Hybrid Nanostructures Of Metal Chalcogenides And Noble Metals:Synthesis And Catalytic Studies

Metal chalcogenide and noble metal nanomaterials show important applications in photocatalysis,solar cells and catalysis.Their catalytic properties are highly affected by their size,morphology,composition and other characteristics.Besides,the further integration of these nanomaterials into hybrid nanostructures offers even unique or remarkable improved properties.Therefore,achieving the delicate,independent,flexible modulation of the microstructures,components and interfaces in hybrid nanostructures is critical for the development of novel catalytic nanometerials as well as the comprehensive enhanecement of catalytic performance.In this dissertation,the metal chalcogenide?metal chalcogenide,metal chalcogenide?noble metal,and bimetallic hybrid nanostructures are presented as the subjects,while the improvement of catalytic performance is set as the objective.We further develop the synthetic strategy of the innovative hybrid nanostructures to achieve the control of their structures,which is essential for the exploring the structure-actitvity relationship of the nanomaterials.One dimensional heterostructures are promising candidates in the field of solar energy conversion because of their fast charge separation and the direct carrier transportation.However,it's still challenging to achieve the arbitrary size and composition of the heterostructures due to the complextities of different phases and components.We develop a seeded growth method for the controlled synthesis of a series of one-dimensional Cu_1.94S?Zn S heteronanorods and heteronanowires,which exhibit different sizes,morphologies and uniform structures.This facile,high reproducible strategy is suitable for large-scale synthesis,assembly and flexible photovoltaic application of one-dimensional heteronanostructures.Most of the metal sulfides suffer from low visible-light-driven photocatalytic efficiency owing to the large carrier recombination.Assisted with the seeded growth,we have successfully fabricated the uniform,high quality Cu_1.94S?Zn_xCd_1-xS heteronanorods with the continuous bandgap adjustment.Further deposition of Pt cocatalyst forms Cu_1.94S?Zn_xCd_1-xS/Pt hybrid nanostructures.The integrated design and simultaneous control over morphology,composition,band gaps and heterointerfaces lead to the high photoactivity under visible light irradiation.Additionally,we propose the spatial charge separation mechanism of these hybrid nanostructures and how the component influences band gap alignment.This work provides an avenue for the design and exploiting innovative hybrid nanomaterials in photocatalysis.The hybrid/bimetallic nanostructures composed of noble metals and transition metals have been intensely utilized in catalysis.Nevertheless,there's still an urgent need to improving the efficacy of precious metal as well as promote the catalytic activity and selectivity.In this work,we present a facile one-pot synthesis of Ru Cu nanocages and core-shell Ru@Cu nanocrystals by a modified galvanic replacement reaction.By exploiting the structural evolution of these nanostructures,we postulate the formation mechanism of these bimetallic nanostructures.Discussions about the relationship between the microstructures of bimetallic nanocrystals and their catalytic performance are also provided.We hope this work can open up opportunities for low-cost,highly activebimetallic nanocatalysts with efficient noble metal utilization.