The utilization of perovskite oxide materials as catalysts for the photodegradation of organic pollutants in water is a promising and rapidly advancing field.In this study,a series of La_(1−x)Ba_(x)CoO_(3)(x=0.2,0.3,0...The utilization of perovskite oxide materials as catalysts for the photodegradation of organic pollutants in water is a promising and rapidly advancing field.In this study,a series of La_(1−x)Ba_(x)CoO_(3)(x=0.2,0.3,0.4,0.5,0.6)catalysts with varying Ba doping ratios were synthesized using the citric acid complexation-hydrothermal synthesis combined method for the degradation of phenol under visible light irradiation.Among the synthesized catalysts,La_(0.5)Ba_(0.5)CoO_(3) exhibited the highest photocatalytic activity.In addition,the photocatalytic mechanism for La_(0.5)Ba_(0.5)CoO_(3) perovskite degradation of phenol was also discussed.The synthesized catalysts were characterized using XRD,SEM,FT-IR,XPS,MPMS and other characterization techniques.The results revealed that the diffraction peak intensity of La_(1−x)Ba_(x)CoO_(3) increased with higher Ba doping ratios,and the La_(0.4)Ba_(0.6)CoO_(3) exhibited the strongest diffraction peaks.The catalyst particle sizes ranged from 10 to 50 nm,and the specific surface area decreased with increasing Ba content.Additionally,the paramagnetic properties of La_(0.5)Ba_(0.5)CoO_(3) were similar to that of La_(0.4)Ba_(0.6)CoO_(3).The experimental results suggested that the incorporation of Ba could significantly improve the catalytic performance of La_(1−x)Ba_(x)CoO_(3) perovskites,promote electron transfer and favor to the generation of hydroxyl radicals(•OH),leading to the efficiently degradation of phenol.展开更多
Lightweight and high-toughness carbon fiber/phenolic ablator(CFPA)is required as the Thermal Protection System(TPS)material of aerospace vehicles for next-generation space missions.To improve the ablative properties,s...Lightweight and high-toughness carbon fiber/phenolic ablator(CFPA)is required as the Thermal Protection System(TPS)material of aerospace vehicles for next-generation space missions.To improve the ablative properties,silica sol with good particle size distribution prepared using tetramethoxysilane(TMOS)was blended with natural rubber latex and deposited onto carbon fiber felt,which was then integrated with phenolic aerogel matrix,introducing nano-silica into the framework of CFPA.The modified CFPA with a low density of 0.28—0.31 g/cm3exhibits strain-in-fracture as high as 31.2%and thermal conductivity as low as 0.054 W/(m·K).Furthermore,a trace amount of nano-silica could effectively protect CFPA from erosion of oxidizing atmosphere in different high-temperature environments.The oxyacetylene ablation test of 3000°C for 20 s shows a mass ablation rate of 0.0225 g/s,a linear ablation rate of 0.209 mm/s for the modified CFPA,which are 9.64%and 24.82%lower than the unmodified one.Besides,the long-time butane ablation test of 1200°C for 200 s shows an insignificant recession with mass and linear ablation rate of 0.079 g/s and 0.039 mm/s,16.84%and 13.33%lower than the unmodified one.Meanwhile,the fixed thermocouple in the test also demonstrates a good thermal insulation performance with a low peak back-face temperature of 207.7°C,12.25%lower than the unmodified one.Therefore,the nano-silica modified CFPA with excellent overall performance presents promising prospects in high-temperature aerospace applications.展开更多
