An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant s...An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant surface nickel and cobalt components as active sites led to strong Ni-Co interaction with charge transfer from nickel to cobalt.Notably,electron-enriched Coδ-species participated in efficient chemisorption and activation of CO_(2)to generate monodentate carbonate.Simultaneously,plentiful available Ni0sites facilitated H2dissociation,thus CO_(2)and H2were smoothly activated at zones of Coδ-species and Ni0,respectively.Detailed in situ DRIFTS,quasi situ XPS,TPSR,and DFT calculations substantiated a new formate evolution mechanism via monodentate carbonate instead of traditional bidentate carbonate based on synergistic catalysis of Coδ-species and Ni0.The zonal activation of CO_(2)and H2by tuning electron behaviors of double-center catalysts can boost heterogeneous catalytic hydrogenation performance.展开更多
Two types of palladiu m(Ⅱ)-based metallacalixarenes[ML]^(2+)and[ML_(2)]^(2+)have been synthesized through coordination-driven self-assembly from a series of flexible pyridine-bridged diimidazole ligands[2,6-bis((1 H-...Two types of palladiu m(Ⅱ)-based metallacalixarenes[ML]^(2+)and[ML_(2)]^(2+)have been synthesized through coordination-driven self-assembly from a series of flexible pyridine-bridged diimidazole ligands[2,6-bis((1 H-imidazol-1-yl)methyl)pyridine(L^(1)),2,6-bis((1 H-benzo[d]imidazol-1-yl)methyl)pyridine(L^(2)),2,6-bis((1 H-naphtho[2,3-d]imidazol-1-yl)methyl)pyridine(L^(3))],with palladium(II)-based building blocks[Pd(BF_(4))_(2)(M^(1)-BF_4)and(tmeda)Pd(NO_(3))_(2)(M^(2)-NO_(3))(tmeda=N,N,N',N'-tetramethyl-ethylenediamine)].All complexes were characterized by NMR spectroscopy(^(1)H NMR and^(13)C NMR),mass spectrometry(CSIMS,ESI-HRMS)and elemental analysis.The single crystal X-ray diffraction analysis of[M^(1)L^(2)_2](NO_(3))_(2),[M^(1)L^(3)_2](NO_(3))_(2),[M^(1)L^(3)_2](PF_6)_2 and[M~2 L^(3)](NO_(3))_(2)further confirmed the uniquely single bowl-shape and double bowl-shape structures.The anion binding properties within the metallacalixarenes as receptors were also investigated by NMR titration experiments in DMSO.展开更多
基金funded by the Science and Technology Project of Southwest United Graduate School of Yunnan Province(No.202302AQ370002)the National Natural Science Foundation of China(No.22206066)。
文摘An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant surface nickel and cobalt components as active sites led to strong Ni-Co interaction with charge transfer from nickel to cobalt.Notably,electron-enriched Coδ-species participated in efficient chemisorption and activation of CO_(2)to generate monodentate carbonate.Simultaneously,plentiful available Ni0sites facilitated H2dissociation,thus CO_(2)and H2were smoothly activated at zones of Coδ-species and Ni0,respectively.Detailed in situ DRIFTS,quasi situ XPS,TPSR,and DFT calculations substantiated a new formate evolution mechanism via monodentate carbonate instead of traditional bidentate carbonate based on synergistic catalysis of Coδ-species and Ni0.The zonal activation of CO_(2)and H2by tuning electron behaviors of double-center catalysts can boost heterogeneous catalytic hydrogenation performance.
基金supported by the National Natural Science Foundation of China(No.21906002)Beijing Municipal Science and Technology Project(No.KM202010005010)+2 种基金Beijing Municipal Natural Science Fund Project of Beijing Education Committee science and technology project key project(No.KZ201710005001)Beijing municipal high level innovative team building program(No.IDHT20180504)Beijing Outstanding Young Scientist Program(No.BJJWZYJH01201910005017)。
文摘Two types of palladiu m(Ⅱ)-based metallacalixarenes[ML]^(2+)and[ML_(2)]^(2+)have been synthesized through coordination-driven self-assembly from a series of flexible pyridine-bridged diimidazole ligands[2,6-bis((1 H-imidazol-1-yl)methyl)pyridine(L^(1)),2,6-bis((1 H-benzo[d]imidazol-1-yl)methyl)pyridine(L^(2)),2,6-bis((1 H-naphtho[2,3-d]imidazol-1-yl)methyl)pyridine(L^(3))],with palladium(II)-based building blocks[Pd(BF_(4))_(2)(M^(1)-BF_4)and(tmeda)Pd(NO_(3))_(2)(M^(2)-NO_(3))(tmeda=N,N,N',N'-tetramethyl-ethylenediamine)].All complexes were characterized by NMR spectroscopy(^(1)H NMR and^(13)C NMR),mass spectrometry(CSIMS,ESI-HRMS)and elemental analysis.The single crystal X-ray diffraction analysis of[M^(1)L^(2)_2](NO_(3))_(2),[M^(1)L^(3)_2](NO_(3))_(2),[M^(1)L^(3)_2](PF_6)_2 and[M~2 L^(3)](NO_(3))_(2)further confirmed the uniquely single bowl-shape and double bowl-shape structures.The anion binding properties within the metallacalixarenes as receptors were also investigated by NMR titration experiments in DMSO.
