This short review paper aims at assembling the present state of the art of the multiuses of metal oxides in heterogeneous catalysis, concerning liquid and gaseous phases of the reactant mixtures on solid catalysts. It...This short review paper aims at assembling the present state of the art of the multiuses of metal oxides in heterogeneous catalysis, concerning liquid and gaseous phases of the reactant mixtures on solid catalysts. It includes the description of the main types of metal oxide catalysts, of their various preparation procedures and of the main reactions catalysed by them (acid-base type, selective and total oxidations, bi-functional catalysis, photocatalysis, biomass treatments, environmental catalysis and some of the numerous industrial applications). Challenges and prospectives are also discussed.展开更多
Direct synthesis of glycerol carbonate(GC)from CO_(2)and glycerol(a byproduct of biodiesel production)is a route to obtain a high-value chemical from waste and low-cost byproducts but has not yet industrialized due to...Direct synthesis of glycerol carbonate(GC)from CO_(2)and glycerol(a byproduct of biodiesel production)is a route to obtain a high-value chemical from waste and low-cost byproducts but has not yet industrialized due to the lack of efficient catalysts.Ceria(CeO_(2))exhibits the highest catalytic activity and GC selectivity among the heterogeneous catalysts studied so far.However,the mechanism of this reaction over CeO_(2)catalysts has not been studied in detail.Herein,we synthesized CeO_(2)nanocrystals with different morphologies as model catalysts that can predominantly expose(111),(110),and(100)facets,and their surface acid-base properties were characterized using high-sensitivity temperature-programmed desorption of NH3 and CO_(2)with quadrupole mass spectrometry as detector(NH3-TPD-QMS and CO_(2)-TPD-QMS).We found that the catalytic performance(GC formation rate)is strictly linearly dependent on the density of basic sites,which is relevant to the adsorption and activation of CO_(2).In addition,to illustrate a more microscopic reaction mechanisms underlying the formation of GC from CO_(2)and glycerol on all three low-index surfaces(111),(110)and(100),we also performed comprehensive first principles calculations.A three-step Langmuir-Hinshelwood(LH)mechanism was identified in which the annulation reaction is the rate-limiting step.The CeO_(2)(11)surface exhibits the lowest overall activation energy,which agrees well with the catalytic performance that the CeO_(2)nano-octahedra,predominantly exposing(111)facets,have the highest GC formation rate.This work is the first to combine experiments on shaped CeO_(2)model catalysts with first-principles calculations to gain insight into the mechanism of direct synthesis of GC from CO_(2)and glycerol,and will aid in the development of catalysts with improved performance.展开更多
Rechargeable magnesium batteries(RMBs)are considered the promising candidates for post lithium-ion batteries due to the abundant storage,high capacity,and dendrite-rare characteristic of Mg anode.However,the lack of p...Rechargeable magnesium batteries(RMBs)are considered the promising candidates for post lithium-ion batteries due to the abundant storage,high capacity,and dendrite-rare characteristic of Mg anode.However,the lack of practical electrolytes impedes the development and application of RMBs.Here,through a one-step reaction of LiCl congenital-containing Knochel–Hauser base TMPL(2,2,6,6-tetrame thylpiperidinylmagnesium chloride lithium chloride complex)with Lewis acid AlCl_(3),we successfully synthesized an efficient amino-magnesium halide TMPLA electrolyte.Raman and mass spectroscopy identified that the electrolyte comprises the typical di-nuclear copolymer[Mg_(2)Cl_(3)·6THF]+cation group and[(TMP)2AlCl_(2)]-anion group,further supported by the results of density functional theory calculations(DFT)and the Molecular dynamics(MD)simulations.The TMPLA electrolyte exhibits promising electrochemical performance,including available anodic stability(>2.65 V vs.SS),high ionic conductivity(6.05mS cm^(-1)),and low overpotential(<0.1 V)as well as appropriate Coulombic efficiency(97.3%)for Mg plating/stripping.Both the insertion Mo6S8cathode and conversion Cu S cathode delivered a desirable electrochemical performance with high capacity and good cycling stability based on the TMPLA electrolyte.In particular,when compatible with low cost and easily synthesized Cu S,the Cu S||Mg cell displayed an extremely high discharge capacity of 458.8 mAh g^(-1)for the first cycle and stabilized at 170.2 mAh g^(-1)with high Coulombic efficiency(99.1%)after 50 cycles at 0.05 C.Our work proposes an efficient electrolyte with impressive compatibility with Mg anode and insertion/conversion cathode for practical RMBs and provides a more profound knowledge of the Lewis acid–base reaction mechanisms.展开更多
文摘This short review paper aims at assembling the present state of the art of the multiuses of metal oxides in heterogeneous catalysis, concerning liquid and gaseous phases of the reactant mixtures on solid catalysts. It includes the description of the main types of metal oxide catalysts, of their various preparation procedures and of the main reactions catalysed by them (acid-base type, selective and total oxidations, bi-functional catalysis, photocatalysis, biomass treatments, environmental catalysis and some of the numerous industrial applications). Challenges and prospectives are also discussed.
