| Nowadays,the rapid development of industrialization is resulting the fossil energy resource that human beings rely on is decreasing and the environment destructing more seriously caused by exploitation.The depletion of fossil energy and the aggravation of environmental destruction are two difficult problems to be solved in the 21st century.Utilizing semiconductor photocatalytic technology to convert solar energy into chemical fuel resource through photocatalyst is of great significance to solve the global energy shortage and environmental problems.Cadmium sulfide（CdS）,a kind of photocatalyst with visible light response and is one of the most promising materials in the field of photocatalysis,due to its excellent optical and electrical properties.while pure CdS has some defects,such as photogenerated carriers are easy to recombine,weak light absorption ability and photocorrosion.Which greatly limits its research and practical application in the field of photocatalysis.In this thesis,the methods of controlling morphology,constructing heterojunctions and loading cocatalysts were adopted respectively to fabricate a series of CdS-based photocatalysts in order to deal with above shortcomings.The properties such as morphology,structure and photoelectric performance of the as-prepared catalysts were analyzed by multiple characterization techniques and the relationship between structures and catalytic properties were investigated,the mechanisms of photocatalytic enhancement of the catalyst were explored.The main research contents are as follows:（1）The non-noble mental co-catalyst Mo2C/CdS hollow core-shell composite with CdMoO4 transition layer is fabricated via a continuous annealing-hydrothermal method.There,the as-prepared Mo2C/CdMoO4/CdS composite exhibits a remarkable photocatalytic HER enhancement of about～50 folds than that of pure CdS.Which can be mainly ascribed to that,the Mo2C with lower Fermi level can capture-diffuse the photoelectron to water quickly and decrease the photocorrosion,the CdMoO4transition layer canpromote the charge carriers transport,the 3D hollow structure can improve the HER active sites,solar efficiency and structure stability,and can be proved by the electrochemical measurements.（2）The MnOx/g-C3N4/CdS/Pt hollow core-shell heterojunction is prepared via a continuous chemical-annealing-photoreduction method with SiO2 as template.There,the as-prepared MnOx/g-C3N4/CdS/Pt composite exhibits a remarkable overall water splitting performance of about～1303.39（H2）/641.60（O2）μmol/g·h.It was confirmed that the hollow core-shell microsphere structure g-C3N4/CdS heterostructure was successfully constructed and MnOx and Pt nanoparticles were deposited into inner shell layer by a series of testing methods such as SEM,TEM,EDS,Mapping,XRD and XPS.The g-C3N4/CdS heterojunction and hollow core-shell structure are regarded as the main reasons,in which,the Pt nanoparticles with quickly charge carriers transport can diffuse the photogenerated electrons into water,the formation of g-C3N4/CdS heterojunction can promote the photo-generated charge carriers transport.The introduction of MnOx and Pt nanoparticles as OER and HER co-catalysts respectively is the key factor to achieve overall water splitting.（3）The 1T/2H-MoS2/CdS/MnOx hollow nanosphere heterojunction is fabricated via a continuous hydrothermal-chemical method,there,the OER co-catalyst MnOx and CdS shells are deposited on the surface of SiO2 nanospheres templates continuously via hydrothermal-chemical method.Subsequently,the SiO2 templates are etched via chemical method and the 2H-MoS2/CdS heterojunction and 1T-MoS2 HER co-catalyst is introduced via one-step hydrothermal method.Evaluated by the photocatalytic performance,the 1T/2H-MoS2/CdS/MnOxexhibits an enhanced HER performance of about～50 folds than that of single CdS nanosphere,and achieve a decent overall water splitting performance of about～1668.00（H2）/824.61（O2）μmol/g·h,Which can be mainly ascribed to the 2H-MoS2/CdS heterojunction can separate the charge carrier and meet the potential to achieve overall water splitting,the 1T-MoS2 with sufficient specific surface areas can increase active sites,the 1T/2H-MoS2 with decent lattice matching can improve the charge carrier transport to enhance HER.On the other hand,the MnOx with mixed Mn3+/Mn4+ions can activate the hole-related species and promote H2O2 decomposition to enhance OER.Additionally,the hollow nanospheres can increase the solar efficiency and dispersibility,all these can enhance the overall water splitting performance and stability further. |
