Study On The Preparation Of Aligned And Highly Exposed Facets Of TiO₂ And Their Performances For Photocatalytic Water Splitting

Due to the rich reserves of solar energy and the advantages of hydrogen energy is cleanling and easy of use,photocatalytic water splitting to produce hydrogen is considered as an ideal solution to energy shortage and environmental pollution.TiO₂ has many good features,such as high photocatalytic activity,good stability and abundance in nature.Meanwhile,it has no toxicity to human body.For these reasons,the study of TiO₂has been a research hotspot in the field of photocatalysis.The photocatalytic activities of TiO₂ crystals vary with different facets exposure,because of different arrangement orders and coordination environment of atoms.Although the high energy facets can effectively improve the photocatalytic activity of TiO₂,there still exist some disadvantages,such as the high recombination rate of electrons and holes.On the basis of progress in highly exposured facets of TiO₂,this dissertation aims to improve the separation efficiency of electrons and holes via continuous orientation assembling by the regulation charge transportation,thus to enhance the photocatalytic activities of the catalysts.The as-prepared aligned and highly exposured facets TiO₂ fibers were also doped with N elements to make it having visible light response.The main contents are listed as follows:?1?{010}TiO₂ was prepared by hydrothermal method,and the continuous and orientatied assembling of{010}TiO₂ was realized by electrospinning.The as-fabricated aligned{010}TiO₂ fibers were arranged closely with regular distributing and without changing the expoure of{010}facets.The photocatalytic hydrogen evolution of aligned{010}TiO₂ fiber is 32%higher than that of unassembled{010}TiO₂,and 12%higher than that of unaligned{010}TiO₂ fibers.In combination with the characterization of oproelectrical properties,it is speculated that the aligned{010}TiO₂ fibers have the optimized migration path of photogenerated electrons and holes,and the enhanced utilization rate of light by strengthening the scattering.?2?On the basis of the preparation of aligned{010}TiO₂ fibers,it was founded that N-aligned{010}TiO₂ fibers were prepared via calcination in NH₃ atmosphere.The N elements could substitude lattice oxygen,leading to the doping level among the semiconductor and reduce the band gap of TiO₂,and bring about the visible light absorption.The evaluation of photocatalytic hydrogen evolution under visible light irradiation shows that the as-prepared N-aligned{010}TiO₂ fiber has the optimized activity of 81?mol/?g.h?.