This study demonstrates the influence of the Ag^(+)/PO_(4)^(3-)ratio in precursor solution on the crystal structural formation,morphology,physical properties,and photocatalytic performance of a Ag_(3)PO_(4)photocataly...This study demonstrates the influence of the Ag^(+)/PO_(4)^(3-)ratio in precursor solution on the crystal structural formation,morphology,physical properties,and photocatalytic performance of a Ag_(3)PO_(4)photocatalyst that is fabricated,using a facile precipitation method,from AgNO_(3)and Na2HPO_(4)·12H_(2)O.The material characterizations were carried out using x-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive x-ray spectroscopy(EDX),Brunauer–Emmett–Teller(BET)surface area,Fourier transform infrared(FTIR)absorption,Raman scattering,x-ray photoelectron spectroscopy(XPS),UV-vis absorption,and photoluminescence(PL).The results show that Ag_(3)PO_(4)crystallizes better when the excess PO_(4)^(3-)content increases,and the lattice parameters decrease slightly,while the crystal diameter and the particle size increase.This change is also observed in the Raman scattering and FTIR spectra with the increase in the vibration frequency of the[PO_(4)]group.The compression of the[PO_(4)]unit was also confirmed in the XPS spectra with the shift of P 2p peaks toward higher binding energy.The photocatalytic results showed that the samples synthesized from excess PO_(4)^(3-)solution exhibited higher photocatalytic performance compared to the sample with a Ag^(+)/PO_(4)^(3-)ratio of 3:1.A sample prepared from the precursor solution with a Ag^(+)/PO_(4)^(3-)ratio of 3:1.5 was optimal for RhB decomposition under both visible light and natural sunlight,completely decomposing 10 ppm RhB after 15 minutes of xenon lamp irradiation and after 60 minutes under solar light irradiation.This is attributed to the high crystallinity,small particle size and low electron–hole recombination rate of the sample.展开更多
A series of Ca10Na(PO4)7:Ce3+/Tb3+/Mn2+(CNPO:Ce3+/Tb3+/Mn2+) phosphors with high brightness were synthesized by high-temperature solid-state method. X-ray diffraction(XRD), scanning electron microscopy(SEM), diffuse r...A series of Ca10Na(PO4)7:Ce3+/Tb3+/Mn2+(CNPO:Ce3+/Tb3+/Mn2+) phosphors with high brightness were synthesized by high-temperature solid-state method. X-ray diffraction(XRD), scanning electron microscopy(SEM), diffuse reflectance spectra(DRS), photo luminescence(PL) spectra, luminescence decay curves and thermally stability were performed to characterize the as-prepared samples. For Ce3+-doped samples, an intense and broad band emission is present under 265 nm excitation. When Ce3+and Tb3+are codoped, energy transfer(ET) process from Ce3+ to Tb3+ is demonstrated with electric dipole-dipole interaction. The internal and external quantum efficiencies(QEs) of CNPO:0.15 Ce3+, 0.04 Tb3+, 0.005 Mn2+are measured to 76.79% and 54.11% under 265 nm excitation and temperature-dependent PL intensity can remain 51.78% at 150 ℃ of its initial intensity at 25 ℃. It is indicated that single-phased white lightemitting CNPO:Ce3+/Tb3+/Mn2+phosphor can serve as a promising phosphor for illumination devices.展开更多
A red emitting phosphor of Ba_3Eu(PO_4)_3:Tb^(3+) was synthesized by a solid state method. The energy transfer from Tb^(3+) to Eu3+ in Ba_3Eu(PO_4)_3:Tb^(3+) was proved by the spectral properties and decay curves. The...A red emitting phosphor of Ba_3Eu(PO_4)_3:Tb^(3+) was synthesized by a solid state method. The energy transfer from Tb^(3+) to Eu3+ in Ba_3Eu(PO_4)_3:Tb^(3+) was proved by the spectral properties and decay curves. The emission intensity of Ba_3Eu(PO_4)_3 is enhanced by doping Tb^(3+) as a sensitizer. For Ba_3Eu(PO_4)_3:Tb^(3+), the ~5D_3→~7F_J transition of Tb^(3+) occurs, and the corresponding emission intensities can be tuned when Tb^(3+) content increases, and the concentration quenching effect appears. However, for the ~5D_4→~7F_J transition of Tb^(3+), its intensity straight increases with increasing Tb^(3+) content. For Ba_3Eu(PO_4)_3:Tb^(3+), the values of CIE chromaticity coordinates are similar to those of commercial red phosphors of Sr_2Si_5N_8:Eu^(2+) and Y_2O_2S:Eu^(3+). The results indicate that this red emitting phosphor has a potential application for white LEDs.展开更多
基金Project supported by a scientific and technological project at the level of Ministry of Education and Training(Grant No.B2020-MDA-11).
