This paper reported the thermal stability and spectroscopic properties of Ga2O3-GeO2-Na2O-K2O （GGNK） glasses doped with Er3＋. The GGNK glasses were characterized by differential scanning calorimetry （DSC）, Raman ...This paper reported the thermal stability and spectroscopic properties of Ga2O3-GeO2-Na2O-K2O （GGNK） glasses doped with Er3＋. The GGNK glasses were characterized by differential scanning calorimetry （DSC）, Raman spectra, absorption and infra- red-visible fluorescence spectra. Measured DSC result showed that these glasses possessed an excellent stability （AT=188.6 ℃）. The relationship between glass composition and Judd-Ofelt intensity parameters and other optical properties of Er3＋, such as the absorption and stimulated emission cross-sections, were clarified. Meanwhile an intense broadband 1.53μm emission with a full width at half- maximum of 51 nm and peak emission cross-section of 9.32×10^-21 cm2 of Er3＋-doped GGNK glass was obtained upon 980 nm di- ode-laser excitation. Effects of K2O replacing Na2O on the thermal stability and spectroscopic properties were investigated. It was found that the incorporation of K2O into Er3＋-doped Ga2O3-GeO2-Na2O glass could effectively improve the 1.53 μm emission luminescence. The results showed that GGNK glass might be more attractive host material for their application in C-band optical fiber amplifiers.展开更多
β-Ga_(2)O_(3)以其较高的导带底(Conduction Band Minimum,CBM)和较低的价带顶(Valence Band Maximum,VBM),赋予其光生电子和空穴较强的还原与氧化能力,但其宽禁带和高载流子复合率限制了在光催化中的应用.金属离子掺杂被认为是提升光...β-Ga_(2)O_(3)以其较高的导带底(Conduction Band Minimum,CBM)和较低的价带顶(Valence Band Maximum,VBM),赋予其光生电子和空穴较强的还原与氧化能力,但其宽禁带和高载流子复合率限制了在光催化中的应用.金属离子掺杂被认为是提升光催化性能的有效途径.本文基于第一性原理系统研究了Sr、Ba、V、Nb、Ta等二十种元素掺杂对β-Ga_(2)O_(3)光催化性能的影响,研究发现:Sr、Nb、Ta、Mn、Fe、Zn、Hg七种元素掺杂β-Ga_(2)O_(3)后,材料除能保持合适的带边位置外,还具有更高的电子空穴分离效率以及更低的形成能,表明这些元素的引入可有效提升β-Ga_(2)O_(3)光催化效率;Nb、Ta掺杂可显著增强材料在红外光区的吸收,Mn、Fe掺杂则显著提升材料在紫外和可见光区的吸收能力,其中,Nb在0.5 eV处光吸收系数高达1.38×10^(5)cm^(−1),Mn、Fe掺杂在3 eV处光吸收系数可达1×10^(5)cm^(−1),在不同波段均呈现出良好的光吸收能力.此外,Hg掺杂表现出跨红外至深紫外的宽波段增强效果,Hg掺杂后,电子空穴相对有效质量高达109,说明Hg掺杂显著提升载流子分离能力,同时由于其在宽波段显著增强的光吸收效果,因此,Hg可作为β-Ga_(2)O_(3)在光催化制氢中理想的金属掺杂元素,以上研究结果为β-Ga_(2)O_(3)光催化分解水制氢研究提供了价值参考.展开更多
This study presented the luminescence properties of Nd^3＋/Yb^3＋/Ho^3＋ dopant ions inside a host based on Ga_2O_3-GeO_2-Li_2O（GGL） glass. The measured differential scanning calorimetry result showed that GGL glass...This study presented the luminescence properties of Nd^3＋/Yb^3＋/Ho^3＋ dopant ions inside a host based on Ga_2O_3-GeO_2-Li_2O（GGL） glass. The measured differential scanning calorimetry result showed that GGL glass exhibited excellent stability against devitrification with ？