Three dimensional rosette-rod TiO2/Bi2S3 heterojunction for enhanced photoelectrochemical water splitting

Abstract

Abstract In this work, we have fabricated a three-dimensional double layered rosette-rod TiO2 heterojunction with Bi2S3 using two-step hydrothermal method and solvothermal route. A seed layer approach is also used to assist uniform distribution of Bi2S3 and to form a perfect heterojunction between TiO2 and Bi2S3. Morphologically studies reveal that the double layered rosette-rod TiO2 (RT) architecture consists of two main parts one dimensional TiO2 nanorod arrays present at the bottom for direct transfer of photo induced electron and hole pairs, while the upper three-dimensional nano rosette consisting of small TiO2 nanorods as building units to enhance the surface area and light harvesting efficiency. Morphology of Bi2S3 also found to be affected relatively by the growth duration and the presence of seed layer. Photoelectrochemical performance at 1.23 V RHE bias-potential under 100 mW cm−2 solar light illumination shows that synthesized RT_Bi2S3 photoanode demonstrates the highest photocurrent density of 3.98 mA cm−2, which is practically 10 times higher than RT (0.39 mA cm−2) and 5.5 times higher than RT_ Bi2S3 photoanode without the seed layer (0.74 mA cm−2). It is remarkable to mention that photocurrent density of RT_ Bi2S3 photoanode to the best of our knowledge is superior to all the TiO2 and Bi2S3 based photoanodes used in photoelectrochemical cells reported in the literature.