A unique redox-coupled biomimetic system was developed, in which Fe-Anderson type polyoxometalates(POMs) were employed as electron transfer mediators(ETMs) and benzenesulfonic acid(BSA)-based deep eutectic solvents(DE...A unique redox-coupled biomimetic system was developed, in which Fe-Anderson type polyoxometalates(POMs) were employed as electron transfer mediators(ETMs) and benzenesulfonic acid(BSA)-based deep eutectic solvents(DESs) were used as electron-donors for aerobic oxidative desulfurization(AODS) of diesel fuel. Different compositions of DESs were used and the polyethylene glycol 2000(PEG2000)/2.5 BSA system showed the highest desulfurization activity, with the removal of dibenzothiophene(DBT) at 60 ℃ reaching 95% in 60 min. The excellent desulfurization activity of the system is due to the in situ formation of peroxysulfonate via a biomimetic process. By constructing a coupled redox system, Fe-Anderson type POMs as ETMs reduce the activation energy of oxygen-activated sulfonate. The physical characteristics of four different DESs were tested. The results show that the conductivity of DESs is correlated with the composition of BSA-based DESs. However, there is no similar trend in viscosity testing at the same temperature, and the maximum viscosity value is obtained for the PEG2000/2.5 BSA system at 60 ℃, which may be associated with the stronger hydrogen bonds. It is worth noting that the PEG2000/2.5 BSA system also possesses the best desulfurization activity, which suggests that the activity of the desulfurization system is related to the strength of the hydrogen bond in DESs. Finally, the biomimetic desulfurization system exhibits excellent performance and good stability under mild reaction conditions(60 ℃, atmospheric pressure, oxygen as the oxidant).展开更多
We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-...We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-assembled mesoporous nanosheets and appeared as soft and hydrophilic foam.Ultrafine Pd NPs(∼6 nm)with high-loading(9.6 wt%)were in situ grown on these mesoporous nanosheets,and their dense spatial distributions were likely to generate nano-confinement catalytic effects on the reactants.Consequently,the CNF-confined Pd NPs(CNF-Pd)exhibited an enhanced room-temperature catalytic activity on the model reaction of 4-nitrophenol hydrogenation with a highest rate constant of 8.8×10^−3 s^−1 and turnover frequency of 2640 h The CNF Pd catalyst possessed good chemical stability and recyclability in aqueous media which could be reused for at least six cycles without losing activity.Moreover,chemoselective reduction of 3 nitrostyrene was achieved with high yield(80%–98%)of 3-aminostyrene in alcohol/water cosolvent.Overall,this work demonstrates a positive nanoconfinement effect of CNFs for developing stable and recyclable metal NP catalysts.展开更多
文摘A unique redox-coupled biomimetic system was developed, in which Fe-Anderson type polyoxometalates(POMs) were employed as electron transfer mediators(ETMs) and benzenesulfonic acid(BSA)-based deep eutectic solvents(DESs) were used as electron-donors for aerobic oxidative desulfurization(AODS) of diesel fuel. Different compositions of DESs were used and the polyethylene glycol 2000(PEG2000)/2.5 BSA system showed the highest desulfurization activity, with the removal of dibenzothiophene(DBT) at 60 ℃ reaching 95% in 60 min. The excellent desulfurization activity of the system is due to the in situ formation of peroxysulfonate via a biomimetic process. By constructing a coupled redox system, Fe-Anderson type POMs as ETMs reduce the activation energy of oxygen-activated sulfonate. The physical characteristics of four different DESs were tested. The results show that the conductivity of DESs is correlated with the composition of BSA-based DESs. However, there is no similar trend in viscosity testing at the same temperature, and the maximum viscosity value is obtained for the PEG2000/2.5 BSA system at 60 ℃, which may be associated with the stronger hydrogen bonds. It is worth noting that the PEG2000/2.5 BSA system also possesses the best desulfurization activity, which suggests that the activity of the desulfurization system is related to the strength of the hydrogen bond in DESs. Finally, the biomimetic desulfurization system exhibits excellent performance and good stability under mild reaction conditions(60 ℃, atmospheric pressure, oxygen as the oxidant).
基金the National Natural Science Foundation of China(31925028 and 31670583)the Special Project for Double First-Class-Cultivation of Innovative Talents(000/41113102)。
文摘We describe the synthesis of even-dispersed palladium nanoparticles(Pd NPs)confined within a cellulose nanofiber(CNF)matrix for developing a high-performance and recyclable catalyst.The CNF matrix was composed of CNF-assembled mesoporous nanosheets and appeared as soft and hydrophilic foam.Ultrafine Pd NPs(∼6 nm)with high-loading(9.6 wt%)were in situ grown on these mesoporous nanosheets,and their dense spatial distributions were likely to generate nano-confinement catalytic effects on the reactants.Consequently,the CNF-confined Pd NPs(CNF-Pd)exhibited an enhanced room-temperature catalytic activity on the model reaction of 4-nitrophenol hydrogenation with a highest rate constant of 8.8×10^−3 s^−1 and turnover frequency of 2640 h The CNF Pd catalyst possessed good chemical stability and recyclability in aqueous media which could be reused for at least six cycles without losing activity.Moreover,chemoselective reduction of 3 nitrostyrene was achieved with high yield(80%–98%)of 3-aminostyrene in alcohol/water cosolvent.Overall,this work demonstrates a positive nanoconfinement effect of CNFs for developing stable and recyclable metal NP catalysts.
