![]() ![]() To overcome this drawback of TiO 2, the formation of a heterojunction of CdS with TiO 2 in the form of core-shell nanostructure ( 2) is attractive due to the dual role played by the shell of TiO 2 over the CdS core. In photocatalysis, titanium dioxide (TiO 2) has stabile photoelectrical properties with a wide bandgap which can only be active in the UV region of the light spectrum. By combining all these strategies, there is still room to develop a new approach that can achieve enhanced activity and stability of CdS based photocatalysts without the use of noble metals. The use of noble metal loading on the heterojunction binary CdS-based photocatalysts is also an attractive approach that usually exhibits enhanced photocatalytic activity and stability but adds cost to the catalysts. Among all these strategies, the formation of a heterojunction of CdS with another semiconductor is a promising approach in terms of cost-effectiveness and efficient charge separation due to the built-in heterojunction leading to enhanced photocatalytic activity. Numerous efforts have been made to enhance the activity of CdS, including the use of noble metals as co-catalysts, doping of different elements in CdS and manipulating the morphological properties. ![]() Despite its fascinating photocatalytic properties, it exhibits a disappointing activity and stability toward the generation of H 2 due to the fast recombination of charge carriers and the photo-corrosion of CdS into elemental sulphur caused by the holes (h +) generated in the valence band during the photocatalytic reaction. 2.3 eV), is a promising catalyst for photocatalytic H 2 generation. Among many different semiconductor-based photocatalysts, cadmium sulfide (CdS), active in the visible range of the light spectrum due to narrow bandgap ( ca. However, there is still a need to find a suitable photocatalyst which will be highly active and stable. In the past few years, extensive efforts have been devoted to explore and investigate new approaches for the development of highly efficient and stable photocatalyst for H 2 generation from water. Photocatalytic hydrogen (H 2) generation from water, utilizing solar energy, is considered an appealing approach in the scientific community. To mitigate these serious issues, a renewable and environmentally friendly alternative energy transformation carrier is urgently needed. The burning of fossil fuels to meet the energy demands of modern society is not only increasing global warming exponentially but also leading to the depletion of conventional energy sources which may soon result in a severe energy crisis. The increased photocatalytic activity and stability of the 2 sample are attributed to the enhanced visible light absorption and efficient charge separation and transfer between the CdS and TiO 2 due to incorporation of graphene between the CdS core and TiO 2 shell, which was also confirmed by UV-vis, photoelectrochemical and valence band XPS measurements. The most optimized sample, i.e., 2 generated 1510 µmole g −1 h −1 of H 2 (apparent quantum efficiency (AQE) = 5.78%) from water under simulated solar light with air mass 1.5 global (AM 1.5G) condition which is ~2.7 times and ~2.2 time superior to pure TiO 2 and pure CdS respectively, along with a stable generation of H 2 during 40 h of continuous operation. The interlayer thickness of G between the CdS core and TiO 2 shell is optimized by varying the amount of graphene quantum dots (GQD) during the synthesis procedure. Aiming to achieve enhanced photocatalytic activity and stability toward the generation of H 2 from water, we have synthesized noble metal-free core-shell nanoparticles of graphene (G)-wrapped CdS and TiO 2 ( 2) by a facile hydrothermal method. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |