This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation o...This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.展开更多
Electronic structures of the Mn^2＋ ：CdMoO4 crystal axe studied within the framework of the fully relativistic self-consistent Dirac Slater theory, using a numerically discrete variation （DV-Xα） method. The calcul...Electronic structures of the Mn^2＋ ：CdMoO4 crystal axe studied within the framework of the fully relativistic self-consistent Dirac Slater theory, using a numerically discrete variation （DV-Xα） method. The calculated results indicate that the 3d states of Mn have donor energy level in the forbidden band of CdMoO4 crystal. The O^2- transition energy of O 2p→Mn 3d is 3.12eV under excitation corresponding electronic transition being O^2-＋Mn^2＋→↑hvex=3.12 eV O^-- ＋Mn^＋→↑hvem O^2-＋Mn^2＋. It is predicted that the wavelength of emission should be located in the range of the 500-600nm. Thus the 500-600mm emission bands peaking at 550nm （2.25eV） of CdMoO4 crystal under excitation may be related to the Mn-like dopant ion in CdMoO4 crystal.展开更多
To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination pr...To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination procedure.The crystal phases,morphologies,chemical compositions,textural structures,and optical properties of the as-prepared composites were characterized by the corresponding analytical techniques.The photocatalytic activities toward degradation of rhodamine B solution were evaluated under visible light irradiation.The results revealed that integrating CdMoO4 with g-C3N4 could remarkably improve the charge separation and photocatalytic activity,compared with those of pristine g-C3N4 and CdMoO4.This would be because the CdMoO4/g-C3N4 composites could facilitate the transfer and separation of the photoexcited electron-hole pairs,which was confirmed by electrochemical impedance spectroscopy,transient photocurrent responses,and photoluminescence measurements.Moreover,active species trapping experiments demonstrated that holes(h+)and superoxide radicals(?O2?)were the main active species during the photocatalytic reaction.A possible photocatalytic mechanism was proposed on the basis of the energy band structures determined by Mott-Schottky tests.This work would provide further insights into the rational fabrication of composites for organic contaminant removal.展开更多
分别以1 mL 1-正丁基-3-甲基咪唑氯盐([Bmim]Cl)(离子液体Ⅰ)和1 mL 14,-双(N-甲基咪唑)丁烷溴盐([C4(Mim)2][Br]2)(离子液体Ⅱ)为辅助剂,CdCl2与Na2MoO4在60℃下反应1 h制备了单分散性较好的圆球状和椭球状的CdMoO4,并利用X射线衍射仪...分别以1 mL 1-正丁基-3-甲基咪唑氯盐([Bmim]Cl)(离子液体Ⅰ)和1 mL 14,-双(N-甲基咪唑)丁烷溴盐([C4(Mim)2][Br]2)(离子液体Ⅱ)为辅助剂,CdCl2与Na2MoO4在60℃下反应1 h制备了单分散性较好的圆球状和椭球状的CdMoO4,并利用X射线衍射仪、扫描电子显微镜对产物的组成和形貌进行了表征。结果表明,在2种条件下制备的产物均为四方晶相的CdMoO4,但其大小有所差异。以紫外光灯为光源,2种不同离子液体合成的CdMoO4微球为光催化剂,对有机染料罗丹明B进行了光降解实验。研究发现,利用双阳离子液体合成的CdMoO4微椭球具有更高的光催化活性,经过60 min其光降解率达到了98.9%。展开更多
CdMoO4 nano-octahedra were grown in situ at room temperature by reverse-microemulsion.Energy evolution from this growth process was monitored using microcalorimetry.The microcalorimetric heat flow (MCHF) curve showed ...CdMoO4 nano-octahedra were grown in situ at room temperature by reverse-microemulsion.Energy evolution from this growth process was monitored using microcalorimetry.The microcalorimetric heat flow (MCHF) curve showed a characteristic endothermic peak for the initial reaction,and double discontinuous exothermic peaks for the subsequent crystal growth.Combined with complementary characterization techniques,the evolution of morphology and size of the CdMoO4 nano-octahedra were correlated with the MCHF peaks.Calculations based on the microcalorimetric results at 298.15 K provided rate constants of 7.56×10–5 s–1 for the reaction and nucleation process and 1.59×10–4 s–1 for the crystallization process.展开更多
Controllable synthesis of uniform and single-crystalline CdMoO4 nano-octahedra has been successfully realized at large-scale by a facile reverse-microemulsion route at room temperature. The structures, compositions an...Controllable synthesis of uniform and single-crystalline CdMoO4 nano-octahedra has been successfully realized at large-scale by a facile reverse-microemulsion route at room temperature. The structures, compositions and morphologies of the as-prepared products were characterized in detail by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), respectively. According to the thermochemical cycle, the relationship between the standard molar enthalpy of formation of nano-CdMoO4 and bulk CdMoO4 was proposed for the first time. In combination with micro-calorimetry, the standard molar enthalpies of formation at 298.15 K of as-ynthesized CdMoO4 nano-octahedra were ob-tained.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.22172144).
