Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effec...Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effective strategy for improving their catalytic activity and durability. In this work, well-defined Rh nanodendrites with very thin triangular branches as subunits are synthesized using a facile diethylene glycol reduction method, assisted by polyethyleneimine as a complex-forming agent and surfactant. For the first time, the methanol oxidation reaction （MOR） on Rh nanocrystals with a well-defined morphology is investigated using various electrochemical techniques in an alkaline medium. Unexpectedly, the as-prepared Rh nanodendrites, with ultrathin nanosheet subunits, exhibit superior electrocatalytic activity and durability during the MOR in an alkaline medium, indicating that Rh nanocrystals with specific morphology may be highly promising alternatives to Pt electrocatalysts in the MOR in an alkaline medium.展开更多
The chiral epoxidation of styrene and its derivatives is an important transformation that has attracted considerable scientific interest in the chemical industry.Herein,we integrate enzymatic catalysis and electrocata...The chiral epoxidation of styrene and its derivatives is an important transformation that has attracted considerable scientific interest in the chemical industry.Herein,we integrate enzymatic catalysis and electrocatalysis to propose a new route for the chiral epoxidation of styrene and its derivatives.Chloroperoxidase(CPO)functionalized with 1-ethyl-3-methylimidazolium bromide(ILEMB)was loaded onto cobalt nitrogen-doped carbon nanotubes(CoN@CNT)to form a biohybrid(CPO-ILEMB/CoN@CNT).H_(2)O_(2)species were generated in situ through a two-electron oxygen reduction reaction(2e–ORR)at CoN@CNT to initiate the following enzymatic epoxidation of styrene by CPO.CoN@CNT had high electroactivity for the ORR to produce H_(2)O_(2)at a more positive potential,prohibiting the conversion of FeⅢ to FeⅡ in the heme of CPO to maintain enzymatic activity.Meanwhile,CoN@CNT could serve as an ideal carrier for the immobilization of CPO-ILEMB.Hence,the coimmobilization of CPO-ILEMB and CoN@CNT could facilitate the diffusion of intermediate H_(2)O_(2),which achieved 17 times higher efficiency than the equivalent amounts of free CPO-ILEMB in bulk solution for styrene epoxidation.Notably,an enhancement(~45%)of chiral selectivity for the epoxidation of styrene was achieved.展开更多
Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from c...Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from carbon dioxide(CO_(2)) are particularly challenging in the petrochemical industry.As a class of porous physical adsorbent,metal-organic frameworks (MOFs) have exhibited great success in separation and purification of light hydrocarbon gas.Herein,we rationally designed four novel MOFs by the strategy of pore space partition(PSP) via introducing triangular tri(pyridin-4-yl)-amine (TPA) into the 1D hexagonal channels of acs-type parent skeleton.By modulating the functional groups of linear dicarboxylate linkers for the parent skeleton,a series of isoreticular PSP-MOFs (SNNU-278-281) were successfully obtained.The synergistic effects of suitable pore size and Lewis basic functional groups make these MOFs ideal C_(2)H_(2)adsorbents.The gas adsorption experimental results show that all MOFs have excellent C_(2)H_(2)uptakes.Specially,SNNU-278demonstrates a high C_(2)H_(2)uptake of 149.7 cm3/g at 273 K and 1 atm.Meanwhile,SNNU-278-281 MOFs also show extremely great C_(2)H_(2)separation from CO_(2)and C_(2)H_(4).The optimized SNNU-281 with highdensity hydroxy groups exhibits extraordinary C_(2)H_(2)/CO_(2)and C_(2)H_(2)/C_(2)H_(4)dynamic breakthrough interval times up to 31 min/g and 17 min/g under 298 K and 1 bar.展开更多
基金This work was supported by National Natural Science Foundation of China （No. 21473111）, Natural Science Foundation of Shaanxi Province （No. 2015JM2043）,and Fundamental Research Funds for the Central Universities （Nos. GK201602002 and GK201503037）.
