The current research focused on adjusting the low hydration activity of the metallurgical slag by phase reconstruction technique. Boron oxide was used as a phase regulator to improve the amorphous phase composition of...The current research focused on adjusting the low hydration activity of the metallurgical slag by phase reconstruction technique. Boron oxide was used as a phase regulator to improve the amorphous phase composition of the manganese slag, consequently enhancing its hydraulic activity. The effects of boron oxide dosage and calcination temperature on the manganese slag amorphous phase content were investigated. XRD and DTG were performed to analyze the hydration mechanism of the manganese slag powder and cement. Results show that, when boron oxide dosage is 15%, calcination temperature is 1 300℃, and holding time for 1 hour, the amorphous content of the modified manganese slag reaches 95% and its 28-day activity index reaches 8 1.7%. The manganese slag powder can then be used as cement or concrete admixtures for the building materials industry.展开更多
The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis process.The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2...The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis process.The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2 h in flowing argon atmosphere to get the Al2OC product.The results indicate that the addition of B203 promotes the formation of Al2OC,which is dependent on the addition of B2 O3,and the Al2 OC content in the products increases with the increase of carbon.By systematically exploring the ratio of active carbon,alumina and boron oxide,the best formulation and the corresponding reaction mechanism were determined.展开更多
Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribut...Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribution (PSD), diffuse reflectance spectra (DRS), and Brunauer-Emmett-Teller (BET). The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B (ARB). The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3+ and Ce^4+, and the atomic ratio of Ce^3+/Ce^4+ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range (〈526 nm). As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels (Ce/Ti=2.0). The particles size ranged from 122 to 255 nm with a domain at 168 nm (39.4%). The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 (a standard TiO2 powder). The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.展开更多
Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using...Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using spark plasma sintering(SPS).This study examines the effect of varying the amount of toughened phase BNMR on the density,mechanical properties,dielectric constant,and thermal conductivity of BNMR/Al_(2)O_(3)composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated ceramics.The results showed that for a BNMR content of 5 wt%,BNMR/Al_(2)O_(3)composite ceramics displayed more enhanced characteristics than pure Al_(2)O_(3)ceramics.In particular,the relative density,hardness,fracture toughness,and bending strength were 99.95%±0.025%,34.11±1.5 GPa,5.42±0.21 MPa·m^(1/2),and 375±2.5 MPa,respectively.These values represent increases of 0.76%,70%,35%,and 25%,respectively,compared with the corresponding values for pure Al_(2)O_(3)ceramics.Furthermore,during the SPS process,BNMRs are subjected to high temperatures and pressures,resulting in the bending and deformation of the Al_(2)O_(3)matrix;this leads to the formation of special thermal pathways within it.The dielectric constant of the composite ceramics decreased by 25.6%,whereas the thermal conductivity increased by 45.6%compared with that of the pure Al_(2)O_(3)ceramics.The results of this study provide valuable insights into ways of enhancing the performance of Al_(2)O_(3)-based ceramic substrates by incorporating novel BNMRs as a second phase.These improvements are significant for potential applications in circuit substrates and related fields that require high-performance materials with improved mechanical properties and thermal conductivities.展开更多
Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing...Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing reaction temperature and NaO H-to-CBM mass ratio increases B2O3 extraction efficiency. There are two stages for the B2O3 extracting process: 0–20 min is the first stage, which is rapid; 20–50 min is the second stage, which is slower than the first stage. The overall extracting process follows the shrinking core model, and the first and second stages are determined to obey the surface chemical reaction model and the diffusion through the products layer model,respectively. The activation energies of the first and second stages are calculated to be 41.74 and 15.43 kJ·mol-1,respectively. The B2O3 extracting kinetics equations of the first and second stages are also obtained.展开更多
