By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), T...By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn 3(PO 4) 2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu 3+ exists as EuPO 4 in the powder. In the phosphor powders, the Eu 3+ shows its characteristic red-orange (592 nm, 5D 0- 7F 1) emission and has no quenching concentration.展开更多
Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(...Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.展开更多
KF Zn 3(PO 4) 2 catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O 2 concentration in feed gas on isobutene yield and selectivity were discussed. The modi...KF Zn 3(PO 4) 2 catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O 2 concentration in feed gas on isobutene yield and selectivity were discussed. The modification of zinc phosphate by potassium fluoride leads to the formation of a new compound KF Zn 3(PO 4) 2 and surface basic sites, the catalytic performance of which is thus improved.展开更多
Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts wer...Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts were enhanced significantly j The activity of the most active sample. 60%SZ/Al_2O3-P, was even about 2 times more active than that of the SZ catalyst.展开更多
文摘By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn 3(PO 4) 2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu 3+ exists as EuPO 4 in the powder. In the phosphor powders, the Eu 3+ shows its characteristic red-orange (592 nm, 5D 0- 7F 1) emission and has no quenching concentration.
基金support from the National Natural Science Foundation of China(51402100,21905088,21573066 and U19A2017)the Provincial Natural Science Foundation of Hunan(2020JJ5044,2022JJ10006)。
文摘Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.
文摘KF Zn 3(PO 4) 2 catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O 2 concentration in feed gas on isobutene yield and selectivity were discussed. The modification of zinc phosphate by potassium fluoride leads to the formation of a new compound KF Zn 3(PO 4) 2 and surface basic sites, the catalytic performance of which is thus improved.
文摘Highly active solid superacid catalysts for n-butane isomerization, SZ/A1_2O_3-P, were prepared by supporting SO-(4-2)/ZrO2, (SZ) on y-A1_2O_3 carrier using a precipitation method. The activities of some catalysts were enhanced significantly j The activity of the most active sample. 60%SZ/Al_2O3-P, was even about 2 times more active than that of the SZ catalyst.
