The Modification Of Titanoniobate Nanosheets And Its Application As The Support Of Photocatalytic Materials

In this paper,nitrogen-doped titanoniobate nanosheets(N-HTiNbO5-NS)aggregation was successfully obtained through modifying the precursor layered KTiNbO5,which was prepared by high temperature solid-state reaction method,including these process of nitrogen-doping,H+ ion-exchanging and exfoliation.The photocatalytic activity of the as-prepared samples was investigated by the photocatalytic degradation of methylene blue(MB)under visible light irradiation.Two kinds of nano-composite photocatalytic materials were constructed by using N-HTiNbO5-NS as the carrier,and two kinds of transition metal oxides MOx(M=Zn,Fe)as the complex,respectively.The reaction of photocatalytic adsorption and degradation for ethyl mercaptan(EM)were performed as probe experiments to investigate the photocatalytic performance of compound materials.The structure and physical chemical properties of the as-prepared samples were characterized by a variety of analytical methods,such as X-ray powder diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),N2 adsorption-desorption,UV-vis diffuse reflectance spectroscopy(UV-vis DRS),laser Raman spectroscopy(LRS),X-ray photoelectron spectroscopy(XPS)and thermal analysis(TG-DSC),etc.The photocatalytic performance of N-HTiNbO5-NS was preliminary evaluated by the degradation of methylene blue(MB)under visible light irradiation.Further more,the gas chromatography(GC)analysis was used to detect the ability of MOx/N-HTiNbO5-NS(M=Zn,Fe)in adsorption and degradation of ethyl mercaptan(EM).The results indicated that the layered KTiNbO5 was successfully prepared by high temperature solid-state reaction method.The nitrogen element coexist in forms of substitution and interstitial N in the crystal lattice,meanwhile,the doping reaction did not cause the change of materials layered structure.But however,the introduction of nitrogen leads to the change of the band structure of the catalysts,which makes the band gap narrow.The N-HTiNbO5-NS with lamellar pile-up structure was prepared by modifying the N-KTiNbO5 through the methods of proton-exchanging,exfoliation and acid deposition.The as-prepared N-HTiNbO5-NS shows relatively strong photocatalytic activity for degradation of methylene blue(MB),which may be attributed to the effect of increased specific surface area and narrowed band gap energy.The MOx/N-HTiNbO5-NS(M=Zn,Fe)composites constructed by means of composite modification still maintain the stacked structure of nanosheets,and the metal oxide nanoparticles are uniformly dispersed on the surface of nanosheets.The composites shows a larger surface area and pore volume compared with its precursor,this may be due to nanoparticles has a large surface area in itself,and larger pore was formed by restacking nanoparticles with nanosheets.A high visible light response ability was observed which may be arised to a narrow band gap which caused by the new band structure of MOx/N-HTiNbO5-NS composites.The MOx/N-HTiNbO5-NS composites exhibit excellent capability in the adsorption and degradation of ethyl mercaptan(EM)under visible light irradiation.Due to the quantum size effect of the oxide particles and the synergistic effect between nanoparticles and carrier,the composite materials shows a good performance of desulfurization.In conclusion,the construction of metal oxide and layered nanosheets composites provides a feasible way for the synthesis of novel photocatalytic desulfurization materials.