Electrocatalytic CO2 reduction(CO2 ER)into formate is a desirable route to achieve efficient transformation of CO2 to value-added chemicals,however,it still suffers from limited catalytic activity and poor selectivity...Electrocatalytic CO2 reduction(CO2 ER)into formate is a desirable route to achieve efficient transformation of CO2 to value-added chemicals,however,it still suffers from limited catalytic activity and poor selectivity.Herein,we develop a hybrid electrocatalyst composed of bismuth and bismuth oxide nanoparticles(NPs)supported on nitrogen-doped reduced graphene oxide(Bi/Bi2 O3/NrGO)nanosheets prepared by a combined hydrothermal with calcination treatment.Thanks to the combination of undercoordinated sites and strong synergistic effect between Bi and Bi2 O3,Bi/Bi2 O3/NrGO-700 hybrid displays a promoted CO2 ER catalytic performance and selectivity for formate production,as featured by a small onset potential of-0.5 V,a high current density of-18 mA/cm2,the maximum Faradaic efficiency of85%at-0.9 V,and a low Tafel slope of 166 mV/dec.Experimental results reveal that the higher CO2 ER performance of Bi/Bi2 O3/NrGO-700 than that of Bi NPs supported on NrGO(Bi/NrGO)can be due to the partial reduction of Bi2 O3 NPs into Bi,which significantly increases undercoordinated active sites on Bi NPs surface,thus boosting its CO2 ER performance.Furthermore,a two-electrode device with Ir/C anode and Bi/Bi2 O3/NrGO-700 cathode could be integrated with two alkaline batteries or a planar solar cell to achieve highly active water splitting and CO2 ER.展开更多
Ce3+ doped Bi2O3 hollow needle-shape with enhanced visible-light photocatalytic activity was successfully prepared via the method of chemical precipitation using Bi(NO3)·5H2O and Ce(NO3)3·6H2O as the source ...Ce3+ doped Bi2O3 hollow needle-shape with enhanced visible-light photocatalytic activity was successfully prepared via the method of chemical precipitation using Bi(NO3)·5H2O and Ce(NO3)3·6H2O as the source of bismuth and cerium, HNO3 as solvent and NaOH as precipitants, respectively and after calcination at 500 ℃ for 2 h. The morphology and elemental composition,crystal form,purity and specific surface area of the hollow needle Bi2O3 were characterized by SEM-EDS, XRD, BET and FT-IR. The photocatalytic properties of the as-obtained samples were measured by UV-vis diffuse reflection spectroscopy and photochemical reactor. As a result, the obtained Bi2O3 hollow needle-shape doped with 5 wt% Ce shows good morphology, α-phase, stronger absorbent for visible light and good photocatalytic property. Under the simulated visible light of 300 W, the photodegradation rate of tetracycline over HNBCe can reach to 89.1%,which is higher than that of commercial Bi2O3 nanoparticles and Bi2O3 hollow needle-shape.展开更多
A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is a...A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is assigned to monoclinic and tetragonal mix-crystal phase. Fibers lengths can reach several micrometers and diameters range from 0.5 μm to 3 μm. Compared with pure TiO2 and Bi2O3, TiO2/Bi2O3 samples display better absorption in visible light region. Photocatalytic activity was evaluated by degradation of MB under visible light irradiation. TiO2/Bi2O3 microfibers exhibite much higher activity than pure TiO2 and Bi2O3, and 22.84%TiO2/Bi2O3 can achieve the decomposition of about 95%MB, which is attributed to synergistic effects of the strong visible-light absorption of TiO2/Bi2O3 microfibers and the heterojunction formed between TiO2 and Bi2O3.展开更多