The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excel...The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excellent phenol hydrogenation activity(conversion 96.9%)at 160℃,3 MPa,which is higher than that of leaf shaped Co@NC-67L-450 catalyst(conversion 75.4%).We demonstrated Co_(3)O_(4)was reduced to the Co^(0)during the reaction.Moreover,CoNx species contribute to the superior hydrogenation activity of phenol.The Co-based catalysts can be easily recovered through the magnetic separation and performed the high stability.展开更多
为筛选出有效保留黑果花楸果脯酚类物质及抗氧化活性的干燥加工方法,分别采用热风干燥、微波-热风干燥、真空冷冻干燥3种干燥加工方式处理黑果花楸,测定其干燥后酚类物质含量、单体酚类物质的组成及抗氧化活性,并分析了黑果花楸果脯酚...为筛选出有效保留黑果花楸果脯酚类物质及抗氧化活性的干燥加工方法,分别采用热风干燥、微波-热风干燥、真空冷冻干燥3种干燥加工方式处理黑果花楸,测定其干燥后酚类物质含量、单体酚类物质的组成及抗氧化活性,并分析了黑果花楸果脯酚类物质与抗氧化活性之间的相关性。结果表明:经过干燥加工处理后黑果花楸果脯总酚含量和总黄酮含量显著下降,采用真空冷冻干燥二者保留率最高(总酚保留率为85.35%,总黄酮保留率为85.37%);抗氧化活性均有不同程度的下降,真空冷冻干燥组表现出最强的抗氧化能力(1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率为21.06%,2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)阳离子自由基清除率为82.19%,铁离子还原抗氧化能力为798μmol Trolox/100 g m_(d),羟基自由基清除率为69.68%)。经真空冷冻干燥处理后,黑果花楸果脯中白藜芦醇、阿魏酸、芥子酸、表儿茶素含量无显著变化,肉桂酸含量显著增加,其他各单体酚含量均显著降低。黑果花楸果脯的总酚含量、总黄酮含量与DPPH自由基清除率、ABTS阳离子自由基清除率、铁离子还原抗氧化能力之间呈显著正相关(P<0.05),与羟基自由基清除率的相关性不显著,黑果花楸果脯中主要起抗氧化作用的单体酚类物质为槲皮素、芦丁、咖啡酸、白藜芦醇。综上,真空冷冻干燥是一种有效保留黑果花楸中酚类物质及抗氧化活性的加工方式。展开更多
基金The Fundamental Research Program for Young Scientists of Shanxi Province(Project No.202103021223294)The Fundamental Research Program of Shanxi Province(Project No.202203021211203)+1 种基金The Start-up Fund for Doctorate Scientific Research Project of Taiyuan University of Science and Technology(Project No.20232124)The Innovation and Entrepreneurship Training Program for Undergraduate,Taiyuan University of Science and Technology(Project No.DCX2024162).
文摘The utilization of perovskite oxide materials as catalysts for the photodegradation of organic pollutants in water is a promising and rapidly advancing field.In this study,a series of La_(1−x)Ba_(x)CoO_(3)(x=0.2,0.3,0.4,0.5,0.6)catalysts with varying Ba doping ratios were synthesized using the citric acid complexation-hydrothermal synthesis combined method for the degradation of phenol under visible light irradiation.Among the synthesized catalysts,La_(0.5)Ba_(0.5)CoO_(3) exhibited the highest photocatalytic activity.In addition,the photocatalytic mechanism for La_(0.5)Ba_(0.5)CoO_(3) perovskite degradation of phenol was also discussed.The synthesized catalysts were characterized using XRD,SEM,FT-IR,XPS,MPMS and other characterization techniques.The results revealed that the diffraction peak intensity of La_(1−x)Ba_(x)CoO_(3) increased with higher Ba doping ratios,and the La_(0.4)Ba_(0.6)CoO_(3) exhibited the strongest diffraction peaks.The catalyst particle sizes ranged from 10 to 50 nm,and the specific surface area decreased with increasing Ba content.Additionally,the paramagnetic properties of La_(0.5)Ba_(0.5)CoO_(3) were similar to that of La_(0.4)Ba_(0.6)CoO_(3).The experimental results suggested that the incorporation of Ba could significantly improve the catalytic performance of La_(1−x)Ba_(x)CoO_(3) perovskites,promote electron transfer and favor to the generation of hydroxyl radicals(•OH),leading to the efficiently degradation of phenol.
