5 research outputs found

    Nitrogen-Doped Porous Carbons Derived from Carbonization of a Nitrogen-Containing Polymer: Efficient Adsorbents for Selective CO<sub>2</sub> Capture

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    Because of their abundant porosity, tunable surface properties, and high stability, N-doped porous carbons (NPCs) are highly promising for CO<sub>2</sub> capture. Carbonization of N-containing polymers is frequently used for the preparation of NPCs, while such an approach is hindered by the high cost of some polymer precursors. In the present study, we report for the first time the fabrication of NPCs through the rational choice of the low-cost, N-rich polymer NUT-2 (NUT indicates Nanjing Tech University) as the precursor, which was obtained from polymerization of easily available monomers under mild conditions in the absence of any catalysts. Through carbonization at different temperatures (500–800 °C), NPCs with various porosity and nitrogen contents are obtained. The pore structure and CO<sub>2</sub>-philic (N-doped) sites are responsible for the adsorption performance, while the highest surface area does not lead to the highest CO<sub>2</sub> adsorption capacity. For the sample carbonized at 600 °C (NPC-2-600), the adsorption capacity on CO<sub>2</sub> is as high as 164.7 cm<sup>3</sup> g<sup>–1</sup> at 0 °C and 1 bar, which is much better than that of the benchmarks, such as activated carbon (62.5 cm<sup>3</sup> g<sup>–1</sup>) and 13X zeolite (91.8 cm<sup>3</sup> g<sup>–1</sup>), as well as most reported carbon-based adsorbents. We also demonstrate that the present NPCs can be regenerated completely under mild conditions. The present adsorbents may provide promising candidates for the capture of CO<sub>2</sub> from various mixtures, such as flue gas and natural gas

    Green Synthesis of Noble Nanometals (Au, Pt, Pd) Using Glycerol under Microwave Irradiation Conditions

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    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. Their shapes can be changed by adding different surfactants. In the presence of CTAB, Au nanosheets were formed within 2 min where the size of Au nanosheets can be controlled by the microwave irradiation time and glycerol content

    Facile Fabrication of Cuprous Oxide-based Adsorbents for Deep Desulfurization

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    Deep desulfurization via π-complexation adsorption is an effective approach for the selective capture of aromatic sulfur compounds. Among various π-complexation adsorbents, Cu­(I)-containing materials attract great attention due to their low cost and high efficiency. In the present study, a one-pot thermal treatment strategy was developed to fabricate Cu<sub>2</sub>O-based adsorbents for the first time. As-synthesized mesoporous silica SBA-15 was directly used as the support and the precursor Cu­(NO<sub>3</sub>)<sub>2</sub> was introduced to the confined space between silica walls and template. The subsequent one-pot thermal treatment plays a triple role by decomposing Cu­(NO<sub>3</sub>)<sub>2</sub> to CuO, removing the template P123, and reducing CuO to Cu<sub>2</sub>O. In contrast to the traditional approach, our strategy provides a more convenient method for the preparation of Cu<sub>2</sub>O-based adsorbents. For a typical material CuAS-3 derived from as-synthesized SBA-15, the yield of Cu­(I) is 73.3%, which is obviously higher than its counterpart CuCS-3 prepared from template-free SBA-15 (53.3%). We also demonstrate that the resultant materials are active in adsorptive desulfurization, and the amount of thiophene captured can reach 0.35 mmol·g<sup>–1</sup> over CuAS-3, which is obviously better than that over CuCS-3 (0.27 mmol·g<sup>–1</sup>). Furthermore, the activity in adsorptive desulfurization can be well recovered with no apparent loss. The convenient preparation, high activity, and good reusability make the present materials highly promising for utilization as adsorbents in deep desulfurization

    Oriented Built-in Electric Field Introduced by Surface Gradient Diffusion Doping for Enhanced Photocatalytic H<sub>2</sub> Evolution in CdS Nanorods

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    Element doping has been extensively attempted to develop visible-light-driven photocatalysts, which introduces impurity levels and enhances light absorption. However, the dopants can also become recombination centers for photogenerated electrons and holes. To address the recombination challenge, we report a gradient phosphorus-doped CdS (CdS-P) homojunction nanostructure, creating an oriented built-in electric-field for efficient extraction of carriers from inside to surface of the photocatalyst. The apparent quantum efficiency (AQY) based on the cocatalyst-free photocatalyst is up to 8.2% at 420 nm while the H<sub>2</sub> evolution rate boosts to 194.3 μmol·h<sup>–1</sup>·mg<sup>–1</sup>, which is 58.3 times higher than that of pristine CdS. This concept of oriented built-in electric field introduced by surface gradient diffusion doping should provide a new approach to design other types of semiconductor photocatalysts for efficient solar-to-chemical conversion

    Oriented Built-in Electric Field Introduced by Surface Gradient Diffusion Doping for Enhanced Photocatalytic H<sub>2</sub> Evolution in CdS Nanorods

    No full text
    Element doping has been extensively attempted to develop visible-light-driven photocatalysts, which introduces impurity levels and enhances light absorption. However, the dopants can also become recombination centers for photogenerated electrons and holes. To address the recombination challenge, we report a gradient phosphorus-doped CdS (CdS-P) homojunction nanostructure, creating an oriented built-in electric-field for efficient extraction of carriers from inside to surface of the photocatalyst. The apparent quantum efficiency (AQY) based on the cocatalyst-free photocatalyst is up to 8.2% at 420 nm while the H<sub>2</sub> evolution rate boosts to 194.3 μmol·h<sup>–1</sup>·mg<sup>–1</sup>, which is 58.3 times higher than that of pristine CdS. This concept of oriented built-in electric field introduced by surface gradient diffusion doping should provide a new approach to design other types of semiconductor photocatalysts for efficient solar-to-chemical conversion
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