Modification and characterization of strontium titanate for photocatalytic water splitting

Abstract

Energy and environmental problems are main factors that affect the sustainability of life. Researches for finding environmental friendly alternative energy with high efficiency have been done until now. Hydrogen is an alternative energy that is renewable and clean. Photocatalytic water splitting is one of many methods to produce hydrogen. $SrTiO_3$ is used as photocatalyst candidate because of its photosensitivity can be extended to visible light region. In this research, $SrTiO_3$ was doped with carbon to increase the photosensitivity to visible light area. The doped of carbon caused change in photoresponse of photocatalyst sytem to visible light region. Hence, the photocatalyst could harvest more light energy to generate more hydrogen. $SrTiO_3$ was also doped with lanthanum, and nano meter size of SiC was dispersed in photocatalyst system to form composite photocatalyst system. Since SiC has small band gap, it is able to absorb the light energy from visible light region. The performance of composite system showed significant enhancement with the existence of SiC in $SrTiO_3$ lanthanum doped particles. $SrTiO_3$ was also tested for Z-scheme photocatalytic water splitting mechanism which is also called two-photon process. $SrTiO_3$ was doped with rhodium to enhance the evolution of hydrogen and coupled with $WO_3$ to produce oxygen. The two photocatalysts were attached to each other, and redox mediator solution was used to serve the transfer of electrons between two photocatalysts. The increasing of hydrogen generated was found by the increasing of rhodium doped in $SrTiO_3$. The apparent photocatalytic activity (APA) from each sample of photocatalyst was calculated, and compared with the APA result from other researches.