The 40Bi2O3-30B2O3-(30-x)ZnO-xSrO (x=0-15mol%,BBZSr) glass system was prepared by the conventional melt quenching method.The effect of SrO addition on structure,thermal properties,chemical stability and sealing perfor...The 40Bi2O3-30B2O3-(30-x)ZnO-xSrO (x=0-15mol%,BBZSr) glass system was prepared by the conventional melt quenching method.The effect of SrO addition on structure,thermal properties,chemical stability and sealing performance of BBZSr glass were investigated thoroughly.The experimental results show that the total proportions of [BO3] group and [BO4] group decrease and the vibrations of [BiO3] group and [BiO6] group become weaker with the increase of SrO addition content,suggesting the glass network structure is strengthened owing to the SrO addition.Hence,both the thermal and chemical stability were significantly improved as the SrO content was increased.When the SrO content increased from 0 to 15mol%,the glass transition temperature and softening temperature slightly increased from 380 to 388 ℃ and from 392.7 to 402.2 ℃,respectively,meanwhile the coefficient of thermal expansion also increased from 10.49×10^-6 to 11.16×10^-6/℃ (30-300 ℃).The BBZSr glass with 15mol% SrO exhibited excellent comprehensive properties with low glass transition temperature(384.9 ℃),low softening temperature(400.3 ℃),high coefficient of thermal expansion (11.14×10^-6 ℃,30-300 ℃),good thermal and chemical stability.Besides,the glass had the good wetting behavior and sealing performance for Al-50%Si alloy.展开更多
A bismuth oxide(Bi_2O_3)-dispersed carboxylated nitrile butadiene rubber(XNBR) flexible film was prepared as a flexible lead-free material for gamma ray(c-ray)attenuation.However,obtaining a uniform and stable dispers...A bismuth oxide(Bi_2O_3)-dispersed carboxylated nitrile butadiene rubber(XNBR) flexible film was prepared as a flexible lead-free material for gamma ray(c-ray)attenuation.However,obtaining a uniform and stable dispersion of Bi_2O_3 in carboxylated nitrile butadiene rubber latex(XNBRL) is a challenge due to sedimentation induced by the remarkable density differences.Here,this challenge was approached by reducing the Bi_2O-3 particle radius,increasing the viscosity of the latex,and adding a dispersant.The experimental results confirmed that Bi2 O3 was well dispersed in the XNBRL in the concentration range of 30–70 wt%.The mechanical properties demonstrated that the Bi_2O_3/XNBR flexible films had a good resistance to oil,acid,alkali,and hot air.The linear attenuation coefficients of the Bi_2O_3/XNBR flexible films obtained from the experiments were in good agreement with the calculated values.The attenuation efficiencies of the Bi_2O_3/XNBR flexible films with different thicknesses and Bi_2O_3 contents were investigated for a few different γ-ray energies.These results showed that the Bi_2O_3/XNBRflexible films have wide application prospects for low-energy γ-ray attenuation.展开更多
基金support of the Natural Science Foundation of Zhejiang Province(No.LR16E080003)support of National Natural Science Foundation of China(Nos.21922811,51702284,21878270)+2 种基金Zhejiang Provincial Natural Science Foundation of China(No.LR19B060002)the Fundamental Research Funds for the Central Universitiesthe Startup Foundation for Hundred-Talent Program of Zhejiang University。
摘要Electrocatalytic CO2 reduction(CO2 ER)into formate is a desirable route to achieve efficient transformation of CO2 to value-added chemicals,however,it still suffers from limited catalytic activity and poor selectivity.Herein,we develop a hybrid electrocatalyst composed of bismuth and bismuth oxide nanoparticles(NPs)supported on nitrogen-doped reduced graphene oxide(Bi/Bi2 O3/NrGO)nanosheets prepared by a combined hydrothermal with calcination treatment.Thanks to the combination of undercoordinated sites and strong synergistic effect between Bi and Bi2 O3,Bi/Bi2 O3/NrGO-700 hybrid displays a promoted CO2 ER catalytic performance and selectivity for formate production,as featured by a small onset potential of-0.5 V,a high current density of-18 mA/cm2,the maximum Faradaic efficiency of85%at-0.9 V,and a low Tafel slope of 166 mV/dec.Experimental results reveal that the higher CO2 ER performance of Bi/Bi2 O3/NrGO-700 than that of Bi NPs supported on NrGO(Bi/NrGO)can be due to the partial reduction of Bi2 O3 NPs into Bi,which significantly increases undercoordinated active sites on Bi NPs surface,thus boosting its CO2 ER performance.Furthermore,a two-electrode device with Ir/C anode and Bi/Bi2 O3/NrGO-700 cathode could be integrated with two alkaline batteries or a planar solar cell to achieve highly active water splitting and CO2 ER.
