Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspa...Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspartic acid(ASP)and lauric acid(La),were explored as corrosion inhibitors to in situ intercalate into the Zn Al-layered double hydroxides(Zn Al-LDHs)on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and the corrosion resistance of these two LDHs coating before and after corrosion experiment were investigated.It is found that both the two kinds of Zn Al-LDHs films consist of uniform and dense layered nanosheets(NSs),and the NSs of ZnAl-ASP-LDHs films grow vertically,but those of ZnAl-La-LDHs films exhibit a staggered tilted structure.The corrosion current density of the two Zn Al-LDHs films are two orders of magnitude lower than that of Mg alloy substrate.After one week’s immersion in NaCl solution,the NSs structure of two kind of ZnAl-LDHs films still remains the uniform and densely coverage on Mg alloy.Owing to the larger d(003)spacing,the ZnAl-La-LDHs have better ability to absorb Cl-and release interlayer anions than Zn Al-ASP-LDHs.These results indicate that the Zn Al-LDHs films intercalated with organic anions,specially La anions,can significantly improve the corrosion resistance of Mg alloy.展开更多
ZnO-Al2O3 derived from layered double hydroxides （ZnAl-LDH） was successfully applied for dispersion of Pd-Ag bimetallic catalysts for the selective hydrogenation of acetylene to ethylene and the Pd-Ag/ZnO-Al2O3 cata...ZnO-Al2O3 derived from layered double hydroxides （ZnAl-LDH） was successfully applied for dispersion of Pd-Ag bimetallic catalysts for the selective hydrogenation of acetylene to ethylene and the Pd-Ag/ZnO-Al2O3 cata- lyst showed the best catalytic performance among the prepared samples. It was found that the catalyst carrier of ZnO-Al2O3 metal-oxides derived form ZnAl-LDH could significantly suppress the over-hydrogenation of acetylene to obtain the relatively higher selectivity of ethylene. The introduction of Ag restricted efficiently the formation of coke because of the oligomerization reaction, which was further evidenced by thermal gravimetric analysis. The se- lectivity towards ethylene was in the order of Pd-Ag/ZnO-Al2O3〉Pd/ZnO-Al2O3〉Pd-Ag/Al2O3〉Pd/Al2O3 at a high conversion level. As the thermal gravimetric and differential temperature analysis （TG-DTA） revealed, Pd-Ag intermetallic catalyst on the ZnO-Al2O3 support showed less coke formation.展开更多
基金supported by the Natural Science Foundation of Chongqing(cstc2019jcyjmsxm X0566,cstc2018jcyj AX0450,cstc2018jcyj A2923,cstc2017jcyj AX0393)Projects of President Foundation of Chongqing University(2019CDXZWL002)+3 种基金Fundamental Research Funds for the Central Universities(2019CDXYWL0029,2018CDJDWL0011,106112017CDJQJ328839,106112016CDJZR288805)Science and Technology Research Program of Chongqing Municipal Education Commission(KJKJQN201800102,KJQN201800619,KJ1703042)NSFC(11544010,11374359,11304405 and 1155305)the Sharing Fund of Large-scale Equipment of Chongqing University(201903150094)
文摘Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspartic acid(ASP)and lauric acid(La),were explored as corrosion inhibitors to in situ intercalate into the Zn Al-layered double hydroxides(Zn Al-LDHs)on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and the corrosion resistance of these two LDHs coating before and after corrosion experiment were investigated.It is found that both the two kinds of Zn Al-LDHs films consist of uniform and dense layered nanosheets(NSs),and the NSs of ZnAl-ASP-LDHs films grow vertically,but those of ZnAl-La-LDHs films exhibit a staggered tilted structure.The corrosion current density of the two Zn Al-LDHs films are two orders of magnitude lower than that of Mg alloy substrate.After one week’s immersion in NaCl solution,the NSs structure of two kind of ZnAl-LDHs films still remains the uniform and densely coverage on Mg alloy.Owing to the larger d(003)spacing,the ZnAl-La-LDHs have better ability to absorb Cl-and release interlayer anions than Zn Al-ASP-LDHs.These results indicate that the Zn Al-LDHs films intercalated with organic anions,specially La anions,can significantly improve the corrosion resistance of Mg alloy.
基金This work was supported by the National Natural Science Foundation of China （21476145）. The authors thank Y. F. Liu, Z. L. Guo, L. M. Li, and C. Y. ki for useful discussion and helps. X. P. Gao thanks the China Cheng Da Engineering Co., Ltd for scholarship.
文摘ZnO-Al2O3 derived from layered double hydroxides （ZnAl-LDH） was successfully applied for dispersion of Pd-Ag bimetallic catalysts for the selective hydrogenation of acetylene to ethylene and the Pd-Ag/ZnO-Al2O3 cata- lyst showed the best catalytic performance among the prepared samples. It was found that the catalyst carrier of ZnO-Al2O3 metal-oxides derived form ZnAl-LDH could significantly suppress the over-hydrogenation of acetylene to obtain the relatively higher selectivity of ethylene. The introduction of Ag restricted efficiently the formation of coke because of the oligomerization reaction, which was further evidenced by thermal gravimetric analysis. The se- lectivity towards ethylene was in the order of Pd-Ag/ZnO-Al2O3〉Pd/ZnO-Al2O3〉Pd-Ag/Al2O3〉Pd/Al2O3 at a high conversion level. As the thermal gravimetric and differential temperature analysis （TG-DTA） revealed, Pd-Ag intermetallic catalyst on the ZnO-Al2O3 support showed less coke formation.