T=135 oC. Obvious 543 and 657 nm emissions were observed in Nd^3＋/Ho^3＋-codoped sample. The incorporation of Yb^3＋ into Nd^3＋/Ho^3＋-codoped glass system had resulted in enhanced upconversion emission intensity under the excitation of 808 nm and/or 980 nm laser diode（LD）. The possible mechanisms and related discussions on this phenomenon were presented. It was noted that the presence of Yb^3＋ yielded an enhancement about 7 and 11 times in the 543 and 657 nm emission intensities respectively under 808 nm excitation due to the energy transfer from Nd^3＋ to Ho^3＋ via Yb^3＋ ion. Here Yb^3＋ played a major role as a bridging ion. While enhanced 543 and 657 nm emission intensities under the excitation of 980 nm LD originated from the sensitization effect of Yb^3＋. Our results showed that Nd^3＋/Ho^3＋/Yb^3＋ triply doped GGL glass might be a promising candidate for the development of visible-laser materials.展开更多
The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonizatio...The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.展开更多
研究了 Ga_2O_3/Al_2O_3 膜反应自组装制备 GaN 薄膜。首先利用磁控溅射法在硅衬底上制备 Ga_2O_3/Al2O3膜,再将Ga_2O_3/Al_2O_3 膜在高纯氨气气氛中氨化反应得到了 GaN 薄膜。用 X 射线衍射(XRD),X 光光电子能谱(XPS)、扫描电镜(SEM)...研究了 Ga_2O_3/Al_2O_3 膜反应自组装制备 GaN 薄膜。首先利用磁控溅射法在硅衬底上制备 Ga_2O_3/Al2O3膜,再将Ga_2O_3/Al_2O_3 膜在高纯氨气气氛中氨化反应得到了 GaN 薄膜。用 X 射线衍射(XRD),X 光光电子能谱(XPS)、扫描电镜(SEM)、透射电镜(TEM)和 荧光光谱(PL)对样品进行结构、组分、形貌和发光特性的分析。测试结果表明:用此方法得到了六方纤锌矿结构的 GaN 晶体膜。展开更多
A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this c...A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this compound crystallizes in the orthorhombic space group Pbca, a =1.605 6(7) nm, b = 1 011 4 (4) nm, c =1.854 6(5) nm, V =3.011 6(19) nm 3, Z =4. The three dimensional framework based on linkage of corner sharing polyhedron PO 4, GaO 4F and GaO 4F 2 delimit ten ring channels along b axis in which the triply protonated amines are located serving as charge compensating vips and supporters.展开更多
基金Project supported by the National Natural Science Foundation of China(51002070)Funding Scheme for Young Teachers ofHigher School in Henan Province(2012GGJS-192)
文摘This paper reported the thermal stability and spectroscopic properties of Ga2O3-GeO2-Na2O-K2O （GGNK） glasses doped with Er3＋. The GGNK glasses were characterized by differential scanning calorimetry （DSC）, Raman spectra, absorption and infra- red-visible fluorescence spectra. Measured DSC result showed that these glasses possessed an excellent stability （AT=188.6 ℃）. The relationship between glass composition and Judd-Ofelt intensity parameters and other optical properties of Er3＋, such as the absorption and stimulated emission cross-sections, were clarified. Meanwhile an intense broadband 1.53μm emission with a full width at half- maximum of 51 nm and peak emission cross-section of 9.32×10^-21 cm2 of Er3＋-doped GGNK glass was obtained upon 980 nm di- ode-laser excitation. Effects of K2O replacing Na2O on the thermal stability and spectroscopic properties were investigated. It was found that the incorporation of K2O into Er3＋-doped Ga2O3-GeO2-Na2O glass could effectively improve the 1.53 μm emission luminescence. The results showed that GGNK glass might be more attractive host material for their application in C-band optical fiber amplifiers.
