Fluorescence Properties of the Lanthanide Supported onto Titanate Nanosheets

Metal oxide nanosheets are increasingly used as catalysts, hard coatings and transparent thin films. Among these materials, TNSs （Titanate Nanosheets） synthesized in liquid phase enjoy particular attention due to their water dispersibility, photocatalytic activity, unique morphology and ease of synthesis. Importantly, the photo-induced redox reaction between TNSs and metal oxides affords potentially fluorescent metal-supported TNSs with enhanced photocatalytic activity, e.g., Ln/TNSs （Lanthaide-supported TNSs）. Herein, TNSs doped with arbitrary amounts of group 5 elements （M-TNSs： M = V, Nb and Ta） were prepared to investigate the fluorescent excitation spectra of Ln/M-TNSs and thus shed light on the mechanism of photodeposition and determine the origin of Ln/TNS fluorescence. As a result, photodepositiom was shown to involve phot-induced redox reaction between TNSs and lanthanide oxides, and the fluorescence intensity of Ln/TNSs and Ln/M-TNSs was demonstrated to be determined by the overlap of TNS and Ln3＋ excitation energies.

Facile Synthesis of Broadleaf-Shaped Titanate Nanosheets with Excellent UV Absorption Behavior

Broadleaf-shaped titanate nanosheets(B-TNSs)were synthesized via one-pot solvothermal method,and characterized by scanning electron microscopy,transmission electron microscopy,and X-ray diffraction etc.It is found that the synthesized B-TNSs consist of broadleaf-shaped nanosheet with a lateral size of ca.100 nm and a thickness of ca.1.2 nm.Owing to the ultrathin thickness,obvious blue shift of the absorption band edge can be observed in the absorption spectrum of B-TNSs resulting from quantum size effect.Besides,the specific surface area of B-TNSs is determined to be 348 m2/g,which is ca.6-fold larger than that of commercial P25 TiO2 nanoparticles.In the optical absorption experiment,B-TNSs exhibit much stronger absorption for ultraviolet light than P25 TiO2.These advantages of B-TNSs in morphological structure and optical absorption may make it a potential application in ultraviolet absorption and photocatalytic field.

Rationally designed ultrathin Ni(OH)_(2)/titanate nanosheet heterostructure for photocatalytic CO_(2) reduction

Dye-sensitized photocatalysis has been extensively studied for photocatalytic solar energy conversion due to the advantage in capturing long-wavelength photons with a high absorption coefficient.The rational integration of photosensitizer with semiconductor and cocatalyst to collaboratively operate in one system is highly desired.Here,we fabricate a Ni(OH)_(2)-loaded titanate nanosheet(Ni(OH)_(2)/H_(2)Ti_(6)O_(13))composite for high-performance dye-sensitized photocatalytic CO_(2) reduction.The ultrathin H_(2)Ti_(6)O_(13) nanosheets with negative surface charge provide an excellent support to anchor the dye photosensitizer,while the loaded Ni(OH)2 serves as an adsorbent of CO_(2) and electron sink of photoelectrons.As such,the photoelectrons derived from the[Ru(bpy)3]Cl_(2) sensitizer can be targeted transfer to the Ni(OH)_(2) active sites via the H_(2) Ti_(6)O_(13) nanosheets linker.A high CO production rate of 1801μmol g^(-1) h^(-1) is obtained over the optimal Ni(OH)_(2)/H_(2)Ti_(6)O_(13),while the pure H_(2)Ti_(6)O_(13) shows significantly lower CO_(2) reduction performance.The work is anticipated to trigger more research attention on the rational design and synthesis of earth-abundant transition metal-based cocatalysts decorated on ultrathin 2D platforms for artificially photocatalytic CO_(2) reduction.