Novel graphitic carbon nitride(g-C_(3)N_(4))nanosheet/Bi_(5)O_(7)Br/NH_(2)-MIL-88B(Fe)photocatalysts(denoted as GCN-NSh/Bi_(5)O_(7)Br/FeMOF,in which MOF is metal–organic framework)with double S-scheme heterojunctions...Novel graphitic carbon nitride(g-C_(3)N_(4))nanosheet/Bi_(5)O_(7)Br/NH_(2)-MIL-88B(Fe)photocatalysts(denoted as GCN-NSh/Bi_(5)O_(7)Br/FeMOF,in which MOF is metal–organic framework)with double S-scheme heterojunctions were synthesized by a facile solvothermal route.The resultant materials were examined by X-ray photoelectron spectrometer(XPS),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDX),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),photoluminescence spectroscopy(PL),Fourier transform infrared spectroscopy(FT-IR),UV-Vis diffuse reflection spectroscopy(UV-vis DRS),photocurrent density,electrochemical impedance spectroscopy(EIS),and Brunauer–Emmett–Teller(BET)analyses.After the integration of Fe-MOF with GCN-NSh/Bi_(5)O_(7)Br,the removal constant of tetracycline over the optimal GCN-NSh/Bi_(5)O_(7)Br/Fe-MOF(15wt%)nanocomposite was promoted 33 times compared with that of the pristine GCN.The GCN-NSh/Bi_(5)O_(7)Br/Fe-MOF(15wt%)nanocomposite showed superior photoactivity to azithromycin,metronidazole,and cephalexin removal that was 36.4,20.2,and 14.6 times higher than that of pure GCN,respectively.Radical quenching tests showed that·O_(2)-and h+mainly contributed to the elimination reaction.In addition,the nanocomposite maintained excellent activity after 4 successive cycles.Based on the developed n–n heterojunctions among n-GCN-NSh,n-Bi_(5)O_(7)Br,and n-Fe-MOF semiconductors,the double S-scheme charge transfer mechanism was proposed for the destruction of the selected antibiotics.展开更多
Novel graphene-like boron nitride(BN)/Bi_(3)O_(4)Br photocatalysts have been controllably synthesized through a facile solvothermal method for the first time. Layer contact stacking between graphene-like BN and ultrat...Novel graphene-like boron nitride(BN)/Bi_(3)O_(4)Br photocatalysts have been controllably synthesized through a facile solvothermal method for the first time. Layer contact stacking between graphene-like BN and ultrathin Bi_(3)O_(4)Br was achieved with strong interaction. Dehalogenation is designed to harvest more visible light, and the ultrathin structure of Bi_(3)O_(4)Br is designed to accelerate charge transfer from inside to the surface. After graphene-like BN was engineered, photocatalytic performance greatly improved under visible light irradiation. Graphene-like BN can act as a surface electron-withdrawing center and adsorption center, facilitating molecular oxygen activation. O_(2)^(·-)was determined to be the main active species during the degradation process through analyses of electron spin resonance and XPS valence band spectra.展开更多
通过对角化364×364完全能量矩阵的理论方法,对掺杂在Bi_(4)Ge_(3)O_(12)晶体中的Er^(3+)的Stark能级和EPR参数进行了研究,同时,定量分析了高阶晶体场混合效应和J-J混合效应对EPR g因子的影响。研究结果表明:对Er^(3+)来说,最主要的...通过对角化364×364完全能量矩阵的理论方法,对掺杂在Bi_(4)Ge_(3)O_(12)晶体中的Er^(3+)的Stark能级和EPR参数进行了研究,同时,定量分析了高阶晶体场混合效应和J-J混合效应对EPR g因子的影响。研究结果表明:对Er^(3+)来说,最主要的J-J混合效应来源于多重态谱项2 K 15/2,其对EPR g因子的贡献约占2.5%,而最主要的高阶晶体场混合效应来源于第一激发多重态^(4)I_(13/2)和基态多重态^(4)I_(15/2)之间的晶体场混合,其对各向异性g因子中g⊥的贡献大致是g//的两倍(即g⊥约占0.21%,g//约占0.092%),其他更高阶的晶体场混合和J-J混合效应可以忽略不计。因此,对于Er^(3+)掺杂的络合物系统来说,只考虑基态多重态4 I 15/2对EPR g因子的贡献应该是一个很好的近似。展开更多
