Double-atom catalysts(DACs)have emerged as an enhanced platform of single-atom catalyst for promoting electrocatalytic CO_(2) reduction reaction(CO_(2) RR).Herein,we present a density-functional theory study on CO_(2)...Double-atom catalysts(DACs)have emerged as an enhanced platform of single-atom catalyst for promoting electrocatalytic CO_(2) reduction reaction(CO_(2) RR).Herein,we present a density-functional theory study on CO_(2) RR performance of seven C_(2) N-supported homo-and heteronuclear DACs,denoted as M_(2)@C_(2) N.Our results demonstrate that there exists substantial synergistic effect of dual-metal-atom N_(2) M_(2) N_(2) active site and C_(2) N matrix on O=C=O bond activation.The dual-atom M_(2) sites are able to drive CO_(2) RR beyond C1 products with low limiting potential(UL).Specifically,C_(2) H4 formation is preferred on FeM@C_(2) N(M=Fe,Co,Ni,Cu)versus CH4 formation on CuM@C_(2) N(M=Co,Ni,Cu).Furthermore,^(*)CO+^(*)CO cobinding strength can serve as a descriptor for CO_(2) RR activity for making C_(2) products such that the moderate binding results in the lowest UL.Remarkably,C-affinity matters most to C-C bond coupling and C_(2) H4 formation while both C-and O-affinity control CH4 formation.Our results provide theoretical insight into rational design of DACs for efficient CO_(2) RR.展开更多
Ternary multifunctional A<sub>1</sub>Zn<sub>y</sub>Zr<sub>z</sub>O<sub>n</sub> catalysts are prepared by introducing A-site transition metals with the redox capability i...Ternary multifunctional A<sub>1</sub>Zn<sub>y</sub>Zr<sub>z</sub>O<sub>n</sub> catalysts are prepared by introducing A-site transition metals with the redox capability into binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub>. Structure and morphology were investigated by means of XRD, BET and FESEM, respectively. Activity data showed that Cr addition exhibited obvious beneficial effect to promote isobutene production from direct conversion of bio-ethanol compared to other A-site metal dopants. A significant higher yield of isobutene over Cr-promoted Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> catalyst was also observed with respect to its binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> counterpart. The choice of A-site metal is of prime importance in the isobutene production, catalyzing mainly the ethanol dehydrogenation, meanwhile the appropriate addition of zinc on the catalyst surface is also essential for good isobutene yield.展开更多
In this study, the catalyst composition in binary ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst was initially evaluated and optimized for methanol steam reforming. Then different Na contents were lo...In this study, the catalyst composition in binary ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst was initially evaluated and optimized for methanol steam reforming. Then different Na contents were loaded by an incipient wetness impregnation method onto the optimized ZnAl catalyst. It was found that the activity was greatly enhanced by the modification of Na, which depended on the Na content in the catalyst. The methanol conversion was 96% on a 0.1 Na/0.4 ZnAl catalyst (GHSV = 14,040 h<sup>-</sup><sup>1</sup>, S/C = 1.4, 350°C), which was much higher with respect to a Na-free 0.4 ZnAl catalyst (74%). The remarkable improvement of activity was attributed to a weakening of the C-H bonds and clear of hydroxyl group by the Na dopant leading to an accelerated dehydrogenation of the reaction intermediates formed on ZnAl<sub>2</sub>O<sub>4</sub> spinel surface and thus the overall reaction.展开更多
基金supported by the National Natural Science Foundation of China(21673137)the Science and Technology Commission of Shanghai Municipality(16ZR1413900,18030501100)+1 种基金the support from the Program for Top Talents in Songjiang District of Shanghaithe support from the Talent Program of Shanghai University of Engineering Science。
文摘Double-atom catalysts(DACs)have emerged as an enhanced platform of single-atom catalyst for promoting electrocatalytic CO_(2) reduction reaction(CO_(2) RR).Herein,we present a density-functional theory study on CO_(2) RR performance of seven C_(2) N-supported homo-and heteronuclear DACs,denoted as M_(2)@C_(2) N.Our results demonstrate that there exists substantial synergistic effect of dual-metal-atom N_(2) M_(2) N_(2) active site and C_(2) N matrix on O=C=O bond activation.The dual-atom M_(2) sites are able to drive CO_(2) RR beyond C1 products with low limiting potential(UL).Specifically,C_(2) H4 formation is preferred on FeM@C_(2) N(M=Fe,Co,Ni,Cu)versus CH4 formation on CuM@C_(2) N(M=Co,Ni,Cu).Furthermore,^(*)CO+^(*)CO cobinding strength can serve as a descriptor for CO_(2) RR activity for making C_(2) products such that the moderate binding results in the lowest UL.Remarkably,C-affinity matters most to C-C bond coupling and C_(2) H4 formation while both C-and O-affinity control CH4 formation.Our results provide theoretical insight into rational design of DACs for efficient CO_(2) RR.
文摘Ternary multifunctional A<sub>1</sub>Zn<sub>y</sub>Zr<sub>z</sub>O<sub>n</sub> catalysts are prepared by introducing A-site transition metals with the redox capability into binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub>. Structure and morphology were investigated by means of XRD, BET and FESEM, respectively. Activity data showed that Cr addition exhibited obvious beneficial effect to promote isobutene production from direct conversion of bio-ethanol compared to other A-site metal dopants. A significant higher yield of isobutene over Cr-promoted Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> catalyst was also observed with respect to its binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> counterpart. The choice of A-site metal is of prime importance in the isobutene production, catalyzing mainly the ethanol dehydrogenation, meanwhile the appropriate addition of zinc on the catalyst surface is also essential for good isobutene yield.
文摘In this study, the catalyst composition in binary ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst was initially evaluated and optimized for methanol steam reforming. Then different Na contents were loaded by an incipient wetness impregnation method onto the optimized ZnAl catalyst. It was found that the activity was greatly enhanced by the modification of Na, which depended on the Na content in the catalyst. The methanol conversion was 96% on a 0.1 Na/0.4 ZnAl catalyst (GHSV = 14,040 h<sup>-</sup><sup>1</sup>, S/C = 1.4, 350°C), which was much higher with respect to a Na-free 0.4 ZnAl catalyst (74%). The remarkable improvement of activity was attributed to a weakening of the C-H bonds and clear of hydroxyl group by the Na dopant leading to an accelerated dehydrogenation of the reaction intermediates formed on ZnAl<sub>2</sub>O<sub>4</sub> spinel surface and thus the overall reaction.
