The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the divers...The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks(Ce-MOFs),this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X(X=-NH_(2),-OH,-Br,and-NO_(2))featuring rich solid-state FLPs for hydrogenation of unsaturated olefins.The-X functional group serves as a microenvironment,enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites.The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites(Ce-CUS,Lewis acid(LA))and adjacent Ce-OH(Lewis base(LB))sites within the MOFs,generating abundant solid-state FLP(Ce-CUS/Ce-OH)sites.Experimental results demonstrate that Ce-CUS and Ce-OH interact with theσandσ^(*)orbitals of H-H,and this"push-pull"synergy promotes heterolytic cleavage of the H-H bond.The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site,thereby increasing its strength and reducing the activation energy required for H_(2)heterolytic cleavage.Notably,at 100℃and 2 MPa H_(2),MOF-808-NH_(2)achieves complete conversion of styrene and dicyclopentadiene,significantly outperforming MOF-808.Based on in-situ analysis and density functional theory calculations,a plausible reaction mechanism is proposed.This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.展开更多
How to achieve low energy consumption and high degradation efficiency(DRE)under mild conditions is an important issue in the field of sulfur hexafluoride(SF_(6))treatment.In this work,a new route of SF_(6)degradation ...How to achieve low energy consumption and high degradation efficiency(DRE)under mild conditions is an important issue in the field of sulfur hexafluoride(SF_(6))treatment.In this work,a new route of SF_(6)degradation promoted by Ni-doped ceria(NiO-CeO_(2))in a packed bed dielectric barrier discharge(PB-DBD)was proposed.The effects of Ni/Ce molar ratio,input power,SF_(6)concentration and flow rate on the DRE of SF_(6)were investigated.Compared with DBD or CeO_(2)-DBD alone,the combination of DBD and NiO-CeO_(2)can significantly promote the SF_(6)degradation at lower input power.The experimental results show that when the dosage of catalyst 1.5NiO-CeO_(2)(Ni/Ce mole ratio is 1.5%)is 5 g,DBD input power is 50 W and SF_(6)(1.5%SF_(6)/98.5%Ar)flow rate is 100 ml·min-1,the highest DRE can reach 97.7%and the energy yield can reach 11.5 g·(kW·h)-1.Adjusting the catalyst dosage according to the flux of SF_(6)(e.g.,using 10 g catalyst to degrade SF_(6)with a concentration of 1.5%and a flow rate of 80 ml·min-1),the DRE of nearly 99%can be achieved for a long time,which is crucial for industrial application.The mechanism deduction shows that the rich surface and mesopores of the catalyst are beneficial to the adsorption of SF_(6)and intermediates,while the doping of Ni can significantly increase the content of oxygen vacancies to improve the degradation.Meanwhile,when NiO-CeO_(2)is activated by DBD,the free O·can further promote the degradation.It is this coupling effect that leads to the high efficiency and low energy consumption of SF_(6)degradation under mild conditions.It can be expected that this coupling technology route will have a good application prospect in the field of SF_(6)treatment.展开更多
文摘The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks(Ce-MOFs),this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X(X=-NH_(2),-OH,-Br,and-NO_(2))featuring rich solid-state FLPs for hydrogenation of unsaturated olefins.The-X functional group serves as a microenvironment,enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites.The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites(Ce-CUS,Lewis acid(LA))and adjacent Ce-OH(Lewis base(LB))sites within the MOFs,generating abundant solid-state FLP(Ce-CUS/Ce-OH)sites.Experimental results demonstrate that Ce-CUS and Ce-OH interact with theσandσ^(*)orbitals of H-H,and this"push-pull"synergy promotes heterolytic cleavage of the H-H bond.The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site,thereby increasing its strength and reducing the activation energy required for H_(2)heterolytic cleavage.Notably,at 100℃and 2 MPa H_(2),MOF-808-NH_(2)achieves complete conversion of styrene and dicyclopentadiene,significantly outperforming MOF-808.Based on in-situ analysis and density functional theory calculations,a plausible reaction mechanism is proposed.This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.
基金financial support from the National Natural Science Foundation of China(U23A20105).
文摘How to achieve low energy consumption and high degradation efficiency(DRE)under mild conditions is an important issue in the field of sulfur hexafluoride(SF_(6))treatment.In this work,a new route of SF_(6)degradation promoted by Ni-doped ceria(NiO-CeO_(2))in a packed bed dielectric barrier discharge(PB-DBD)was proposed.The effects of Ni/Ce molar ratio,input power,SF_(6)concentration and flow rate on the DRE of SF_(6)were investigated.Compared with DBD or CeO_(2)-DBD alone,the combination of DBD and NiO-CeO_(2)can significantly promote the SF_(6)degradation at lower input power.The experimental results show that when the dosage of catalyst 1.5NiO-CeO_(2)(Ni/Ce mole ratio is 1.5%)is 5 g,DBD input power is 50 W and SF_(6)(1.5%SF_(6)/98.5%Ar)flow rate is 100 ml·min-1,the highest DRE can reach 97.7%and the energy yield can reach 11.5 g·(kW·h)-1.Adjusting the catalyst dosage according to the flux of SF_(6)(e.g.,using 10 g catalyst to degrade SF_(6)with a concentration of 1.5%and a flow rate of 80 ml·min-1),the DRE of nearly 99%can be achieved for a long time,which is crucial for industrial application.The mechanism deduction shows that the rich surface and mesopores of the catalyst are beneficial to the adsorption of SF_(6)and intermediates,while the doping of Ni can significantly increase the content of oxygen vacancies to improve the degradation.Meanwhile,when NiO-CeO_(2)is activated by DBD,the free O·can further promote the degradation.It is this coupling effect that leads to the high efficiency and low energy consumption of SF_(6)degradation under mild conditions.It can be expected that this coupling technology route will have a good application prospect in the field of SF_(6)treatment.
