Photocatalytic acetic acid decomposition leading to the production of hydrocarbons and hydrogen on Fe-modified TiO2

A photocatalytic generation of useful hydrocarbons and hydrogen from acetic acid under N2 atmosphere is presented. The photocatalysts were prepared from a crude TiO2 modified with Fe(NO3)3 and calcinated at the temperatures of 400–600 °C in argon atmosphere. The main gaseous products of CH3COOH decomposition were CH4 and CO2. Moreover, ethane, propane and hydrogen were also detected. The most active photocatalyst towards CH4 generation was TiO2 containing 20 wt.% of Fe calcinated at 500 °C. The optimum loading of this photocatalyst was 1 g/dm3. After 5 h of the process the amount of CH4, CO2, C2H6, C3H8 and H2 evolved was 0.458, 0.450, 0.025, 0.003 and 0.013 mmol, respectively. An increase of CH3COOH concentration from 0.01 to 1 mol/dm3 resulted in an increase of methane production. A further increase of CH3COOH concentration up to 10 mol/dm3 led to a decrease of the process efficiency. The stability of the prepared photocatalysts against photocorrosion was very high. The amount of dissolved Fe did not exceed 0.17 wt.% of the total Fe present in a catalyst sample.