Synthesis And Photocatalytic Properties Of Composites Based On C₆₀ Derivatives And Semiconductor

Environmental pollution has become increasingly serious with the development of science and technology in recent years.Using photocatalysis of semiconductor materials to treat environmental pollution has received widespread attention,but semiconductor materials also have some problems,such as the recombination rate of photogenerated charges and holes is relatively high,affects the catalytic activity of semiconductors during photocatalysis.Therefore,it is necessary to select another material to modify semiconductor materials.Fullerene consists of sixty carbon atoms,fullerene which has a conjugated?structure and can effectively promote electron transfer for the reason that it is a good electron acceptor.The purpose of this thesis is to promote the electron transfer of the semiconductor material and thus improve its photocatalytic activity by using C₆₀carboxylic acid derivative C₆₀C?COOH?₂,whose water solubility and biocompatibility are better than C₆₀to modify different semiconductor material.The main contents of the thesis are as follows:1.A magnetic Fe₃O₄ core was prepared by solvothermal reaction.A shell of TiO₂was formed on the surface of Fe₃O₄ by hydrolysis of tetrabutyl titanate to prepare Fe₃O₄/TiO₂ core-shell nanoparticle.And then the prepared C₆₀C?COOH?₂ was carried on the outer surface of Fe₃O₄/TiO₂.A series of Fe₃O₄/TiO₂/C₆₀C?COOH?₂ which is a novel composite catalyst with different mass fractions of C₆₀C?COOH?₂ were obtained by changing the loading amount of C₆₀C?COOH?₂.The catalysts were characterized by different techniques,then its ability to degrade organic dye Rhodamine B was systematically studied,it was found that the composite materials which were doped C₆₀C?COOH?₂ as electron acceptor material exhibiting a synergistic effect so showing higher catalytic activity,solubility and biocompatibility to RhB compared with a single TiO₂.It was found that the photocatalytic performance was best when the loading amount of C₆₀C?COOH?₂ was 1.00 wt%.And then tested its cyclic performance,explored the impact of different capture agents on the catalytic effect.The saturation magnetization value of the composite material is 27.27 emu/g,showing that it can be separated under the action of an external magnetic field.The degradation efficiency of RhB is still above 80%after 4 cycles of experiments under visible light.2.Co-precipitation method was used to prepare Fe₃O₄ nanoparticles,then used sol-thermal method to coat the surface of Fe₃O₄ nanoparticles with a layer of ZnO nanoparticles to obtain Fe₃O₄/ZnO binary composite materials,and then C₆₀C?COOH?₂ was attached to the surface of Fe₃O₄/ZnO,a novel ternary series of Fe₃O₄/ZnO/C₆₀C?COOH?₂ composite materials were obtained.The catalytic activity of the ternary composite material to RhB is enhanced because of the reduction of the recombination probability of electrons and holes due to the electron transfer between the surface of ZnO and C₆₀C?COOH?₂.It was found that the loading of C₆₀C?COOH?₂was the highest in the degradation of RhB under visible light and ultraviolet light at2.00 wt%,and the efficiency became higher.The reason is mainly due to the electron transfer between the surface of ZnO and C₆₀C?COOH?₂,which reduces the recombination probability of electrons and holes.The magnetic properties of the catalyst,the cycling performance,and the effect of different trapping agents on the catalytic performance were also systematically studied.3.The CdS nanosheet was prepared by simple solvothermal method firstly.Then a series of CdS/C₆₀C?COOH?₂ composites over the mass fraction range of 0.25 wt%to 1.25 wt%were fabricated by C₆₀C?COOH?₂ combining with the flaky CdS nanomaterial.After characterized by different techniques in detail,the CdS/C₆₀C?COOH?₂ composites was used as catalyst for degradation of Rhodamine B?RhB?under visible light.Experiments results revealed that CdS/C₆₀C?COOH?₂ composites possessed higher absorption ability and photocatalytic activity due to efficient separation of photogenerated electron-hole pairs of C₆₀derivatives than sole CdS nanosheets.It is also found that CdS/C₆₀C?COOH?₂nanocomposite with 0.50 wt%C₆₀C?COOH?₂ content exhibited the highest photocatalytic degradation efficiency of RhB.Moreover,After four cycles,the efficiency of this composite as a catalyst for RhB degradation is also above 80%,which indicated that the composites were relative stable and could avoid the self-photocorrosion.4.The rod-like CdS was prepared by the solvothermal method,then,a thin layer of MoS₂ was attached to the rod-like CdS to obtain the CdS/MoS₂ composite material,and then the different quality of C₆₀C?COOH?₂ was compounded with the CdS/MoS₂.The properties of the material were characterized,and then we studied the photocatalytic activity of RhB.It was found that the composite material showed better catalytic effect than a single material because it reduced the hole and electron recombination rate due to the promotion of electron transfer.It was shown that the degradation of RhB had the fastest rate in UV and visible light when the mass fraction of C₆₀C?COOH?₂ at 0.50 wt%by testing a series of CdS/MoS₂/C₆₀C?COOH?₂composite materials.The cycling performance of the composite catalyst was studied and it was found that the degradation of Rh B under visible light can still be maintained at 80%after four cycles.