Selective Regulation Of TiO 2 Crystal Faces In Different Dimensions And Their Photocatalytic Properties

At present,where the transfrom solar energy for useful purposes has obtained the attention of the scientific research worker.The use of solar energy for the electric power generation,coupled with its potential to produce fuels from CO2,CO2 and H2O by solar-induced photocatalyst materials,is a goal being improtant reserarch topic.TiO2 has also been one of most investigated photocatalyst materials during recent decades,especially in the green energy and environmental control applications.Howeve,TiO2 could only absorb UV light(E = 3.2 eV),rapid recombination of photoexcited charge carriers,so that decreases the photocatalytic activity.So,we hope to strategy for modifying the electronic structures by the development of TiO2 crystals with tailored facets,creating intrinsic defects and constructing heterostructures,and improving the performance in photocatalytic hydrogen production.1)Graphitic carbon nitride sheets(GCNS)were obtained through the direct ultrasonic exfoliation of bulk GCN in pure water,and hybridized heterojunction structures between the TiO2 nanorods and GCNS were fabricated by a facile production method.The introduction of GCNS can significantly increase the reactive sites for photocatalysis,form an efficient contact with TiO2 nanorods,and expand the visible-light-responsive region.The photocatalytic activities of TiO2 nanorods/GCNS under visible-light irradiation were about 3-and 10-times those of bulk GCN and TiO2 nanorods,respectively.The excellent photocatalytic performance of the TiO2 nanorods/GCNS was mainly attributed to the high separation and migration rate of electron-hole pairs and the efficient utilization of visible light.2)The grey crystal TiO2 sheets obtained from the protonic titanate sheets by hydrogen treatment under normal pressure exhibit a strong and persistent photocatalytic hydrogen production without the need of a co-catalyst such as Pt,Pd,or Au.Moreover,the photocatalytic activity of grey crystal TiO2 is also higher than that of the previous work reported such as reduction in H2/Ar under high pressure.These findings show that the main effect of the normal pressure H2 treatment on the protonic titanate sheets is the formation of carbon layer and stable Ti3+ defect sites,which represent an active catalytic center,as an intrinsic co-catalyst,for the hydrogen evolution of H2.The Ti3+/oxygen vacancies are beneficial for the electron transfer to the amorphous carbon shell,and carbon shell will protect the Ti3+/oxygel vacancies leading to the long-time photocatalytic stability for H2 evolution.3)The spatial loading of dual-cocatalysts on the different facets of a semiconductor is a novel and ideal approach to constructing an efficient photocatalytic system.Here,taking the series of antatse TiO2 as the research model,the photodeposition of dual-cocatalysts on the particular facet(001)and(101).Our results clearly show that Ag and FeOx as dual-cocatalysts could be photodeposited on the facet(101)and(101),which have water-spliting photocatalytic performance.