The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconi...The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconium diboride were heated at 700℃,900℃,1100℃and 1300℃for 3 h in air,respectively.The results show that Zr02 and B203(Ⅰ)are generated from the chemosynthetic zirconium diboride oxidized at 700℃for 3 h or the fused zirconium diboride oxidized at 800℃for 24 h;B203(Ⅰ)dissolves into water and then H3B03 crystallizes.展开更多
Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s body.In this work,we developed a new doping source-graphite and solid boron oxide powders to synth...Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s body.In this work,we developed a new doping source-graphite and solid boron oxide powders to synthesize BDD film with microwave plasma chemical vapor deposition,so as to avoid using toxic or corrosive dopants,such as boroethane and trimethylborate.The synthesized BDD film is pinhole free and with high doping density of 8.44×10^20 cm^-3 calculated from the Raman spectroscopy.Subsequently,Au nanospheres were decorated on the surface of BDD film to improve electrochemical performance of the BDD film.The Au nanoparticles modified BDD electrode demonstrates an excellent electrochemical response,a high sensitivity(in the range of 5μM-1 m M),and a low detection limit(~0.8μM)for detecting dopamine.展开更多
Ammonia borane(NH_(3)BH_(3))is a reducing agent,able to trap and convert carbon dioxide.In the present work,we used a reactive solid consisting of a mixture of 90 wt.%of NH_(3)BH_(3)and 10 wt.%of palladium chloride,be...Ammonia borane(NH_(3)BH_(3))is a reducing agent,able to trap and convert carbon dioxide.In the present work,we used a reactive solid consisting of a mixture of 90 wt.%of NH_(3)BH_(3)and 10 wt.%of palladium chloride,because the mixture reacts in a fast and exothermic way while releasing H2 and generating catalytic Pd0.We took advantage of such reactivity to trap and convert CO_(2)(7 bar),knowing besides that Pd0 is a CO_(2)hydrogenation catalyst.The operation(i.e.stage 1)was effective:BNH polymers,and B−O,C=O,C−O,and C−H bonds(like in BOCH_(3)and BOOCH groups)were identified.We then(in stage 2)pyrolyzed the as-obtained solid at 1250℃ and washed it with water.In doing so,we isolated cyclotriboric acid H_(3)B3O6(stemming from B2O3 formed at 1250℃),hexagonal boron nitride,and graphitic carbon.In conclusion,the stage 1 showed that CO_(2)can be‘trapped’and converted,resulting in the formation of BOCH_(3)and BOOCH groups(possible sources of methanol and formic acid),and the stage 2 showed that CO_(2)transforms into graphitic carbon.展开更多
Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in catalysis.The material engineering of van der Waals heterojunction(vdWsH)based on t...Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in catalysis.The material engineering of van der Waals heterojunction(vdWsH)based on two-dimensional(2D)materials would be a potential way to optimize the as-prepared extrinsic physicochemical characteristics.However,it was still an almost uncultivated land waiting for exploration in catalysis.Herein,we introduced the inert h-boron nitride(h-BN)in non-metal reduced graphene oxide(GN)catalysts and constructed BN-GN vdWsH.The theoretical calculation demonstrated that the h-BN can effectively modify the electronic properties of graphene.With the introduction of h-BN,the BN-GN vdWsH can obviously enhance the catalytic activity of Li-CO_(2) battery.The existence of BN-GN vdWsH can reduce the overpotential more than 700 mV compared with reduced graphene oxide during the CO_(2) reduction reaction(CO_(2)RR)and CO_(2) evolution reaction(CO_(2)ER),and it extended cyclic stability more than three times,which was one structure design made it work as a high efficient electrocatalyst,catalytic materials.展开更多
Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for CaF2.The e...Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for CaF2.The effects of B2O3 and CaF2 on the melting properties of this system were investigated.The melting temperatures of fluxes including softening temperature (Ts), hemispherical temperature (Th), and flow temperature (Tf) were measured using the hemisphere method.The results indicate that the fluxing effect of B2O3is more significant than that of CaF2 .When the addition amount of B2O3 (mass percent) exceeds 6% , the melting temperatures of fluxes including Ts , Th and Tf are decreased lower than 1 300℃.The basicity of fluxes has a significant effect on the melting temperature , and the melting temperatures of the fluxes increase with the increase of fluxes basicity.However , when B2O3 is used as fluxing agent , the melting temperature changes little with the basicity increasing from 2.5 to 5.0. These characteristics are suitable for steelmaking process.Moreover , Fe2O3 has an important fluxing effect on this CaO-based steelmaking fluxes.This indicates that the fluxes system is suitable for steelmaking process.展开更多