文摘This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.
文摘Electronic structures of the Mn^2＋ ：CdMoO4 crystal axe studied within the framework of the fully relativistic self-consistent Dirac Slater theory, using a numerically discrete variation （DV-Xα） method. The calculated results indicate that the 3d states of Mn have donor energy level in the forbidden band of CdMoO4 crystal. The O^2- transition energy of O 2p→Mn 3d is 3.12eV under excitation corresponding electronic transition being O^2-＋Mn^2＋→↑hvex=3.12 eV O^-- ＋Mn^＋→↑hvem O^2-＋Mn^2＋. It is predicted that the wavelength of emission should be located in the range of the 500-600nm. Thus the 500-600mm emission bands peaking at 550nm （2.25eV） of CdMoO4 crystal under excitation may be related to the Mn-like dopant ion in CdMoO4 crystal.
基金supported by the Open Project Program of Hubei Key Laboratory of Animal Nutrition and Feed Science,Wuhan Polytechnic University(No.201808)Hubei Important Project of Technological Innovation(2018ABA094)~~
文摘To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination procedure.The crystal phases,morphologies,chemical compositions,textural structures,and optical properties of the as-prepared composites were characterized by the corresponding analytical techniques.The photocatalytic activities toward degradation of rhodamine B solution were evaluated under visible light irradiation.The results revealed that integrating CdMoO4 with g-C3N4 could remarkably improve the charge separation and photocatalytic activity,compared with those of pristine g-C3N4 and CdMoO4.This would be because the CdMoO4/g-C3N4 composites could facilitate the transfer and separation of the photoexcited electron-hole pairs,which was confirmed by electrochemical impedance spectroscopy,transient photocurrent responses,and photoluminescence measurements.Moreover,active species trapping experiments demonstrated that holes(h+)and superoxide radicals(?O2?)were the main active species during the photocatalytic reaction.A possible photocatalytic mechanism was proposed on the basis of the energy band structures determined by Mott-Schottky tests.This work would provide further insights into the rational fabrication of composites for organic contaminant removal.
文摘分别以1 mL 1-正丁基-3-甲基咪唑氯盐([Bmim]Cl)(离子液体Ⅰ)和1 mL 14,-双(N-甲基咪唑)丁烷溴盐([C4(Mim)2][Br]2)(离子液体Ⅱ)为辅助剂,CdCl2与Na2MoO4在60℃下反应1 h制备了单分散性较好的圆球状和椭球状的CdMoO4,并利用X射线衍射仪、扫描电子显微镜对产物的组成和形貌进行了表征。结果表明,在2种条件下制备的产物均为四方晶相的CdMoO4,但其大小有所差异。以紫外光灯为光源,2种不同离子液体合成的CdMoO4微球为光催化剂,对有机染料罗丹明B进行了光降解实验。研究发现,利用双阳离子液体合成的CdMoO4微椭球具有更高的光催化活性,经过60 min其光降解率达到了98.9%。
基金supported by the National Natural Science Foundation of China (20963001)the Natural Science Foundation of Guang Zhuang Autonomous Region (0575030,0832078 and 0991085)the Innovation Project of Guangxi University for Nationalities (gxun-chx2009082)
文摘CdMoO4 nano-octahedra were grown in situ at room temperature by reverse-microemulsion.Energy evolution from this growth process was monitored using microcalorimetry.The microcalorimetric heat flow (MCHF) curve showed a characteristic endothermic peak for the initial reaction,and double discontinuous exothermic peaks for the subsequent crystal growth.Combined with complementary characterization techniques,the evolution of morphology and size of the CdMoO4 nano-octahedra were correlated with the MCHF peaks.Calculations based on the microcalorimetric results at 298.15 K provided rate constants of 7.56×10–5 s–1 for the reaction and nucleation process and 1.59×10–4 s–1 for the crystallization process.
基金supported by the National Natural Science Foundation of China (20963001, 21273050)Guangxi Natural Science Foundation(0991001z)
文摘Controllable synthesis of uniform and single-crystalline CdMoO4 nano-octahedra has been successfully realized at large-scale by a facile reverse-microemulsion route at room temperature. The structures, compositions and morphologies of the as-prepared products were characterized in detail by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), respectively. According to the thermochemical cycle, the relationship between the standard molar enthalpy of formation of nano-CdMoO4 and bulk CdMoO4 was proposed for the first time. In combination with micro-calorimetry, the standard molar enthalpies of formation at 298.15 K of as-ynthesized CdMoO4 nano-octahedra were ob-tained.