文摘This study demonstrates the influence of the Ag^(+)/PO_(4)^(3-)ratio in precursor solution on the crystal structural formation,morphology,physical properties,and photocatalytic performance of a Ag_(3)PO_(4)photocatalyst that is fabricated,using a facile precipitation method,from AgNO_(3)and Na2HPO_(4)·12H_(2)O.The material characterizations were carried out using x-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive x-ray spectroscopy(EDX),Brunauer–Emmett–Teller(BET)surface area,Fourier transform infrared(FTIR)absorption,Raman scattering,x-ray photoelectron spectroscopy(XPS),UV-vis absorption,and photoluminescence(PL).The results show that Ag_(3)PO_(4)crystallizes better when the excess PO_(4)^(3-)content increases,and the lattice parameters decrease slightly,while the crystal diameter and the particle size increase.This change is also observed in the Raman scattering and FTIR spectra with the increase in the vibration frequency of the[PO_(4)]group.The compression of the[PO_(4)]unit was also confirmed in the XPS spectra with the shift of P 2p peaks toward higher binding energy.The photocatalytic results showed that the samples synthesized from excess PO_(4)^(3-)solution exhibited higher photocatalytic performance compared to the sample with a Ag^(+)/PO_(4)^(3-)ratio of 3:1.A sample prepared from the precursor solution with a Ag^(+)/PO_(4)^(3-)ratio of 3:1.5 was optimal for RhB decomposition under both visible light and natural sunlight,completely decomposing 10 ppm RhB after 15 minutes of xenon lamp irradiation and after 60 minutes under solar light irradiation.This is attributed to the high crystallinity,small particle size and low electron–hole recombination rate of the sample.
基金supported by National Natural Science Foundation of China(51302182)Natural Science Foundation of Shanxi Province(201601d011030)
文摘A series of Ca10Na(PO4)7:Ce3+/Tb3+/Mn2+(CNPO:Ce3+/Tb3+/Mn2+) phosphors with high brightness were synthesized by high-temperature solid-state method. X-ray diffraction(XRD), scanning electron microscopy(SEM), diffuse reflectance spectra(DRS), photo luminescence(PL) spectra, luminescence decay curves and thermally stability were performed to characterize the as-prepared samples. For Ce3+-doped samples, an intense and broad band emission is present under 265 nm excitation. When Ce3+and Tb3+are codoped, energy transfer(ET) process from Ce3+ to Tb3+ is demonstrated with electric dipole-dipole interaction. The internal and external quantum efficiencies(QEs) of CNPO:0.15 Ce3+, 0.04 Tb3+, 0.005 Mn2+are measured to 76.79% and 54.11% under 265 nm excitation and temperature-dependent PL intensity can remain 51.78% at 150 ℃ of its initial intensity at 25 ℃. It is indicated that single-phased white lightemitting CNPO:Ce3+/Tb3+/Mn2+phosphor can serve as a promising phosphor for illumination devices.
文摘A red emitting phosphor of Ba_3Eu(PO_4)_3:Tb^(3+) was synthesized by a solid state method. The energy transfer from Tb^(3+) to Eu3+ in Ba_3Eu(PO_4)_3:Tb^(3+) was proved by the spectral properties and decay curves. The emission intensity of Ba_3Eu(PO_4)_3 is enhanced by doping Tb^(3+) as a sensitizer. For Ba_3Eu(PO_4)_3:Tb^(3+), the ~5D_3→~7F_J transition of Tb^(3+) occurs, and the corresponding emission intensities can be tuned when Tb^(3+) content increases, and the concentration quenching effect appears. However, for the ~5D_4→~7F_J transition of Tb^(3+), its intensity straight increases with increasing Tb^(3+) content. For Ba_3Eu(PO_4)_3:Tb^(3+), the values of CIE chromaticity coordinates are similar to those of commercial red phosphors of Sr_2Si_5N_8:Eu^(2+) and Y_2O_2S:Eu^(3+). The results indicate that this red emitting phosphor has a potential application for white LEDs.
