Study On Construction And Photocatalytic Performance Of Graphene Or Plasmonic Metal-Involved Composites

Graphene and plasmonic metal have attracted much attention from researchers,by the virtue of their unique physicochemical properties.They have shown a wider application prospect in photo catalysis.However,on one hand,low efficiency of interfacial charge carriers transfer and high probability of carriers recombination are two current bottlenecks for graphene-involved photo catalysts.One the other hand,how to take full advantage of plasmonic metal induced energy transfer scheme to optimize the efficiency of energy migration between components and to maximize the utilization of Plasmon energy,is a great challenge for plasmonic metal applying in photocatalysis.Besides,related investigations are still rather scarce.On the key principles of improving internal carriers separation in each component and perfecting interfaces to improve the matter(carriers)and energy transfer efficiency between different components,this thesis has carried out mainly the following aspects of study:A facile,mild and green proton-mediated electrostatic assembly-photoreduction two-stage approach has been developed,to synthesize ZnSn(OH)6/reduced graphene oxide(ZHS/RGO)composite with multilayered structure.Two components are assembled together via chemical bonds,that has been investigated and revealed.In our obtained fabrication,on one hand,ZHS/RGO/ZHS sandwich structure maximized the contact area of RGO.On the other hand,the conjugated bonds in the interface could serve as electronic transmission channels.Both of them col labor at ively improve interfacial carriers migration efficiency,achieving further enhancement of photocatalytic performance for semiconductor/graphene composite system.Combining the facet engineering and architectural engineering of semiconductor/graphene composite,we propose the model configuration of thin RGO layer completely covering the semiconductor with different facets exposed,to realize the vision of carriers in the bulk and surface of semiconductor dual-selectively-channel separation.Then,the prototype composite(BiV04/RGO)of totally close-coating BiVO4 with {010} and {110} facets exposed by a thin RGO layer.For the first time,the unique dual-selectivity-channel carrier separation mechanism in this model system is uncovered.Benefitting from the presence of the unique mechanism,carriers recombination both in the bulk and on the surface of BiVO4 are indeed inhibited,and the photoactivity is enhanced remarkably.We put forward a unique model architecture,in which plasmonic metal nanostructures deposited on the system of semiconductor with different facets exposed wrapped completely by thin RGO layer.BiVO4/RGO/Au photocatalyst with the designed configuration is fabricated successfully.In this fabrication,near-field electromagnetic energy transfer(NEET)is optimized,via synergistically regulating the thickness of RGO layer and fluorescent emission spectra of semiconductor,enhancing the utilization of Plasmon resonance energy.Moreover,this designed concept for optimizing and utilizing the local surface Plasmon resonance(LSPR)induced NEET mechanism,may provide a new model strategy to achieve high-efficiency energy migration between different components.A new unique ternary model architecture,in which plasmonic metal nanostructures embedded into up-conversion(UC)phosphor/semiconductor interfaces,is rationally proposed.And NaYF4:Yb3+,Er3+/Au/CdS model system is successfully fabricated.In the designed hybrid,plasmonic Au nanocrystals are embedded into the interface of core-shell structure.Such interfacial plasmonic Au with multiple mediator effects can elegantly establish NaYF4:Yb3+,Er3+/CdS interface,and compensate the shortcomings of the state-of-the-art UC-involved photocatalysts,that are high pumping threshold in photon power and low UC energy migration efficiency between UC phosphor and semiconductor component.UC photocatalysts are applied in photocatalytic bio-ethanol reforming to produce H2 reaction for the first time.Besides,our designed composite exhibits obvious bio-ethanol photoreforming activity under low-density NIR light irradiation.