文摘β-Ga_(2)O_(3)以其较高的导带底(Conduction Band Minimum,CBM)和较低的价带顶(Valence Band Maximum,VBM),赋予其光生电子和空穴较强的还原与氧化能力,但其宽禁带和高载流子复合率限制了在光催化中的应用.金属离子掺杂被认为是提升光催化性能的有效途径.本文基于第一性原理系统研究了Sr、Ba、V、Nb、Ta等二十种元素掺杂对β-Ga_(2)O_(3)光催化性能的影响,研究发现:Sr、Nb、Ta、Mn、Fe、Zn、Hg七种元素掺杂β-Ga_(2)O_(3)后,材料除能保持合适的带边位置外,还具有更高的电子空穴分离效率以及更低的形成能,表明这些元素的引入可有效提升β-Ga_(2)O_(3)光催化效率;Nb、Ta掺杂可显著增强材料在红外光区的吸收,Mn、Fe掺杂则显著提升材料在紫外和可见光区的吸收能力,其中,Nb在0.5 eV处光吸收系数高达1.38×10^(5)cm^(−1),Mn、Fe掺杂在3 eV处光吸收系数可达1×10^(5)cm^(−1),在不同波段均呈现出良好的光吸收能力.此外,Hg掺杂表现出跨红外至深紫外的宽波段增强效果,Hg掺杂后,电子空穴相对有效质量高达109,说明Hg掺杂显著提升载流子分离能力,同时由于其在宽波段显著增强的光吸收效果,因此,Hg可作为β-Ga_(2)O_(3)在光催化制氢中理想的金属掺杂元素,以上研究结果为β-Ga_(2)O_(3)光催化分解水制氢研究提供了价值参考.
基金Project supported by the National Natural Science Foundation of China(51002070)Foundation of He’nan Educational Committee(14A430034,16A430040)+1 种基金Funding Scheme for Young Teachers of Higher School in Henan Province(2012GGJS-192)the Science and Technology Program of Luoyang City(1401051A)
文摘This study presented the luminescence properties of Nd^3＋/Yb^3＋/Ho^3＋ dopant ions inside a host based on Ga_2O_3-GeO_2-Li_2O（GGL） glass. The measured differential scanning calorimetry result showed that GGL glass exhibited excellent stability against devitrification with ？T=135 oC. Obvious 543 and 657 nm emissions were observed in Nd^3＋/Ho^3＋-codoped sample. The incorporation of Yb^3＋ into Nd^3＋/Ho^3＋-codoped glass system had resulted in enhanced upconversion emission intensity under the excitation of 808 nm and/or 980 nm laser diode（LD）. The possible mechanisms and related discussions on this phenomenon were presented. It was noted that the presence of Yb^3＋ yielded an enhancement about 7 and 11 times in the 543 and 657 nm emission intensities respectively under 808 nm excitation due to the energy transfer from Nd^3＋ to Ho^3＋ via Yb^3＋ ion. Here Yb^3＋ played a major role as a bridging ion. While enhanced 543 and 657 nm emission intensities under the excitation of 980 nm LD originated from the sensitization effect of Yb^3＋. Our results showed that Nd^3＋/Ho^3＋/Yb^3＋ triply doped GGL glass might be a promising candidate for the development of visible-laser materials.
基金supported by the National Natural Science Foundation of China(Nos.22276060 and 21976059)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012636)China Scholarship Council Scholarship(No.201906155006)。
文摘The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.
文摘研究了 Ga_2O_3/Al_2O_3 膜反应自组装制备 GaN 薄膜。首先利用磁控溅射法在硅衬底上制备 Ga_2O_3/Al2O3膜,再将Ga_2O_3/Al_2O_3 膜在高纯氨气气氛中氨化反应得到了 GaN 薄膜。用 X 射线衍射(XRD),X 光光电子能谱(XPS)、扫描电镜(SEM)、透射电镜(TEM)和 荧光光谱(PL)对样品进行结构、组分、形貌和发光特性的分析。测试结果表明:用此方法得到了六方纤锌矿结构的 GaN 晶体膜。
文摘A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this compound crystallizes in the orthorhombic space group Pbca, a =1.605 6(7) nm, b = 1 011 4 (4) nm, c =1.854 6(5) nm, V =3.011 6(19) nm 3, Z =4. The three dimensional framework based on linkage of corner sharing polyhedron PO 4, GaO 4F and GaO 4F 2 delimit ten ring channels along b axis in which the triply protonated amines are located serving as charge compensating vips and supporters.
