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
Lead-free glass-ceramic composites in barium sodium niobate silica system with Gd2O3 addition were synthesized through melt-casting fol-lowed by controlled crystallization technique. Crystallization and dielectric pro...Lead-free glass-ceramic composites in barium sodium niobate silica system with Gd2O3 addition were synthesized through melt-casting fol-lowed by controlled crystallization technique. Crystallization and dielectric properties of the Gd2O3 adding glass-ceramic composites were investigated. With the increase in the concentration of Gd2O3, the glass transition temperature and the crystallization temperature of the pre-cursor glass shift towards the higher temperature. The crystallization behavior that occurred during the heat treatment procedure leads to the enhancement of dielectric constant. All the three compositions of glass-ceramic composites exhibit ferroelectricity when tested at room tem-perature. Both the values of the remanent polarization and coercive field are enhanced regularly with the gradual increase in the concentration of Gd2O3 additive under the same testing field.展开更多
Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.
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.
基金supported by the National Natural Science Foundation of China (No. 51107005)
文摘Lead-free glass-ceramic composites in barium sodium niobate silica system with Gd2O3 addition were synthesized through melt-casting fol-lowed by controlled crystallization technique. Crystallization and dielectric properties of the Gd2O3 adding glass-ceramic composites were investigated. With the increase in the concentration of Gd2O3, the glass transition temperature and the crystallization temperature of the pre-cursor glass shift towards the higher temperature. The crystallization behavior that occurred during the heat treatment procedure leads to the enhancement of dielectric constant. All the three compositions of glass-ceramic composites exhibit ferroelectricity when tested at room tem-perature. Both the values of the remanent polarization and coercive field are enhanced regularly with the gradual increase in the concentration of Gd2O3 additive under the same testing field.
文摘Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.
