Noble metal-based-bimetallic catalysts have been highly investigated and applied in wide applications including biomass transformation via regioselective C−O hydrogenolysis while further modification especially with n...Noble metal-based-bimetallic catalysts have been highly investigated and applied in wide applications including biomass transformation via regioselective C−O hydrogenolysis while further modification especially with noble metal is highly promising yet still under investigation.Herein,Ru was found as an effective modifier among the screened noble metals(Ru,Pt,Rh,Pd,Au,and Ag)for Ir-Fe/BN(Ir=5 wt%,Fe/Ir=0.25)catalyst in terminal C−O hydrogenolysis of 1,2-butanediol(1,2-BuD)to 2-butanol(2-BuOH).Only trace amount of Ru(up to 0.5 wt%)was effective in terms of high 2-BuOH selectivity(>60%)and activity(about twice).Larger amount of Ru species(3 wt%)highly enhanced the activity but gave low selectivity to 2-BuOH with by-products of terminal C−C bond scission.Optimized catalyst(Ru(0.5)-Ir-Fe/BN)was reusable at least 4 times and gave moderate 2-BuOH yield(47%)in hydrogenolysis of 1,2-BuD.The promoting effect of Ru addition(0.5 wt%)to Ir-Fe/BN on hydrogenolysis of various alcohols was also confirmed.Combining catalytic tests with various characterizations,the promotion mechanism of Ru species in trimetallic catalysts was clarified.The Ru species in Ru(0.5)-Ir-Fe/BN form alloy with Ir and are enriched at the interface with BN surface,and direct interaction between Ru and Fe was not necessary in Ru-Ir-Fe alloy.The interface of Ir and Fe on the surface of Ir-Fe alloy may work as active sites for 1,2-diols to secondary alcohols via direct C−O hydrogenolysis,in which Ru-modified Ir activates H_(2) to form hydride-like species.The activity of Ru species in C−C bond cleavage was highly suppressed due to the direct interaction with Ir species and less exposed to substrate.Larger loading amount of Ru species(3 wt%)led to the formation Ru-rich trimetallic alloy,which further works as active sites for C−C bond scission.展开更多
Melt-spun Nd9.5Fe81Zr3B6.5 ribbons were prepared by the melt-spinning technique. The phase evolution and magnetic properties were studied by X-ray diffraction, differential scanning calorimetry, transmission electron ...Melt-spun Nd9.5Fe81Zr3B6.5 ribbons were prepared by the melt-spinning technique. The phase evolution and magnetic properties were studied by X-ray diffraction, differential scanning calorimetry, transmission electron microscopy observations, and magnetization measurements. It is indicated that melt spinning at different wheel velocities caused the as-quenched ribbons to have distinctive structure. The phase transformation of the ribbons during annealing takes place in two steps： α-Fe transforms from the amorphous phase firstly, followed by formation of Nd2Fe14B phase. With increasing the initial quenching rate, the microstructure of optimally heat treated ribbons becomes coarser, which results in the weakening of the exchange coupling effect between the hard and soft phase. This leads to drastic deterioration of magnetic properties of annealed ribbons with increasing the initial quenching rate.展开更多
Glass from a light bulb is a waste product that cannot be utilised in a traditional way. This study looks into the possibilities of using lamp borosilicate glass powder as a cement replacing admixture in conventional ...Glass from a light bulb is a waste product that cannot be utilised in a traditional way. This study looks into the possibilities of using lamp borosilicate glass powder as a cement replacing admixture in conventional concrete. Experimental work provides preparation of standard concrete samples and sample testing after seven and 28-day ageing periods in standard conditions. The following glass materials were used for cement replacement： rough ground glass powder, glass dust from filters （both materials were obtained from a glass treatment plant） and additionally ground glass powder. The effect of glass powder on cement setting time was studied. The experimental results indicate that replacement of cement by rough glass powder decreases the compressive strength. Fine glass particles make it possible to replace up to 20% of cement without the loss in strength characteristics. Fine glass powder offers a long-term hardening effect. The best compressive strength results were achieved by using the glass that was additionally ground for 60 minutes. Glass dust obtained from filters shows a less significant effect. Summarising the research findings it may be concluded that ground borosilicate lamp glass may be successfully applied as a micro-filler for concrete as cement replacing material.展开更多
