Preparation And Photocatalytic Properties Of Radial Rutile Microspheres And Their Assemblies

One of the most efficient and stable benchmark photocatalysts,titanium dioxide（TiO₂）has broad development prospect due to high chemical stability,low cost,and excellent photoelectrochemical characteristics.However,rutile TiO₂ is the most thermodynamically stable catalyst and usually presents rapid photoexcited electron–hole recombination and exhibits low photocatalytic performance compared with the anatase phase,which can be ascribed to its direct bandgap semiconductor characteristic and nearly inert surface in the stoichiometric form.However,rutile has higher chemical stability,narrower band gap and higher refractive index than anatase,which means it may be a promising photocatalyst.In this work,we have constructed single-crystal rutile TiO₂nanorods through solvothermal method that are assembled into radial microspheres through nucleation and the seed-oriented growth approach.As the host,a series of architectures were constructed by wet-impregnation method and in-situ photodegradation method to broaden the photoresponse range and improve the efficiency of carrier separation to enhance the photocatalytic activity of the catalyst.The relationship between the preparation of radial rutile microspheres with their complexes and the photocatalytic performance are studied in this paper,which are mainly divided into the following three aspects:1.Single-crystal rutile TiO₂ nanorods that are assembled into radial microspheres with a diameter of～2μm were prepared by solvothermal method and in-situ chemisorbed Cl on the surface through nucleation and the seed-oriented growth approach,which form stable Surfae Domain Heterojunctions（SDHs）.Under the condition of simulated sunlight AM 1.5G,radial rutile microspherrs decorated with Cl exhibited excellent photocatalytic hydrogen evolution performance(15.9 mmol h^-1 g^-1),about 8-fold higher than that of the pristine one(0.19 mmol h^-1 g^-1)without decorated Cl.2.Using Cl-decorated radial rutile microspheres as the host materials,Cu nanoparticle/Pt nanoparticle/radial rutile microspheres composites（CuPt-RT-Cl）were prepared by ultrasonic impregnation in dark,liquid nitrogen freezing and in-situ photoreduction.Pt and Cu nanoparticles with a diameter of were dispersed on the surface of microspheres.CuPt-RT-Cl exhibited excellent photocatalytic hydrogen evolution performance(24.8 mmol h^-1 g^-1),about 1.56 times as higher as that of RT-Cl.And the introduction of base metal element Cu also reduces the cost of cocatalyst,which provides a feasible idea for the design of photocatalyst in practical application.3.We introduced transition metal sulfides CdS by in-situ impregnation method,CdS/radial rutile microsphere heterojunctions（CdS-RT-Cl）were constructed.The CdS clusters grew at the core of the radial microsphere,which greattly enhanced the photoresponse of the catalyst under the visible light and the bandgap was reduced to 2.66e V.CdS-RT-Cl exhibited excellent photocatalytic hydrogen evolution performance(14.6mmol h^-1 g^-1)without noble metal Pt,were about 4.5 times as higer as that of RT-Cl.