文摘Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effective strategy for improving their catalytic activity and durability. In this work, well-defined Rh nanodendrites with very thin triangular branches as subunits are synthesized using a facile diethylene glycol reduction method, assisted by polyethyleneimine as a complex-forming agent and surfactant. For the first time, the methanol oxidation reaction （MOR） on Rh nanocrystals with a well-defined morphology is investigated using various electrochemical techniques in an alkaline medium. Unexpectedly, the as-prepared Rh nanodendrites, with ultrathin nanosheet subunits, exhibit superior electrocatalytic activity and durability during the MOR in an alkaline medium, indicating that Rh nanocrystals with specific morphology may be highly promising alternatives to Pt electrocatalysts in the MOR in an alkaline medium.
基金supported by the National Natural Science Foundation of China(22273056)the Science and Technology Innovation Team of Shaanxi Province(2023-CX-TD-27)the Fundamental Research Funds for the Central Universities(GK202202001).
文摘The chiral epoxidation of styrene and its derivatives is an important transformation that has attracted considerable scientific interest in the chemical industry.Herein,we integrate enzymatic catalysis and electrocatalysis to propose a new route for the chiral epoxidation of styrene and its derivatives.Chloroperoxidase(CPO)functionalized with 1-ethyl-3-methylimidazolium bromide(ILEMB)was loaded onto cobalt nitrogen-doped carbon nanotubes(CoN@CNT)to form a biohybrid(CPO-ILEMB/CoN@CNT).H_(2)O_(2)species were generated in situ through a two-electron oxygen reduction reaction(2e–ORR)at CoN@CNT to initiate the following enzymatic epoxidation of styrene by CPO.CoN@CNT had high electroactivity for the ORR to produce H_(2)O_(2)at a more positive potential,prohibiting the conversion of FeⅢ to FeⅡ in the heme of CPO to maintain enzymatic activity.Meanwhile,CoN@CNT could serve as an ideal carrier for the immobilization of CPO-ILEMB.Hence,the coimmobilization of CPO-ILEMB and CoN@CNT could facilitate the diffusion of intermediate H_(2)O_(2),which achieved 17 times higher efficiency than the equivalent amounts of free CPO-ILEMB in bulk solution for styrene epoxidation.Notably,an enhancement(~45%)of chiral selectivity for the epoxidation of styrene was achieved.
基金financially supported by the National Natural Science Foundation of China (No. 22071140)the Natural Science Foundation of Shaanxi Province (No. 2021JLM-20)the Fundamental Research Funds for the Central Universities (No. GK202101002)。
文摘Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from carbon dioxide(CO_(2)) are particularly challenging in the petrochemical industry.As a class of porous physical adsorbent,metal-organic frameworks (MOFs) have exhibited great success in separation and purification of light hydrocarbon gas.Herein,we rationally designed four novel MOFs by the strategy of pore space partition(PSP) via introducing triangular tri(pyridin-4-yl)-amine (TPA) into the 1D hexagonal channels of acs-type parent skeleton.By modulating the functional groups of linear dicarboxylate linkers for the parent skeleton,a series of isoreticular PSP-MOFs (SNNU-278-281) were successfully obtained.The synergistic effects of suitable pore size and Lewis basic functional groups make these MOFs ideal C_(2)H_(2)adsorbents.The gas adsorption experimental results show that all MOFs have excellent C_(2)H_(2)uptakes.Specially,SNNU-278demonstrates a high C_(2)H_(2)uptake of 149.7 cm3/g at 273 K and 1 atm.Meanwhile,SNNU-278-281 MOFs also show extremely great C_(2)H_(2)separation from CO_(2)and C_(2)H_(4).The optimized SNNU-281 with highdensity hydroxy groups exhibits extraordinary C_(2)H_(2)/CO_(2)and C_(2)H_(2)/C_(2)H_(4)dynamic breakthrough interval times up to 31 min/g and 17 min/g under 298 K and 1 bar.
