Suitable preparation of Bi2S3 nanorods -TiO2 heterojunction semiconductors with improved photocatalytic hydrogen production from water/methanol decomposition

BACKGROUNDHydrogen, 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. RESULTSThe synthesis of Bi2S3-TiO2 composites using TiO2 sol-gel (3, 6 and 9 Bi2S3 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 Bi2S3-TiO2 composite at 6 wt% showing a production of 2460 mu mol h(-1) g(-1) of hydrogen, increasing by a factor of 4 the production of bare TiO2 at 564 mu mol h(-1) g(-1). The Bi2S3-TiO2 composite presented good stability after three complete cycles of reaction, proving resistance to corrosion effects. CONCLUSIONBi2S3-TiO2 presented a higher photocatalytic activity than bare TiO2 for an optimal content of 6 wt% Bi2S3-TiO2 .This improvement is attributed to enhanced absorption in the UV-Vis region of the Bi2S3-TiO2 composite, and a higher transference of the charge carriers in the Bi2S3-TiO2 heterojunctions with a hindered recombination e(-)/h(+). (c) 2016 Society of Chemical Industry