YPO4 phosphors single-doped with Sb3+ or Gd3+ and co-doped with Sb3+ and Gd3+ were prepared by a solid-state reaction method. The phase purity, morphology, photoluminescence excitation and emission properties of the prepared phosphors were investigated. The results showed that Sb3+ could sensitize Gd3+ in the co-doped phosphors which made the phosphors excitable by short-wave ultraviolet (UV) at a wavelength between 220 and 260 nm. Under 253.7 nm excitation, the co-doped phosphors Y1-x-yPO4: Sb3+x,Gd3+y showed strong emission of Gd3+ at a wavelength of 312 nm whose intensity changed with the doping concentrations of Gd3+ and Sb3+. The optimized Y0.77PO4:Sb3+0.07,Gd3+0.16 phosphor showed an intensity comparable to commercial LaPO4:Ce phosphor (UVB-315), making it a potential candidate for mercury low-pressure discharge narrow-band UV-B emitting lamps.PL spectrum of Y0.77PO4:Sb0.07Gd0.16 calcined at 1400 °C and of commercial phosphor UVB-315 under excitation of 253.7 nm

LaPO4:Ce,Tb phosphor was prepared by firing the LaPO4:Ce,Tb precipitate derived from co-precipitation of aqueous solution of LaCeTb mixed rare earth nitrate with ammonium dibasic phosphate. Effects of ripening condition of precipitate, flux addition and firing temperature on the morphology and photoluminescence properties of LaPO4:Ce,Tb phosphor were investigated. It was found that ripening of LaPO4,Ce,Tb precipitate with mother liquor at pH = 1 and 130 °C for 24 h produced strip phosphor with width of 100 nm and length of 1 μm. While ripening at either 85 or 130 °C after pH adjustment with ammonia generated spherical particles of about 100 nm in size. Types of flux employed significantly influenced the morphology of the phosphor. When H3BO3 was used as flux spherical particles of ca. 300 nm were formed. In contrast, when Li2CO3 or Li3PO4 was employed as flux either separately or a component of double flux, uniform spherical or near spherical particles of ca. 5 μm were generated. Firing temperature of 1100 and 1200 °C in the presence of double flux led to the formation of smooth spherical particles with diameter of ca. 5 μm, and the phosphor prepared with double flux showed higher brightness than the commercial phosphor.LaPO4:Ce,Tb green phosphor was prepared by firing the LaPO4:Ce,Tb precipitate synthesized by co-precipitation of aqueous solution of LaCeTb mixed rare earth nitrate with ammonium dibasic phosphate. Effects of ripening condition of precipitate, flux addition and firing temperature on the morphology and photoluminescence properties of LaPO4:Ce,Tb phosphor were studied.

Effect of MgAl2O4 on the structure, acidity as well as the catalytic performance of Nb2O5/α-Al2O3 catalyst for ethylene oxide hydration was studied using IR, XRD, NH3-TPD, CO2-TPD and catalytic reaction. Modification of α-Al2O3 support with MgAl2O4 led to an increase in both basicity and mechanical strength of the support. As a result, the density and strength of the acidity of the niobium oxide catalyst supported on the MgAl2O4 modified α-Al2O3 reduced in comparison with that supported on the pure α-Al2O3. The acidity of 10% Nb2O5/MgAl2O4/α-Al2O3 decreased with increasing loading of MgAl2O4. Catalytic test showed that EO conversion decreased monotonously with increasing MgAl2O4 loading, whereas the selectivity to MEG exhibited a maximum of 90.6% at MgAl2O4 loading of 2.23%. In terms of MEG yield, optimal MgAl2O4 loading should be around 2%. Durability test demonstrated that 10% Nb2O5/MgAl2O4/α-Al2O3 catalyst exhibited excellent stability within 1000 h time-on-stream.Effect of modification of α-Al2O3 support with MgAl2O4 on the structure, acidity as well as the catalytic performance of Nb2O5/α-Al2O3 catalyst for ethylene oxide hydration was studied using IR, XRD, NH3-TPD, CO2-TPD and catalytic reaction.