Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)...Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.展开更多
Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This...Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.展开更多
A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The p...A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.展开更多
Water-soluble N,N-dimethyl[60]fulleropyrro-lidinium iodide (C60(C4H10N+)I-), when dissolved in binarymixtures of tetrahydrofuran and water, was found to exhibit remarkable solvatochromism. Correspondingly, the UV-vis ...Water-soluble N,N-dimethyl[60]fulleropyrro-lidinium iodide (C60(C4H10N+)I-), when dissolved in binarymixtures of tetrahydrofuran and water, was found to exhibit remarkable solvatochromism. Correspondingly, the UV-vis spectra showed obvious changes by variation of the solventcomposition of tetrahydrofuran and water. It was found that both concentration and temperature had strong influence on the stability of monomer-state C60(C4H10N+)I-, while theyhad little effect on the stability of aggregated C60(C4H10N+) I-The formation of cluster was confirmed by TEM and AFMmeasurements.展开更多
文摘Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.
基金National Natural Science Foundation of China,Grant/Award Numbers:52272295,52071137,51977071,51802040,21802020Science and Technology Innovation Program of Hunan Province,Grant/Award Numbers:2021RC3066,2021RC3067+1 种基金Natural Science Foundation of Hunan Province,Grant/Award Number:2020JJ3004Fundamental Research Funds for the Central Universities。
文摘Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.
基金This project supported by the National Key Research and Development Program of China(2016YFC0204300)the National Natural Science Foundation of China(21171055,21333003,21571061)+1 种基金the"Shu Guang"Project of the Shanghai Municipal Education Commission(12SG29)the Commission of Science and Technology of Shanghai Municipality(15DZ1205305)
文摘A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.
文摘Water-soluble N,N-dimethyl[60]fulleropyrro-lidinium iodide (C60(C4H10N+)I-), when dissolved in binarymixtures of tetrahydrofuran and water, was found to exhibit remarkable solvatochromism. Correspondingly, the UV-vis spectra showed obvious changes by variation of the solventcomposition of tetrahydrofuran and water. It was found that both concentration and temperature had strong influence on the stability of monomer-state C60(C4H10N+)I-, while theyhad little effect on the stability of aggregated C60(C4H10N+) I-The formation of cluster was confirmed by TEM and AFMmeasurements.
