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2019 Volume 35 Issue 5
2019, 35(5): 753-768
doi: 10.11862/CJIC.2019.099
Abstract:
Selective catalytic reduction of NOx with NH3 is a powerful technique for the abatement of NOx. The operating temperature window of commercial V2O5-WO3(MoO3)/TiO2 denitration catalysts is too high to satisfy the requirements of low temperature and wide operating temperature window, and therefore the development of low-temperature denitration catalysts with wide operating temperature window becomes a hot spot of this research field in recent years. Iron-based catalysts are widely used in the low-temperature NH3-selective catalytic reduction (NH3-SCR) of NOx because of their good redox ability, rich resource reserves, low-cost, non-toxic and harmlessness, etc.. Based on the different roles of Fe2O3 in NH3-SCR catalysts, we have performed a systematic review of the latest research progress of iron-based catalysts in the NH3-SCR reaction for the following aspects:Fe2O3 used as support, promoter, active species, and iron-based catalysts with new structures. In addition, the NH3-SCR reaction mechanism and H2O/SO2 tolerance over iron-based catalysts are emphasized. Finally, the perspectives on the opportunities and challenges of iron-based catalysts for NH3-SCR in future research are presented.
Selective catalytic reduction of NOx with NH3 is a powerful technique for the abatement of NOx. The operating temperature window of commercial V2O5-WO3(MoO3)/TiO2 denitration catalysts is too high to satisfy the requirements of low temperature and wide operating temperature window, and therefore the development of low-temperature denitration catalysts with wide operating temperature window becomes a hot spot of this research field in recent years. Iron-based catalysts are widely used in the low-temperature NH3-selective catalytic reduction (NH3-SCR) of NOx because of their good redox ability, rich resource reserves, low-cost, non-toxic and harmlessness, etc.. Based on the different roles of Fe2O3 in NH3-SCR catalysts, we have performed a systematic review of the latest research progress of iron-based catalysts in the NH3-SCR reaction for the following aspects:Fe2O3 used as support, promoter, active species, and iron-based catalysts with new structures. In addition, the NH3-SCR reaction mechanism and H2O/SO2 tolerance over iron-based catalysts are emphasized. Finally, the perspectives on the opportunities and challenges of iron-based catalysts for NH3-SCR in future research are presented.
2019, 35(5): 769-779
doi: 10.11862/CJIC.2019.063
Abstract:
α-MnO2 nanotubes were developed as host material to fill with sulfur in their tubular hollow space, and then the sulfur were further encapsulated by a thin layer of poly(3, 4-ethylenedioxythiophene) (PEDOT) exterior coating via an in situ polymerization process. Such a dual-confined sulfur cathode, denoted as S@α-MnO2-PEDOT, showed high performance in lithium-sulfur batteries. It could reach a capacity of 774.4 mAh·g-1 at a current density of 1 675 mA·g-1 (1C) after 200 cycles and 854.1 mAh·g-1 at a current density of 3 350 mA·g-1 (2C), manifesting excellent cycling stability and rate capability. The outstanding performances are attributed to the new architecture. In the novel architecture, α-MnO2 nanotubes not only provide the physical confinement for sulfur, but also enhance the chemical interaction between the sulfur host material and polysulfides. Simultaneously, PEDOT was introduced to enhance conductivity of sulfur-containing nanocomposites and further reduce the loss of sulfur due to volumetric change and the excessive dissolution of lithium polysulfides.
α-MnO2 nanotubes were developed as host material to fill with sulfur in their tubular hollow space, and then the sulfur were further encapsulated by a thin layer of poly(3, 4-ethylenedioxythiophene) (PEDOT) exterior coating via an in situ polymerization process. Such a dual-confined sulfur cathode, denoted as S@α-MnO2-PEDOT, showed high performance in lithium-sulfur batteries. It could reach a capacity of 774.4 mAh·g-1 at a current density of 1 675 mA·g-1 (1C) after 200 cycles and 854.1 mAh·g-1 at a current density of 3 350 mA·g-1 (2C), manifesting excellent cycling stability and rate capability. The outstanding performances are attributed to the new architecture. In the novel architecture, α-MnO2 nanotubes not only provide the physical confinement for sulfur, but also enhance the chemical interaction between the sulfur host material and polysulfides. Simultaneously, PEDOT was introduced to enhance conductivity of sulfur-containing nanocomposites and further reduce the loss of sulfur due to volumetric change and the excessive dissolution of lithium polysulfides.