文摘Noble metal-based-bimetallic catalysts have been highly investigated and applied in wide applications including biomass transformation via regioselective C−O hydrogenolysis while further modification especially with noble metal is highly promising yet still under investigation.Herein,Ru was found as an effective modifier among the screened noble metals(Ru,Pt,Rh,Pd,Au,and Ag)for Ir-Fe/BN(Ir=5 wt%,Fe/Ir=0.25)catalyst in terminal C−O hydrogenolysis of 1,2-butanediol(1,2-BuD)to 2-butanol(2-BuOH).Only trace amount of Ru(up to 0.5 wt%)was effective in terms of high 2-BuOH selectivity(>60%)and activity(about twice).Larger amount of Ru species(3 wt%)highly enhanced the activity but gave low selectivity to 2-BuOH with by-products of terminal C−C bond scission.Optimized catalyst(Ru(0.5)-Ir-Fe/BN)was reusable at least 4 times and gave moderate 2-BuOH yield(47%)in hydrogenolysis of 1,2-BuD.The promoting effect of Ru addition(0.5 wt%)to Ir-Fe/BN on hydrogenolysis of various alcohols was also confirmed.Combining catalytic tests with various characterizations,the promotion mechanism of Ru species in trimetallic catalysts was clarified.The Ru species in Ru(0.5)-Ir-Fe/BN form alloy with Ir and are enriched at the interface with BN surface,and direct interaction between Ru and Fe was not necessary in Ru-Ir-Fe alloy.The interface of Ir and Fe on the surface of Ir-Fe alloy may work as active sites for 1,2-diols to secondary alcohols via direct C−O hydrogenolysis,in which Ru-modified Ir activates H_(2) to form hydride-like species.The activity of Ru species in C−C bond cleavage was highly suppressed due to the direct interaction with Ir species and less exposed to substrate.Larger loading amount of Ru species(3 wt%)led to the formation Ru-rich trimetallic alloy,which further works as active sites for C−C bond scission.
基金Projects(51201109,51001076)supported by the National Natural Science Foundation of ChinaProject(T201108)supported by Shenzhen Key Laboratory of Special Functional Materials,China
文摘Melt-spun Nd9.5Fe81Zr3B6.5 ribbons were prepared by the melt-spinning technique. The phase evolution and magnetic properties were studied by X-ray diffraction, differential scanning calorimetry, transmission electron microscopy observations, and magnetization measurements. It is indicated that melt spinning at different wheel velocities caused the as-quenched ribbons to have distinctive structure. The phase transformation of the ribbons during annealing takes place in two steps： α-Fe transforms from the amorphous phase firstly, followed by formation of Nd2Fe14B phase. With increasing the initial quenching rate, the microstructure of optimally heat treated ribbons becomes coarser, which results in the weakening of the exchange coupling effect between the hard and soft phase. This leads to drastic deterioration of magnetic properties of annealed ribbons with increasing the initial quenching rate.
文摘Glass from a light bulb is a waste product that cannot be utilised in a traditional way. This study looks into the possibilities of using lamp borosilicate glass powder as a cement replacing admixture in conventional concrete. Experimental work provides preparation of standard concrete samples and sample testing after seven and 28-day ageing periods in standard conditions. The following glass materials were used for cement replacement： rough ground glass powder, glass dust from filters （both materials were obtained from a glass treatment plant） and additionally ground glass powder. The effect of glass powder on cement setting time was studied. The experimental results indicate that replacement of cement by rough glass powder decreases the compressive strength. Fine glass particles make it possible to replace up to 20% of cement without the loss in strength characteristics. Fine glass powder offers a long-term hardening effect. The best compressive strength results were achieved by using the glass that was additionally ground for 60 minutes. Glass dust obtained from filters shows a less significant effect. Summarising the research findings it may be concluded that ground borosilicate lamp glass may be successfully applied as a micro-filler for concrete as cement replacing material.
