In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can r...In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can reduce silver ions to generate crystalline silver nanoparticles(Ag NPs)of good dispersion and uniformity on the alumina surface,leading to the formation of Ag/γ-Al_(2)O_(3)catalysts in a green manner without traditional chemical reductants.Ag/γ-Al_(2)O_(3)exhibited good catalytic activity and stability in CO oxidation reactions,and the activity increased with increase in the Ag content.For catalysts with more than 2 wt%Ag,100%CO conversion can be achieved at 300°C.The catalytic activity of the Ag/γ-Al_(2)O_(3)catalysts is also closely related to the size of theγ-alumina,where Ag/nano-γ-Al_(2)O_(3)catalysts demonstrate better performance than Ag/micro-γ-Al_(2)O_(3)catalysts with the same Ag content.In addition,the catalytic properties of plasma-generated Ag/nano-γ-Al_(2)O_(3)(Ag/γ-Al_(2)O_(3)-P)catalysts were compared with those of Ag/nano-γ-Al_(2)O_(3)catalysts prepared by the traditional calcination approach(Ag/γ-Al_(2)O_(3)-C),with the plasma-generated samples demonstrating better overall performance.This simple,rapid and green plasma process is considered to be applicable for the synthesis of diverse noble metal-based catalysts.展开更多
Al 合金-Al_2O_3陶瓷粒子铸造复合材料是由硬质 Al_2O_3粒子在 Al 合金基体上均匀分散而构成.这种复合材料既有较高的硬度又有良好的塑性.尤其是与铝合金相比,其耐磨性有成倍提高.因而,这种材料可望用作耐磨、制动、防弹及遮蔽材料.由于...Al 合金-Al_2O_3陶瓷粒子铸造复合材料是由硬质 Al_2O_3粒子在 Al 合金基体上均匀分散而构成.这种复合材料既有较高的硬度又有良好的塑性.尤其是与铝合金相比,其耐磨性有成倍提高.因而,这种材料可望用作耐磨、制动、防弹及遮蔽材料.由于 Al 合金液与 Al_3O_3陶瓷粒子的润湿性很差,两者的比重也有较大差异,因此Al_2O_3粒子在 Al 合金液中受到很大斥力,极易聚合沉降.改善 Al_2O_3粒子与金属液润湿性的措施通常有下列四个方面:(1)颗粒表面包覆金属;(2)向金属液中加入合金元素;(3)粒子预处理;(4)超声波振动熔体。至于制备工艺,常见的有下列三种:(1)喷入法.利用喷枪,以惰性气体作载体。展开更多
基金financial support from National Natural Science Foundation of China(Nos.52004102 and 22078125)Postdoctoral Science Foundation of China(No.2021M690068)+2 种基金Fundamental Research Funds for the Central Universities(Nos.JUSRP221018 and JUSRP622038)Key Laboratory of Green Cleaning Technology and Detergent of Zhejiang Province(No.Q202204)Open Project of Key Laboratory of Green Chemical Engineering Process of Ministry of Education(No.GCP202112)。
文摘In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can reduce silver ions to generate crystalline silver nanoparticles(Ag NPs)of good dispersion and uniformity on the alumina surface,leading to the formation of Ag/γ-Al_(2)O_(3)catalysts in a green manner without traditional chemical reductants.Ag/γ-Al_(2)O_(3)exhibited good catalytic activity and stability in CO oxidation reactions,and the activity increased with increase in the Ag content.For catalysts with more than 2 wt%Ag,100%CO conversion can be achieved at 300°C.The catalytic activity of the Ag/γ-Al_(2)O_(3)catalysts is also closely related to the size of theγ-alumina,where Ag/nano-γ-Al_(2)O_(3)catalysts demonstrate better performance than Ag/micro-γ-Al_(2)O_(3)catalysts with the same Ag content.In addition,the catalytic properties of plasma-generated Ag/nano-γ-Al_(2)O_(3)(Ag/γ-Al_(2)O_(3)-P)catalysts were compared with those of Ag/nano-γ-Al_(2)O_(3)catalysts prepared by the traditional calcination approach(Ag/γ-Al_(2)O_(3)-C),with the plasma-generated samples demonstrating better overall performance.This simple,rapid and green plasma process is considered to be applicable for the synthesis of diverse noble metal-based catalysts.
文摘Al 合金-Al_2O_3陶瓷粒子铸造复合材料是由硬质 Al_2O_3粒子在 Al 合金基体上均匀分散而构成.这种复合材料既有较高的硬度又有良好的塑性.尤其是与铝合金相比,其耐磨性有成倍提高.因而,这种材料可望用作耐磨、制动、防弹及遮蔽材料.由于 Al 合金液与 Al_3O_3陶瓷粒子的润湿性很差,两者的比重也有较大差异,因此Al_2O_3粒子在 Al 合金液中受到很大斥力,极易聚合沉降.改善 Al_2O_3粒子与金属液润湿性的措施通常有下列四个方面:(1)颗粒表面包覆金属;(2)向金属液中加入合金元素;(3)粒子预处理;(4)超声波振动熔体。至于制备工艺,常见的有下列三种:(1)喷入法.利用喷枪,以惰性气体作载体。
