Phosphoric Acid Functionalized Cnts - Tio < Sub > 2 < / Sub > Building And Its Photocatalytic Performance Improvement Mechanism Of Composite Materials

Recently, the research about carbon nanotube-TiO₂（CNTs-TiO₂） nanoparticlecomposites has been widely reported. However, it is still necessry to investigate thesynthesis method and reaction mechanism, especially the role of carbon nanotube （CNT）in the composites.Based on the previous work in our team, we further insight into the synthesis andreaction mechanism of the CNTs-TiO₂nanoparticle composites fabricated bywater-organic two-phase separated hydrolysis-solvothermal （HST） processes. The keyto this method is that CNTs is covered with titanium（IV） n-butoxide stably, aiming toguarantee the homodisperse of CNTs in the solvent of toluene and in-situ hydrolysis oftitanium（IV） n-butoxide and crystallization process on the surface of the CNTs. Theresults show that CNTs-TiO₂nanocomposite with appropriate amount of CNTs exhibitsgood photocatalytic activity for the photocatalytic degradation of rhodamine （RhB）, butpoor activity for phenol and aldehyde. The O₂-TPD and SPS results clearly indicate thatthe increase of photocatalytic degradation of RhB is mainly attibuted to the strongadsorption of CNTs-TiO₂nanocomposite, which is favorable to the indirect oxidationand self-oxidation of RhB. However, the poor photocatalytic activity of phenol andaldehyde may be ascribed to the bad electron reduction ability of oxygen on CNTs. It ispossible that carbon-based materials constructing composites have common problems inthe photocatalytic process.In order to solve above problems, we have successfully constructed phosphoricacid modified CNTs （CP） by direct impregnation-calcinations method and furthersynthesize phosphoric acid modified CNTs-TiO₂（CPT） nanoparticle composites by HSTand simple wet chemical method. CPT could effectively improve the photocatalyticactivity not only in degradation of RhB, but also phenol and aldehyde. The O₂-TPD andSPS results demonstrate that CP is favorable to the effective combination. In addition,CP could also enhance the ability to adsorption of O₂on the surfaces of CNTs, and thenimprove the photocatalytic activity of CPT. In this work, phosphoric acid modified CNTs are innovatively synthesized bysimple impregnation-calcination method. What is more, the reactive capability ofphoto-induced electron is significantly improved in the composites due to accelerate theadsorbed O₂, and the photocatalytic ability is effectively enhanced. This work willprovide a theoretical and practical strategy to deeply study the reactive mechanism andimproving strategy of carbon-based photocatalytic functional nanomaterials.