Hongyan He

Improving SO2 capture by tuning functional groups on the cation of pyridinium-based ionic liquids

In this work, three kinds of novel functionalized ionic liquids (ILs) [NEt2C2Py][SCN], [C4OPy][SCN] and [C4CNPy][SCN] were developed by introducing a tertiary amino group, ether group and nitrile group on the pyridinium cation to improve SO2 absorption performances. Among the investigated ILs, [NEt2C2Py][SCN] showed the highest absorption capacity of 1.06 gSO2 gIL−1 under ambient conditions due to a combination of chemical and physical absorption. By contrast, the enhancement in SO2 capacity by [C4CNPy][SCN] and [C4OPy][SCN] is mainly ascribed to the stronger physical interaction between ILs and SO2 than the conventional IL [C4Py][SCN]. Meanwhile, higher SO2/CO2 selectivity was also obtained using these functionalized ILs, which was increased up to 41% comparing with that of [C4Py][SCN]. Moreover, the effect of water on SO2 capacity and the absorption mechanism were studied. The results indicated that the presence of water caused a slight decrease in SO2 capacity of [C4CNPy][SCN] and [C4OPy][SCN] because of physical absorption, whereas a slight increase in SO2 capacity by [NEt2C2Py][SCN] due to the formation of hydrogen sulfite salts through chemical absorption. In addition, three kinds of cation-functionalized ILs could remain the stable absorption performance after five cycles of absorption and desorption, implying these ILs show great potentials for SO2 capture.

The Hydrogen-Bonding Interactions between 1-Ethyl-3-Methylimidazolium Lactate Ionic Liquid and Methanol*

1-Ethyl-3-Methylimidazolium lactate ([EMIM][LAC]) is an environmental friendly ionic liquid with potential industrial applications. Attenuated total reflectance infrared spectroscopy (ATR-IR) and density functional theory (DFT) calculations were employed to investigate the molecular interactions between methanol and [EMIM][LAC]. The infrared spectra were analyzed by two methods: excess spectroscopy and two-dimensional (2D) correlation spectroscopy. In the ATR-FTIR spectra, v(C4,5-H), v(C2-H), v(alkyl), v(-OD), and v(-COO) all show blue shifts upon addition of methanol. 2D correlation analysis indicated that the v(imidazolium ring C-H) band varies before that of v(alkyl C-H) with increasing CD3OD content. The following sequential order of interaction strength is established by DFT calculations: EMIM-methanol -LAC > EMIM-LAC > LAC-methanol > EMIM-methanol.

Deep Desulfurization of Gasoline Fuel using FeCl3-Containing Lewis-Acidic Ionic Liquids

The FeCl3-containing Lewis-acidic ionic liquids (ILs) [C6mim]Cl/FeCl3(1:1.5), [C6mim]Cl/FeCl3(1:2), [C8mim]Cl/FeCl3(1:1.5), and [C8mim]Cl/FeCl3(1:2) were used as extractants for desulfurization of model fuel and gasoline fuel, respectively. The results demonstrate that these ILs are effective for the removal of sulfur compounds from model fuel under different mass ratio of IL to model fuel (1:1, 1:3, 1:5, 1:10) at 25°C. The extractive performance of ILs increased as the molar ratio of FeCl3 to [Cnmim]Cl(n = 6, 8) varied from 1:1 to 1:2. The selectivity of sulfur compounds by extraction process followed the order of dibenzothiophene (DBT)>benzothiophene (BT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT). The sulfur removal of gasoline fuel containing sulfur content of 440.3 ppmw could be up to 85.8%; that is to say that the sulfur content of gasoline fuel varied from 440.3 ppmw to 62.4 ppmw after one extraction stage. Moreover, the [C6mim]Cl/FeCl3(1:2) can be recycled for at least 4 times with a little decrease in the desulfurization activity.

Carbon-supported hollow palladium nanoparticles with enhanced electrocatalytic performance

Carbon-supported palladium nanoparticles (NPs) with hollow interiors (hPdNPs/C) are fabricated via a facile approach. In this strategy, core–shell NPs with an Ag core and an Ag–Pd alloy shell (Ag@Ag–Pd) are first synthesized in oleylamine by a galvanic replacement reaction between Ag seed particles and Pd2+ ion precursors. Then the core–shell Ag@Ag–Pd NPs are loaded on the XC-72 carbon supports and refluxed in acetic acid to remove the original organic surfactant. The carbon-supported core–shell Ag@Ag–Pd NPs are subsequently agitated in saturated Na2S or NaCl solution for 24 h to eliminate the Ag component from the core and shell regions, leading to the formation of hPdNPs/C. Specifically, the hPdNPs/C generated by NaCl treatment exhibit superior catalytic activity and durability for formic acid oxidation reaction (FAOR) and oxygen reduction reaction (ORR), compared with the commercial Pd/C catalysts from Johnson Matthey, mainly due to the high electrochemically active surface areas (ECSAs) of the hollow structure, whereas the hPdNPs/C obtained by Na2S treatment display very poor catalytic performance due to the serious poisoning induced by S2− adsorption.