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Issue 44, 2017
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Probing the role of O-containing groups in CO2 adsorption of N-doped porous activated carbon

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Abstract

Porous activated carbons (PACs) are promising candidates to capture CO2 through physical adsorption because of their chemical stability, easy-synthesis, cost-effectiveness and good recyclability. However, their low CO2 adsorption capacity, especially low CO2/N2 selectivity, has limited their practical applications. In this work, an optimized PAC with a large specific surface area, a small micropore size, and a large micropore volume has been synthesized by one-step carbonization/activation of casein using K2CO3 as a mild activation agent. It showed a remarkably enhanced CO2 adsorption capacity as high as 5.78 mmol g−1 and an excellent CO2/N2 selectivity of 144 (25 °C, 1 bar). Based on DFT calculations and experimental results, the coexistence of adjacent pyridinic N and –OH/–NH2 species was proposed for the first time to make an important contribution to the ultra-high CO2 adsorption performance, especially CO2/N2 selectivity. This work provides effective guidance to design PAC adsorbents with high CO2 adsorption performance. The content of pyridine N combined with –OH/–NH2 was further elevated by additional nitrogen introduction, resulting in a further enhanced CO2 adsorption capacity up to 5.96 mmol g−1 (25 °C, 1 bar). All these results suggest that, in addition to the well-defined pore structure, pyridinic N with neighboring OH or NH2 species played an important role in enhancing the CO2 adsorption performance of PACs, thus providing effective guidance for the rational design of CO2 adsorbents.

Graphical abstract: Probing the role of O-containing groups in CO2 adsorption of N-doped porous activated carbon

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Publication details

The article was received on 12 Aug 2017, accepted on 11 Oct 2017 and first published on 11 Oct 2017


Article type: Paper
DOI: 10.1039/C7NR05977A
Citation: Nanoscale, 2017,9, 17593-17600
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    Probing the role of O-containing groups in CO2 adsorption of N-doped porous activated carbon

    M. Wang, X. Fan, L. Zhang, J. Liu, B. Wang, R. Cheng, M. Li, J. Tian and J. Shi, Nanoscale, 2017, 9, 17593
    DOI: 10.1039/C7NR05977A

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