Controllable Synthesis And Performance Research Of New-structured Composite Semiconductor Photocatalyst

Semiconductor photocatalysts are of great potential for their effectiveness inutilizing solar sight, harnessing renewable-energy sources, and environmental protectionand remediation. However, the poor ability to adsorb reactants, the narrow range ofspectrum response, and the low quantum efficiency lead to the poor activity ofphotocatalysts, thus exploring advanced photocatalysts that have improved performancehas been a central theme in photocatalysis research.Considering the problems mentioned above, this thesis focuses on the followingaspects:(1) Fabrication and modification of traditional photocatalysts with an emphasison structural and composition control. The photocatalytic activity of some well-knownphotocatalysts can be improved by the means of structure-and composition-engineering;(2) Preparation of metal sulfide solid solution photocatalysts with porous sphere-likestructure. The high photocatalytic activity can be achieved based on the change ofcomposition and the adjustment of bang gap;(3) Synthesis and exploration of somenovel effective photocatalysts with zero-dimensional structure. The mono-dispersedniobium salt with excellent activity and the loaded ultrafine Au particles can beprepared by low temperature solvothermal method without addition of any cappingreagent.Chapter1: In this part, the author introduces the history of semiconductorphotocatalyst materials and the mechanism of photocatalytic reactions. The advances insemiconductor photocatalysis research and the status of hollow structures are reviewed.In addition, the frequently-used optimization methods of photocatalysts and thedirection of their future development are also summarized.Chapter2: A simple template-free one-pot method is used to synthesize CdS andNi-doped CdS hollow spheres in this part. The products are uniformed hollow sphereswith good dispersity. By optimizing the dosage of Ni2+, the photocatalytic activity ofCdS is improved. The study shows that Ni-doped CdS hollow spheres can remove organic pollutants RhB and phenol efficiently. The formation mechanism and thesuperior photocatalytic activity for the Ni-doped CdS hollow spheres are discussed indetails.Chapter3: On basis of CdS, a series of N-doped ZnxCd1-xS solid solutions withporous spherical morphology are fabricated by solvothermal method in this part. Thelower Cd2+content, higher specific surface area and stronger stability againstphotocorrosion make the prepared samples to be a promising visible light responsephotocatalyst for organic pollutants X3B and phenol removal. The brilliant activitymechanism of ZnxCd1-xS solid solutions are also discussed based on the bang gapadjustment.Chapter4: In this part, a low temperature solvothermal method is employed toprepare SrNb6O16nanoparticles and loaded Au nanoparticles without any cappingreagent addition. The synthesized SrNb6O16nanoparticles are uniformed andmono-dispersed. It shows high activity for organic dye RhB degradation. The loadedultrafine Au nanoparticles have great value in related research.Chapter5: In this part, the author summarizes the achievements of this thesissystematically. Combining the positive result with the main opportunities andchallenges confronted by photocatalyst materials, the author proposes the futuredevelopment direction and prospect of photocatalysts.