Suitable preparation of Bi 2 S 3 nanorods – TiO 2 heterojunction semiconductors with improved photocatalytic hydrogen production from water/methanol decomposition

BACKGROUND Hydrogen, as a clean and renewable energy source has become very attractive due to the deterioration of the global environment. In this way photocatalytic water‐splitting for H 2 production using light energy in the presence of semiconductors capable of absorbing such irradiation has become a promising approach for generation of H 2 . The intensity of incident solar energy on the earth's surface is 1000 W m −2 and only 4% of the total solar energy corresponds to UV light (40 W m −2 ), but this could be sufficient for H 2 production from water splitting with very efficient semiconductors using the UV solar energy radiation. RESULTS The synthesis of Bi 2 S 3 –TiO 2 composites using TiO 2 sol–gel (3, 6 and 9 Bi 2 S 3 wt%) was performed by a solvothermal method and these materials were evaluated under UV light irradiation (254 nm, 2 W) for photocatalytic hydrogen production from a water/methanol solution. The optimal loading was obtained for the Bi 2 S 3 –TiO 2 composite at 6 wt% showing a production of 2460 µmol h −1 g −1 of hydrogen, increasing by a factor of 4 the production of bare TiO 2 at 564 µmol h −1 g −1 . The Bi 2 S 3 –TiO 2 composite presented good stability after three complete cycles of reaction, proving resistance to corrosion effects. CONCLUSION Bi 2 S 3 –TiO 2 presented a higher photocatalytic activity than bare TiO 2 for an optimal content of 6 wt% Bi 2 S 3 –TiO 2 .This improvement is attributed to enhanced absorption in the UV ‐Vis region of the Bi 2 S 3 –TiO 2 composite, and a higher transference of the charge carriers in the Bi 2 S 3 –TiO 2 heterojunctions with a hindered recombination e − /h + . © 2016 Society of Chemical Industry