Article pubs.acs.org/IECR
Adsorption of CO2 by Petroleum Coke Nitrogen-Doped Porous Carbons Synthesized by Combining Ammoxidation with KOH Activation Mingli Yang,† Liping Guo,† Gengshen Hu,‡ Xin Hu,*,† Jie Chen,† Siwei Shen,† Wei Dai,† and Maohong Fan*,§ †
College of Chemistry and Life Sciences and ‡Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, People’s Republic of China § Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States S Supporting Information *
ABSTRACT: The goal of our research is developing an efficient and cost-effective carbonaceous CO2 sorbent. Using petroleum coke as the precursor, porous nitrogen-doped carbons were prepared by combining ammoxidation with KOH activation. The assynthesized samples possess highly developed microporosities and large nitrogen loadings. High CO2 adsorption capacities of 3.76−4.57 mmol/g at 25 °C and 5.80−6.62 mmol/g at 0 °C under atmospheric pressure were achieved. Specifically, the sample prepared under mild temperature (650 °C) and low KOH/precursor ratio (KOH/precursor = 2) shows a CO2 uptake of 4.57 mmol/g at 25 °C, among the highest achieved for nitrogen-doped porous carbons. This high CO2 capture capacity can be attributed to the synergistic effect of nitrogen doping and high narrow microporosity of the sorbent. However, experimental evidence suggests that nitrogen doping contributes less than narrow microporosity. Additionally, the CO2/N2 selectivity and CO2 heats of adsorption of the sorbent are as high as 22 and 37 kJ/mol, respectively. The sorbent also shows high cyclic stability, fast kinetics, and superior dynamic CO2 capture capacity under simulated flue gas conditions, thereby demonstrating that it is an excellent candidate for CO2 capture. example, Sayari et al.19 have reported that N-doped carbons show remarkable stability in both structural and chemical aspects under different severe treatment environments, e.g. long-standing exposure to dry CO2, SO2, air, and steam at high temperatures of 130 °C. Thus, carbonaceous materials are considered to be some of the most promising adsorbents for CO2 capture. There are numerous studies in the literature regarding the use of various kinds of carbonaceous sorbents for CO2 capture under ambient conditions (1 bar and 25 °C).20−23 It has been found that narrow micropore size (