基金supported by the National Natural Science Foundation of China(No.21902005)Beihang Universityand State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology).
文摘Direct synthesis of glycerol carbonate(GC)from CO_(2)and glycerol(a byproduct of biodiesel production)is a route to obtain a high-value chemical from waste and low-cost byproducts but has not yet industrialized due to the lack of efficient catalysts.Ceria(CeO_(2))exhibits the highest catalytic activity and GC selectivity among the heterogeneous catalysts studied so far.However,the mechanism of this reaction over CeO_(2)catalysts has not been studied in detail.Herein,we synthesized CeO_(2)nanocrystals with different morphologies as model catalysts that can predominantly expose(111),(110),and(100)facets,and their surface acid-base properties were characterized using high-sensitivity temperature-programmed desorption of NH3 and CO_(2)with quadrupole mass spectrometry as detector(NH3-TPD-QMS and CO_(2)-TPD-QMS).We found that the catalytic performance(GC formation rate)is strictly linearly dependent on the density of basic sites,which is relevant to the adsorption and activation of CO_(2).In addition,to illustrate a more microscopic reaction mechanisms underlying the formation of GC from CO_(2)and glycerol on all three low-index surfaces(111),(110)and(100),we also performed comprehensive first principles calculations.A three-step Langmuir-Hinshelwood(LH)mechanism was identified in which the annulation reaction is the rate-limiting step.The CeO_(2)(11)surface exhibits the lowest overall activation energy,which agrees well with the catalytic performance that the CeO_(2)nano-octahedra,predominantly exposing(111)facets,have the highest GC formation rate.This work is the first to combine experiments on shaped CeO_(2)model catalysts with first-principles calculations to gain insight into the mechanism of direct synthesis of GC from CO_(2)and glycerol,and will aid in the development of catalysts with improved performance.
基金financial support from the National Natural Science Foundation of China(Nos.21975159,2157316)the Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2018-117)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.WH410260401/006)。
文摘Rechargeable magnesium batteries(RMBs)are considered the promising candidates for post lithium-ion batteries due to the abundant storage,high capacity,and dendrite-rare characteristic of Mg anode.However,the lack of practical electrolytes impedes the development and application of RMBs.Here,through a one-step reaction of LiCl congenital-containing Knochel–Hauser base TMPL(2,2,6,6-tetrame thylpiperidinylmagnesium chloride lithium chloride complex)with Lewis acid AlCl_(3),we successfully synthesized an efficient amino-magnesium halide TMPLA electrolyte.Raman and mass spectroscopy identified that the electrolyte comprises the typical di-nuclear copolymer[Mg_(2)Cl_(3)·6THF]+cation group and[(TMP)2AlCl_(2)]-anion group,further supported by the results of density functional theory calculations(DFT)and the Molecular dynamics(MD)simulations.The TMPLA electrolyte exhibits promising electrochemical performance,including available anodic stability(>2.65 V vs.SS),high ionic conductivity(6.05mS cm^(-1)),and low overpotential(<0.1 V)as well as appropriate Coulombic efficiency(97.3%)for Mg plating/stripping.Both the insertion Mo6S8cathode and conversion Cu S cathode delivered a desirable electrochemical performance with high capacity and good cycling stability based on the TMPLA electrolyte.In particular,when compatible with low cost and easily synthesized Cu S,the Cu S||Mg cell displayed an extremely high discharge capacity of 458.8 mAh g^(-1)for the first cycle and stabilized at 170.2 mAh g^(-1)with high Coulombic efficiency(99.1%)after 50 cycles at 0.05 C.Our work proposes an efficient electrolyte with impressive compatibility with Mg anode and insertion/conversion cathode for practical RMBs and provides a more profound knowledge of the Lewis acid–base reaction mechanisms.
