Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields.In this study,we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al me...Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields.In this study,we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al metal oxides(represented as Zn2ZrxAl-MMO)in light of the structural topotactic transformation of Zn2ZrxAl-hydrotalcite precursors(Zn2ZrxAl-LDH).The resulting Zn2ZrxAl-MMO catalysts were employed in the conversion of ethanol to diethyl carbonate.The Zr^4+ ion content of the LDH precursor plays a key role in modulating the acid-base properties and determining catalytic performance:the Zn2Zr0.1Al-MMO sample exhibits the optimal catalytic behavior with a diethyl carbonate(DEC)yield of 42.1%,which is the highest reported for metal oxide catalysts.Structure-property correlation investigations revealed that the synergic catalysis between medium-strong basic sites and weak acid sites plays a predominant role in the catalytic behavior.Furthermore,in situ Fourier transform infrared measurements showed that the weak acidic site promotes activation adsorption of the reactant(urea)and the intermediate product(ethyl carbamate),while the medium-strong basic site accelerates ethanol activation.Moreover,the Zn2Zr0.1Al-MMO catalyst has the advantages of cost effectiveness,good stability,and reusability.Therefore,the acid-base bifunctional catalysts developed in this work can be employed as promising candidates in acid-base catalytic reactions such as ethanol conversion.展开更多
基金supported by the National Key R&D Program(2017YFA0206804)the National Natural Science Foundation of China(21871021,21521005)the Fundamental Research Funds for the Central Universities(buctylkxj01,XK1802-6)~~
文摘Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields.In this study,we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al metal oxides(represented as Zn2ZrxAl-MMO)in light of the structural topotactic transformation of Zn2ZrxAl-hydrotalcite precursors(Zn2ZrxAl-LDH).The resulting Zn2ZrxAl-MMO catalysts were employed in the conversion of ethanol to diethyl carbonate.The Zr^4+ ion content of the LDH precursor plays a key role in modulating the acid-base properties and determining catalytic performance:the Zn2Zr0.1Al-MMO sample exhibits the optimal catalytic behavior with a diethyl carbonate(DEC)yield of 42.1%,which is the highest reported for metal oxide catalysts.Structure-property correlation investigations revealed that the synergic catalysis between medium-strong basic sites and weak acid sites plays a predominant role in the catalytic behavior.Furthermore,in situ Fourier transform infrared measurements showed that the weak acidic site promotes activation adsorption of the reactant(urea)and the intermediate product(ethyl carbamate),while the medium-strong basic site accelerates ethanol activation.Moreover,the Zn2Zr0.1Al-MMO catalyst has the advantages of cost effectiveness,good stability,and reusability.Therefore,the acid-base bifunctional catalysts developed in this work can be employed as promising candidates in acid-base catalytic reactions such as ethanol conversion.
