| Semiconductor heterojunction（n-n heterojunction,p-n heterojunction）has a special energy band structure,which can effectively reduce eletron-hole recombination,thus it has become a hot spot in the study of photocatalytic hydrogen production.Cadmium sulfide is commonly used as one of the components of the heterojunction because it can satisfy all conditions for photocatalytic water splitting into hydrogen,which has attracted much attention.One-dimensional（1D）nanomaterials can effectively transport carriers,and two-dimensional（2D）nanomaterials have high surface area.Fabrication of energy band-matched 1D/2D heterojunction can integrate the advantages of both dimension and heterojunction.However,due to the differences in the growth model for differently dimensional nanounits,the synthesis of multi-dimensional nanostructured materials is still a great challenge.Considering the above facts,in this dissertation,multi-dimensional and multi-element CdS-based composite photocatalysts were synthesized through two new strategies,using 1D CdS nanowires as support.The main contents include:（1）We have synthesized CdS NWs/CdIn2S4 NSs 1D/2D heterojunctions through the confinement effect of CdS NWs and regulating action of ethylene glycol complexing agent on the release of Cd2+ ions in CdS.Products were characterized by XRD,FE-SEM,TEM,BET,XPS,ICP,UV vis-visble diffuse reflectance spectra,and PL indetail.The obtained CdS NWs/CdIn2S4 NSs heterojunctions showed much higher visible-light-responding photocatalytic activity for water splitting into hydrogen compared with single components.CdS NWs/CdIn2S4 NSs were further fabricated into photoelectrode and achieved a considerable photocurrent density of 4.8 mA cm-2 at an applied voltage of 1 V vs.reversible hydrogen electrode（RHE）,which is among the best records for CdS-based photoelectrochemical（PEC）cell.The present work not only provided a new strategy for constructing1D/2D heterojunctions but also developed highly efficient catalysts for energy conversion.（2）CuInS2/CdS 1D superstructures were successfully synthesized at200 ℃ for 50 min through ion exchange and catalytic growth route,using CdS nanowires,CuCl2×2H2O,InCl3×4H2O and L-cysteine as raw materials,ethylene glycol as solvent.The products were characterized by XRD,FE-SEM,TEM,XPS and ICP in detail.The formation mechanism of the products was systematically studied through time-dependent composition analyses and electron microscopy observations.This study provides a significant reference for the design of multidimensional and multielement heterojunction materials. |