基金partly supported by the National Natural Science Foundation of China(Grant Nos.22178107,U21A2060,22178116)Xinjiang Uygur Autonomous Region Key Research and Development Program(Grant No.2022B01030)Shanghai Pujiang Program(Grant No.21PJD019)。
文摘Lightweight and high-toughness carbon fiber/phenolic ablator(CFPA)is required as the Thermal Protection System(TPS)material of aerospace vehicles for next-generation space missions.To improve the ablative properties,silica sol with good particle size distribution prepared using tetramethoxysilane(TMOS)was blended with natural rubber latex and deposited onto carbon fiber felt,which was then integrated with phenolic aerogel matrix,introducing nano-silica into the framework of CFPA.The modified CFPA with a low density of 0.28—0.31 g/cm3exhibits strain-in-fracture as high as 31.2%and thermal conductivity as low as 0.054 W/(m·K).Furthermore,a trace amount of nano-silica could effectively protect CFPA from erosion of oxidizing atmosphere in different high-temperature environments.The oxyacetylene ablation test of 3000°C for 20 s shows a mass ablation rate of 0.0225 g/s,a linear ablation rate of 0.209 mm/s for the modified CFPA,which are 9.64%and 24.82%lower than the unmodified one.Besides,the long-time butane ablation test of 1200°C for 200 s shows an insignificant recession with mass and linear ablation rate of 0.079 g/s and 0.039 mm/s,16.84%and 13.33%lower than the unmodified one.Meanwhile,the fixed thermocouple in the test also demonstrates a good thermal insulation performance with a low peak back-face temperature of 207.7°C,12.25%lower than the unmodified one.Therefore,the nano-silica modified CFPA with excellent overall performance presents promising prospects in high-temperature aerospace applications.
基金The National Natural Science Foundation of China(22102194)The Science and Technology Plan of Gansu Province(20JR10RA044)The Youth Innovation Promotion Association of CAS(2022427).
文摘The Co@NC catalysts with different morphologies were prepared by two step process,solvent control growth and pyrolysis method.The polyhedral Co@NC-67P-450 catalyst has a relatively high CoNx content and exhibits excellent phenol hydrogenation activity(conversion 96.9%)at 160℃,3 MPa,which is higher than that of leaf shaped Co@NC-67L-450 catalyst(conversion 75.4%).We demonstrated Co_(3)O_(4)was reduced to the Co^(0)during the reaction.Moreover,CoNx species contribute to the superior hydrogenation activity of phenol.The Co-based catalysts can be easily recovered through the magnetic separation and performed the high stability.
文摘为筛选出有效保留黑果花楸果脯酚类物质及抗氧化活性的干燥加工方法,分别采用热风干燥、微波-热风干燥、真空冷冻干燥3种干燥加工方式处理黑果花楸,测定其干燥后酚类物质含量、单体酚类物质的组成及抗氧化活性,并分析了黑果花楸果脯酚类物质与抗氧化活性之间的相关性。结果表明:经过干燥加工处理后黑果花楸果脯总酚含量和总黄酮含量显著下降,采用真空冷冻干燥二者保留率最高(总酚保留率为85.35%,总黄酮保留率为85.37%);抗氧化活性均有不同程度的下降,真空冷冻干燥组表现出最强的抗氧化能力(1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率为21.06%,2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)阳离子自由基清除率为82.19%,铁离子还原抗氧化能力为798μmol Trolox/100 g m_(d),羟基自由基清除率为69.68%)。经真空冷冻干燥处理后,黑果花楸果脯中白藜芦醇、阿魏酸、芥子酸、表儿茶素含量无显著变化,肉桂酸含量显著增加,其他各单体酚含量均显著降低。黑果花楸果脯的总酚含量、总黄酮含量与DPPH自由基清除率、ABTS阳离子自由基清除率、铁离子还原抗氧化能力之间呈显著正相关(P<0.05),与羟基自由基清除率的相关性不显著,黑果花楸果脯中主要起抗氧化作用的单体酚类物质为槲皮素、芦丁、咖啡酸、白藜芦醇。综上,真空冷冻干燥是一种有效保留黑果花楸中酚类物质及抗氧化活性的加工方式。
