocatalytic reduction of CO₂ and the experiments were carried out in two reactions (liquid and gaseous phases) with the addition of hydrogen. In the liquid phase reaction, the highest yields of CH₄ were found in the presence of 5 wt.% CuO/TiO₂ and pure TiO₂. The activity of photocatalysts was mainly influenced by two factors: the availability of active sites (S_BET) and the output work needed to release the electron from the surface (work function). The lowest energy for electron release at the wavelength of 254 nm and the highest specific surface area (119 and 66 m²/g) was found for TiO₂ and 5 wt.% CuO/TiO₂. In the gas phase reaction, CH₄ and CO yields decreased in the order: TiO₂ > 3 wt.% CuO / TiO₂ > 5 wt.% CuO / TiO₂ > 1 wt.% CuO / TiO₂. Conducting the experiment in different phases does not seem to change the mechanism of photocatalytic reduction of CO₂, but the location of the photocatalyst in the different phases can accelerate the different reaction pathways.