B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting te...B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags (the mass ratio of CaO/SiO2 is 3--4) and the high basicity slags (the mass ratio of CaO/SiO2 is 5--8.75) were investigated. The slag melting temperature was meas- ured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and A1203. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted by B2 03, the melting temperature can be decreased remarkably. Espe- cially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in the range of 1.1--4.0 and 5.25--8. 0, respectively, the slag melting temperature is lower than 1 300 ℃. Therefore, the 132 03-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultra low melting temperature.展开更多
The effects of testing solutions and conditions on hydroxyapatite(HAp)formation as a means of in vitro bioactivity evaluation of B2O3 containing 45S5 bioactive glasses were systematically investigated.Four glass sampl...The effects of testing solutions and conditions on hydroxyapatite(HAp)formation as a means of in vitro bioactivity evaluation of B2O3 containing 45S5 bioactive glasses were systematically investigated.Four glass samples prepared by the traditional melt and quench process,where SiO2 in 45S5 was gradually replaced by B2O3(up to 30%),were studied.Two solutions:the simulated body fluid(SBF)and K2HPO4 solutions were used as the medium for evaluating in vitro bioactivity through the formation of HAp on glass surface as a function of time.It was found that addition of boron oxide delayed the HAp formation in both SBF and K2HPO4 solutions,while the reaction between glass and the K2HPO4 solution is much faster as compared to SBF.In addition to the composition and medium effects,we also studied whether the solution treatments(e.g.,adjusting to maintain a pH of 7.4,refreshing solution at certain time interval,and no disturbance during immersion)affect HAp formation.Fourier transform infrared spectrometer(FTIR)equipped with an attenuated total reflection(ATR)sampling technique and scanning electron microscopy(SEM)were conducted to identify HAp formation on glass powder surfaces and to observe HAp morphologies,respectively.The results show that refreshing solution every 24 h produced the fastest HAp formation for low boron-containing samples when SBF was used as testing solution,while no significant differences were observed when K2HPO4 solution was used.This study thus suggests the testing solutions and conditions play an important role on the in vitro bioactivity testing results and should be carefully considered when study materials with varying bioactivities.展开更多
The effects of minor alloying elements(antimony,boron) on the recrystallization and oxidation of Mn-containing interstitial free(IF) steels were investigated using confocal scanning laser microscope(CSLM) under ...The effects of minor alloying elements(antimony,boron) on the recrystallization and oxidation of Mn-containing interstitial free(IF) steels were investigated using confocal scanning laser microscope(CSLM) under controlled atmosphere of 95% Ar and 5% H2(volume percent) at different temperatures.The results indicated that oxidation and recrystallization were primarily controlled by the grain boundaries,which moved due to release of the stored energy or acted as the fast path diffusion of alloying elements.It was found that the addition of antimony suppressed both surface oxidation and internal oxidation,whereas boron addition accelerated surface oxidation but decreased internal oxidation.The reasons caused were that the alloying elements of antimony or boron were known to segregate on the surfaces or grain boundaries to occupy the surface adsorption sites,which were expected to be less catalytic than bare iron on the transportation of alloying elements.The recrystallization was also retarded through adding minor antimony and boron elements.The oxidation kinetics of formation of grain boundary oxides were studied through calculating the areas along grain boundaries,and it was found that the areas parabolically increased with increasing time.展开更多
基金Funded by the National High-tech Research and Development Prograrn of China(863 Program)(No.2012AA06A112)the National Natural Science Foundation of China(No.51162004)the Guangxi Science and Technology Development Plan(Nos.12118014-3D,12118019-2-15,1348011-2)
文摘The current research focused on adjusting the low hydration activity of the metallurgical slag by phase reconstruction technique. Boron oxide was used as a phase regulator to improve the amorphous phase composition of the manganese slag, consequently enhancing its hydraulic activity. The effects of boron oxide dosage and calcination temperature on the manganese slag amorphous phase content were investigated. XRD and DTG were performed to analyze the hydration mechanism of the manganese slag powder and cement. Results show that, when boron oxide dosage is 15%, calcination temperature is 1 300℃, and holding time for 1 hour, the amorphous content of the modified manganese slag reaches 95% and its 28-day activity index reaches 8 1.7%. The manganese slag powder can then be used as cement or concrete admixtures for the building materials industry.