基金Project supported by the Capacity Building Program of Shanghai Local Universities(12160503600)
摘要Ce3+ doped Bi2O3 hollow needle-shape with enhanced visible-light photocatalytic activity was successfully prepared via the method of chemical precipitation using Bi(NO3)·5H2O and Ce(NO3)3·6H2O as the source of bismuth and cerium, HNO3 as solvent and NaOH as precipitants, respectively and after calcination at 500 ℃ for 2 h. The morphology and elemental composition,crystal form,purity and specific surface area of the hollow needle Bi2O3 were characterized by SEM-EDS, XRD, BET and FT-IR. The photocatalytic properties of the as-obtained samples were measured by UV-vis diffuse reflection spectroscopy and photochemical reactor. As a result, the obtained Bi2O3 hollow needle-shape doped with 5 wt% Ce shows good morphology, α-phase, stronger absorbent for visible light and good photocatalytic property. Under the simulated visible light of 300 W, the photodegradation rate of tetracycline over HNBCe can reach to 89.1%,which is higher than that of commercial Bi2O3 nanoparticles and Bi2O3 hollow needle-shape.
基金V. ACKNOWLEDGEMENTS This work was supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department (No.2013JK0690), and the Shaanxi Province Natural Science Foundation (No.2013JM2013), the National Natural Science Foundation of China (No.21203160), and the Special Research Fund of Xianyang Normal University (No. 11XSYK204).
摘要A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is assigned to monoclinic and tetragonal mix-crystal phase. Fibers lengths can reach several micrometers and diameters range from 0.5 μm to 3 μm. Compared with pure TiO2 and Bi2O3, TiO2/Bi2O3 samples display better absorption in visible light region. Photocatalytic activity was evaluated by degradation of MB under visible light irradiation. TiO2/Bi2O3 microfibers exhibite much higher activity than pure TiO2 and Bi2O3, and 22.84%TiO2/Bi2O3 can achieve the decomposition of about 95%MB, which is attributed to synergistic effects of the strong visible-light absorption of TiO2/Bi2O3 microfibers and the heterojunction formed between TiO2 and Bi2O3.
基金the Open Project Program of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(No.KLIFMD-2018-06)。
摘要The 40Bi2O3-30B2O3-(30-x)ZnO-xSrO (x=0-15mol%,BBZSr) glass system was prepared by the conventional melt quenching method.The effect of SrO addition on structure,thermal properties,chemical stability and sealing performance of BBZSr glass were investigated thoroughly.The experimental results show that the total proportions of [BO3] group and [BO4] group decrease and the vibrations of [BiO3] group and [BiO6] group become weaker with the increase of SrO addition content,suggesting the glass network structure is strengthened owing to the SrO addition.Hence,both the thermal and chemical stability were significantly improved as the SrO content was increased.When the SrO content increased from 0 to 15mol%,the glass transition temperature and softening temperature slightly increased from 380 to 388 ℃ and from 392.7 to 402.2 ℃,respectively,meanwhile the coefficient of thermal expansion also increased from 10.49×10^-6 to 11.16×10^-6/℃ (30-300 ℃).The BBZSr glass with 15mol% SrO exhibited excellent comprehensive properties with low glass transition temperature(384.9 ℃),low softening temperature(400.3 ℃),high coefficient of thermal expansion (11.14×10^-6 ℃,30-300 ℃),good thermal and chemical stability.Besides,the glass had the good wetting behavior and sealing performance for Al-50%Si alloy.
基金supported by the National Natural Science Foundation of China(No.11405149)the Military Technology Extension Project(No.JMZF201601)
摘要A bismuth oxide(Bi_2O_3)-dispersed carboxylated nitrile butadiene rubber(XNBR) flexible film was prepared as a flexible lead-free material for gamma ray(c-ray)attenuation.However,obtaining a uniform and stable dispersion of Bi_2O_3 in carboxylated nitrile butadiene rubber latex(XNBRL) is a challenge due to sedimentation induced by the remarkable density differences.Here,this challenge was approached by reducing the Bi_2O-3 particle radius,increasing the viscosity of the latex,and adding a dispersant.The experimental results confirmed that Bi2 O3 was well dispersed in the XNBRL in the concentration range of 30–70 wt%.The mechanical properties demonstrated that the Bi_2O_3/XNBR flexible films had a good resistance to oil,acid,alkali,and hot air.The linear attenuation coefficients of the Bi_2O_3/XNBR flexible films obtained from the experiments were in good agreement with the calculated values.The attenuation efficiencies of the Bi_2O_3/XNBR flexible films with different thicknesses and Bi_2O_3 contents were investigated for a few different γ-ray energies.These results showed that the Bi_2O_3/XNBRflexible films have wide application prospects for low-energy γ-ray attenuation.