PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing ...PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.展开更多
为改善乳清分离蛋白凝胶性能并提高其营养特性,将氧化魔芋葡甘露聚糖(oxidized konjac glucomannan,OKGM)与乳清分离蛋白(whey protein isolate,WPI)混合制备复合凝胶,研究OKGM添加量(1%、1.5%、2%、2.5%、3%)对WPI凝胶的持水性、质构...为改善乳清分离蛋白凝胶性能并提高其营养特性,将氧化魔芋葡甘露聚糖(oxidized konjac glucomannan,OKGM)与乳清分离蛋白(whey protein isolate,WPI)混合制备复合凝胶,研究OKGM添加量(1%、1.5%、2%、2.5%、3%)对WPI凝胶的持水性、质构、流变特性、热稳定性的影响,并对复合凝胶的形成机理进行了初步探讨。结果表明,OKGM的添加使复合凝胶的持水性(65.59%~93.42%)显著高于纯蛋白凝胶(53.58%);质构分析发现OKGM添加量为2%时凝胶的硬度、胶着性、咀嚼性达到最大值;流变分析发现复合凝胶是弱凝胶,对高频率和高温具有更高的依赖性;热重分析表明OKGM添加量≤1.5%时,OKGM-WPI复合凝胶的热稳定性均高于纯乳清分离蛋白凝胶;表面疏水性和游离巯基分析发现OKGM的添加降低了表面疏水性和游离巯基含量,说明OKGM与WPI发生交联和聚集形成复合凝胶;扫描电镜观察发现复合凝胶结构更为致密、有序。综上,可以通过添加OKGM改善WPI凝胶性能及稳定性。展开更多
文摘PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.
文摘为改善乳清分离蛋白凝胶性能并提高其营养特性,将氧化魔芋葡甘露聚糖(oxidized konjac glucomannan,OKGM)与乳清分离蛋白(whey protein isolate,WPI)混合制备复合凝胶,研究OKGM添加量(1%、1.5%、2%、2.5%、3%)对WPI凝胶的持水性、质构、流变特性、热稳定性的影响,并对复合凝胶的形成机理进行了初步探讨。结果表明,OKGM的添加使复合凝胶的持水性(65.59%~93.42%)显著高于纯蛋白凝胶(53.58%);质构分析发现OKGM添加量为2%时凝胶的硬度、胶着性、咀嚼性达到最大值;流变分析发现复合凝胶是弱凝胶,对高频率和高温具有更高的依赖性;热重分析表明OKGM添加量≤1.5%时,OKGM-WPI复合凝胶的热稳定性均高于纯乳清分离蛋白凝胶;表面疏水性和游离巯基分析发现OKGM的添加降低了表面疏水性和游离巯基含量,说明OKGM与WPI发生交联和聚集形成复合凝胶;扫描电镜观察发现复合凝胶结构更为致密、有序。综上,可以通过添加OKGM改善WPI凝胶性能及稳定性。