基金financially supported by National Natural Science Foundation of China ( 51274156)
文摘The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis process.The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2 h in flowing argon atmosphere to get the Al2OC product.The results indicate that the addition of B203 promotes the formation of Al2OC,which is dependent on the addition of B2 O3,and the Al2 OC content in the products increases with the increase of carbon.By systematically exploring the ratio of active carbon,alumina and boron oxide,the best formulation and the corresponding reaction mechanism were determined.
基金Project supported by the National Natural Science Foundation of China (No. 20277010)
文摘Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribution (PSD), diffuse reflectance spectra (DRS), and Brunauer-Emmett-Teller (BET). The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B (ARB). The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3+ and Ce^4+, and the atomic ratio of Ce^3+/Ce^4+ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range (〈526 nm). As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels (Ce/Ti=2.0). The particles size ranged from 122 to 255 nm with a domain at 168 nm (39.4%). The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 (a standard TiO2 powder). The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.
基金the financial support from National Natural Science Foundation of China(No.52262010)the Guangxi Natural Science Foundation of China(No.2023GXNSFAA026384)the Guilin Scientific Research and Technology Development Program(No.2020011203-3).
文摘Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using spark plasma sintering(SPS).This study examines the effect of varying the amount of toughened phase BNMR on the density,mechanical properties,dielectric constant,and thermal conductivity of BNMR/Al_(2)O_(3)composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated ceramics.The results showed that for a BNMR content of 5 wt%,BNMR/Al_(2)O_(3)composite ceramics displayed more enhanced characteristics than pure Al_(2)O_(3)ceramics.In particular,the relative density,hardness,fracture toughness,and bending strength were 99.95%±0.025%,34.11±1.5 GPa,5.42±0.21 MPa·m^(1/2),and 375±2.5 MPa,respectively.These values represent increases of 0.76%,70%,35%,and 25%,respectively,compared with the corresponding values for pure Al_(2)O_(3)ceramics.Furthermore,during the SPS process,BNMRs are subjected to high temperatures and pressures,resulting in the bending and deformation of the Al_(2)O_(3)matrix;this leads to the formation of special thermal pathways within it.The dielectric constant of the composite ceramics decreased by 25.6%,whereas the thermal conductivity increased by 45.6%compared with that of the pure Al_(2)O_(3)ceramics.The results of this study provide valuable insights into ways of enhancing the performance of Al_(2)O_(3)-based ceramic substrates by incorporating novel BNMRs as a second phase.These improvements are significant for potential applications in circuit substrates and related fields that require high-performance materials with improved mechanical properties and thermal conductivities.
基金financially supported by the National Natural Science Foundation of China(No.51204037)
文摘Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing reaction temperature and NaO H-to-CBM mass ratio increases B2O3 extraction efficiency. There are two stages for the B2O3 extracting process: 0–20 min is the first stage, which is rapid; 20–50 min is the second stage, which is slower than the first stage. The overall extracting process follows the shrinking core model, and the first and second stages are determined to obey the surface chemical reaction model and the diffusion through the products layer model,respectively. The activation energies of the first and second stages are calculated to be 41.74 and 15.43 kJ·mol-1,respectively. The B2O3 extracting kinetics equations of the first and second stages are also obtained.
文摘The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconium diboride were heated at 700℃,900℃,1100℃and 1300℃for 3 h in air,respectively.The results show that Zr02 and B203(Ⅰ)are generated from the chemosynthetic zirconium diboride oxidized at 700℃for 3 h or the fused zirconium diboride oxidized at 800℃for 24 h;B203(Ⅰ)dissolves into water and then H3B03 crystallizes.