文摘Novel graphitic carbon nitride(g-C_(3)N_(4))nanosheet/Bi_(5)O_(7)Br/NH_(2)-MIL-88B(Fe)photocatalysts(denoted as GCN-NSh/Bi_(5)O_(7)Br/FeMOF,in which MOF is metal–organic framework)with double S-scheme heterojunctions were synthesized by a facile solvothermal route.The resultant materials were examined by X-ray photoelectron spectrometer(XPS),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDX),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),photoluminescence spectroscopy(PL),Fourier transform infrared spectroscopy(FT-IR),UV-Vis diffuse reflection spectroscopy(UV-vis DRS),photocurrent density,electrochemical impedance spectroscopy(EIS),and Brunauer–Emmett–Teller(BET)analyses.After the integration of Fe-MOF with GCN-NSh/Bi_(5)O_(7)Br,the removal constant of tetracycline over the optimal GCN-NSh/Bi_(5)O_(7)Br/Fe-MOF(15wt%)nanocomposite was promoted 33 times compared with that of the pristine GCN.The GCN-NSh/Bi_(5)O_(7)Br/Fe-MOF(15wt%)nanocomposite showed superior photoactivity to azithromycin,metronidazole,and cephalexin removal that was 36.4,20.2,and 14.6 times higher than that of pure GCN,respectively.Radical quenching tests showed that·O_(2)-and h+mainly contributed to the elimination reaction.In addition,the nanocomposite maintained excellent activity after 4 successive cycles.Based on the developed n–n heterojunctions among n-GCN-NSh,n-Bi_(5)O_(7)Br,and n-Fe-MOF semiconductors,the double S-scheme charge transfer mechanism was proposed for the destruction of the selected antibiotics.
基金financially supported by the Fundamental Research Funds for the Central Universities (No.30922010302)the Start-Up Grant from Nanjing University of Science and Technology (AE89991/397)。
文摘Novel graphene-like boron nitride(BN)/Bi_(3)O_(4)Br photocatalysts have been controllably synthesized through a facile solvothermal method for the first time. Layer contact stacking between graphene-like BN and ultrathin Bi_(3)O_(4)Br was achieved with strong interaction. Dehalogenation is designed to harvest more visible light, and the ultrathin structure of Bi_(3)O_(4)Br is designed to accelerate charge transfer from inside to the surface. After graphene-like BN was engineered, photocatalytic performance greatly improved under visible light irradiation. Graphene-like BN can act as a surface electron-withdrawing center and adsorption center, facilitating molecular oxygen activation. O_(2)^(·-)was determined to be the main active species during the degradation process through analyses of electron spin resonance and XPS valence band spectra.
文摘通过对角化364×364完全能量矩阵的理论方法,对掺杂在Bi_(4)Ge_(3)O_(12)晶体中的Er^(3+)的Stark能级和EPR参数进行了研究,同时,定量分析了高阶晶体场混合效应和J-J混合效应对EPR g因子的影响。研究结果表明:对Er^(3+)来说,最主要的J-J混合效应来源于多重态谱项2 K 15/2,其对EPR g因子的贡献约占2.5%,而最主要的高阶晶体场混合效应来源于第一激发多重态^(4)I_(13/2)和基态多重态^(4)I_(15/2)之间的晶体场混合,其对各向异性g因子中g⊥的贡献大致是g//的两倍(即g⊥约占0.21%,g//约占0.092%),其他更高阶的晶体场混合和J-J混合效应可以忽略不计。因此,对于Er^(3+)掺杂的络合物系统来说,只考虑基态多重态4 I 15/2对EPR g因子的贡献应该是一个很好的近似。