基金financially supported by the National Science Fund for Distinguished Young Scholars(No.51625201)the National Natural Science Foundation of China No.51,702,066+2 种基金the National Key Research and Development Program of China(No.2016YFE0201600)the Key Laboratory of Micro-systems and Micro-structures Manufacturing,Ministry of Education,Harbin Institute of Technology(No.2016KM001)the Innovative research group of NSFC11421091。
文摘Boron doped diamond(BDD)electrode is a promising electrochemical material for detecting dopamine level in the human’s body.In this work,we developed a new doping source-graphite and solid boron oxide powders to synthesize BDD film with microwave plasma chemical vapor deposition,so as to avoid using toxic or corrosive dopants,such as boroethane and trimethylborate.The synthesized BDD film is pinhole free and with high doping density of 8.44×10^20 cm^-3 calculated from the Raman spectroscopy.Subsequently,Au nanospheres were decorated on the surface of BDD film to improve electrochemical performance of the BDD film.The Au nanoparticles modified BDD electrode demonstrates an excellent electrochemical response,a high sensitivity(in the range of 5μM-1 m M),and a low detection limit(~0.8μM)for detecting dopamine.
基金supported by TUBITAK(Project No.218M181)and CAMPUS FRANCE PHC BOSPHORUS(Project No.42161TB).CACM.and U.B.D.want to acknowledge the CONACyT(Mexican National Council for Science and Technology)for the scholarship of CA.CM(2017-2021).
文摘Ammonia borane(NH_(3)BH_(3))is a reducing agent,able to trap and convert carbon dioxide.In the present work,we used a reactive solid consisting of a mixture of 90 wt.%of NH_(3)BH_(3)and 10 wt.%of palladium chloride,because the mixture reacts in a fast and exothermic way while releasing H2 and generating catalytic Pd0.We took advantage of such reactivity to trap and convert CO_(2)(7 bar),knowing besides that Pd0 is a CO_(2)hydrogenation catalyst.The operation(i.e.stage 1)was effective:BNH polymers,and B−O,C=O,C−O,and C−H bonds(like in BOCH_(3)and BOOCH groups)were identified.We then(in stage 2)pyrolyzed the as-obtained solid at 1250℃ and washed it with water.In doing so,we isolated cyclotriboric acid H_(3)B3O6(stemming from B2O3 formed at 1250℃),hexagonal boron nitride,and graphitic carbon.In conclusion,the stage 1 showed that CO_(2)can be‘trapped’and converted,resulting in the formation of BOCH_(3)and BOOCH groups(possible sources of methanol and formic acid),and the stage 2 showed that CO_(2)transforms into graphitic carbon.
基金supported by the National Natural Science Foundations of China(Nos:21771024 and 21871028)。
文摘Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in catalysis.The material engineering of van der Waals heterojunction(vdWsH)based on two-dimensional(2D)materials would be a potential way to optimize the as-prepared extrinsic physicochemical characteristics.However,it was still an almost uncultivated land waiting for exploration in catalysis.Herein,we introduced the inert h-boron nitride(h-BN)in non-metal reduced graphene oxide(GN)catalysts and constructed BN-GN vdWsH.The theoretical calculation demonstrated that the h-BN can effectively modify the electronic properties of graphene.With the introduction of h-BN,the BN-GN vdWsH can obviously enhance the catalytic activity of Li-CO_(2) battery.The existence of BN-GN vdWsH can reduce the overpotential more than 700 mV compared with reduced graphene oxide during the CO_(2) reduction reaction(CO_(2)RR)and CO_(2) evolution reaction(CO_(2)ER),and it extended cyclic stability more than three times,which was one structure design made it work as a high efficient electrocatalyst,catalytic materials.
基金Item Sponsored by National Natural Science Foundation of China ( 51174099 )Natural Science Foundation of Jiangsu Province of China ( BK2010355 )National Science Foundation for Post-Doctoral Scientists of China ( 20100471382 )
文摘Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for CaF2.The effects of B2O3 and CaF2 on the melting properties of this system were investigated.The melting temperatures of fluxes including softening temperature (Ts), hemispherical temperature (Th), and flow temperature (Tf) were measured using the hemisphere method.The results indicate that the fluxing effect of B2O3is more significant than that of CaF2 .When the addition amount of B2O3 (mass percent) exceeds 6% , the melting temperatures of fluxes including Ts , Th and Tf are decreased lower than 1 300℃.The basicity of fluxes has a significant effect on the melting temperature , and the melting temperatures of the fluxes increase with the increase of fluxes basicity.However , when B2O3 is used as fluxing agent , the melting temperature changes little with the basicity increasing from 2.5 to 5.0. These characteristics are suitable for steelmaking process.Moreover , Fe2O3 has an important fluxing effect on this CaO-based steelmaking fluxes.This indicates that the fluxes system is suitable for steelmaking process.
基金Item Sponsored by National High Technology Research and Development Program(863 Program)of China(2007AA03Z548)Natural Science Foundation of Jiangsu Province of China(BK2010355)
文摘B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags (the mass ratio of CaO/SiO2 is 3--4) and the high basicity slags (the mass ratio of CaO/SiO2 is 5--8.75) were investigated. The slag melting temperature was meas- ured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and A1203. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted by B2 03, the melting temperature can be decreased remarkably. Espe- cially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in the range of 1.1--4.0 and 5.25--8. 0, respectively, the slag melting temperature is lower than 1 300 ℃. Therefore, the 132 03-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultra low melting temperature.
基金support of the NSF Ceramics program(project#1508001)support of the NSF REU program(project#1461048)。
文摘The effects of testing solutions and conditions on hydroxyapatite(HAp)formation as a means of in vitro bioactivity evaluation of B2O3 containing 45S5 bioactive glasses were systematically investigated.Four glass samples prepared by the traditional melt and quench process,where SiO2 in 45S5 was gradually replaced by B2O3(up to 30%),were studied.Two solutions:the simulated body fluid(SBF)and K2HPO4 solutions were used as the medium for evaluating in vitro bioactivity through the formation of HAp on glass surface as a function of time.It was found that addition of boron oxide delayed the HAp formation in both SBF and K2HPO4 solutions,while the reaction between glass and the K2HPO4 solution is much faster as compared to SBF.In addition to the composition and medium effects,we also studied whether the solution treatments(e.g.,adjusting to maintain a pH of 7.4,refreshing solution at certain time interval,and no disturbance during immersion)affect HAp formation.Fourier transform infrared spectrometer(FTIR)equipped with an attenuated total reflection(ATR)sampling technique and scanning electron microscopy(SEM)were conducted to identify HAp formation on glass powder surfaces and to observe HAp morphologies,respectively.The results show that refreshing solution every 24 h produced the fastest HAp formation for low boron-containing samples when SBF was used as testing solution,while no significant differences were observed when K2HPO4 solution was used.This study thus suggests the testing solutions and conditions play an important role on the in vitro bioactivity testing results and should be carefully considered when study materials with varying bioactivities.
基金Item Sponsored by National Natural Science Foundation of China(50902003,51172003)National Key Technology Research and Development Program in 12th Five-Year Plan of China(2010BAE00316,2011BAB02B05)
文摘The effects of minor alloying elements(antimony,boron) on the recrystallization and oxidation of Mn-containing interstitial free(IF) steels were investigated using confocal scanning laser microscope(CSLM) under controlled atmosphere of 95% Ar and 5% H2(volume percent) at different temperatures.The results indicated that oxidation and recrystallization were primarily controlled by the grain boundaries,which moved due to release of the stored energy or acted as the fast path diffusion of alloying elements.It was found that the addition of antimony suppressed both surface oxidation and internal oxidation,whereas boron addition accelerated surface oxidation but decreased internal oxidation.The reasons caused were that the alloying elements of antimony or boron were known to segregate on the surfaces or grain boundaries to occupy the surface adsorption sites,which were expected to be less catalytic than bare iron on the transportation of alloying elements.The recrystallization was also retarded through adding minor antimony and boron elements.The oxidation kinetics of formation of grain boundary oxides were studied through calculating the areas along grain boundaries,and it was found that the areas parabolically increased with increasing time.