Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A. This journal is The Royal Society of Chemistry 2018 Supporting Information (Journal of Materials Chemistry A) for Development of highly effective CaO@Al 2 O 3 hierarchitectured CO 2 sorbents via a scalable limited space chemical vapor deposition technique Rui Han, Jihui Gao*, Siyu Wei, Yanlin Su, Yukun Qin School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China, Tel: (86)-0451-8641 3231; Fax: (86)-0451-8641 2528; E-mail address: gaojh@hit.edu.cn Texts S1-S3 Figures S1-S8 Table S1
Text S1 The decomposition of Ca precursor was analyzed in a thermogravimetric analyzer. About 10 mg sample was placed in the pan and then was heated to 950 C under a rate of 5 C/min. The whole processes were conducted under nitrogen atmosphere. It is known that only one weight loss peak occurs for CaCO 3 (Figure S1a). In comparison, the thermograms (Figure S1b-f) indicate many weight loss peaks during the decompositions of Ca precursor. These weight losses include following stages: (i) dehydration; (ii) decomposition of the organic calcium to calcium carbonate; and (iii) decomposition of calcium carbonate to calcium oxide. 1
Figure S1. TG curves of Ca precursor. 2
Text S2 To obtain pure porous carbon, a certain amount of aqueous HCl solution was added to remove the unwanted substances, and further washed with deionized water until ph = 7. Subsequently, the wet sample was evaporated at 100 for 12 h. The XRD pattern of the resulting carbon is shown in Fig. S3a. This sample exhibited the characteristic C (002) peaks at approximately 25, which suggests largely amorphous structures. The specific surface area and pore structure of the carbon sample were further determined based on the N 2 adsorption desorption isotherms. The BET surface area of the carbon from the calcium citric was as high as 495.9 m 2 /g. As shown in Fig. S3b, the pore size distribution was mainly centered between 2 and 4 nm, which indicates a mesoporous carbon. In addition, the isotherm exhibited characteristics of type IV with a pronounced hysteresis loop according to the IUPAC classification, which contains a sharp capillary condensation step at relative high pressures of P/P0 > 0.4, indicating its high mesoporosity (Fig. S3c). Moreover, the weight loss analysis of porous carbon in air atmosphere was measured and shown in Fig. S3d. The weightlessness slope is very steep, which indicated a uniform chemical structure. 3
Figure S2. Characterizations of porous carbon. (a) XRD; (b) pore size distribution; (c) adsorption desorption isotherm; and (d) TG weight loss curves under air atmosphere. 4
Figure S3. XRD patterns of CCi-A and CCi-N. 5
Figure S4. Barrett Joyner Halenda pore size distribution of CCi-A and CCi-N. 6
Figure S5. TG and DTA curves of aluminium acetylacetonate (Al(acac) 3 ). 7
Figure S6. N 2 -sorption isotherms of CCi-A-CA90, CCi-A-CA90 and CCi-CaO. 8
Figure S7. The EDS analysis of the synthetic sorbents. (a) CCi-A-CA90; (b) CCi-N-CA90. 9
Text S3 The CO 2 uptake quantity per unit sorbent, X N, was given by: X N = m N m cal m cal (1) where X N is the CO 2 uptake capacity in the form of grams of CO 2 /gram of sorbent. The carbonation conversion rate, R, was calculated as: R = dx N dt (2) where R is the carbonation conversion rate, X N is the CO 2 uptake capacity, t is the reaction time. 10
Figure S8. Comparison of the capacity between the sorbents here and in the literature (representative results only) [1] Liu F Q, Li W H, Liu B C, et al. Synthesis, characterization, and high temperature CO 2 capture of new CaO based hollow sphere sorbents[j]. Journal of Materials Chemistry A, 2013, 1(27):8037-8044. [2] Pan X, Xie M, Cheng Z, et al. CO 2 Capture Performance of CaO-Based Sorbents Prepared by a Sol Gel Method[J]. Industrial & Engineering Chemistry Research, 2013, 52(34):12161-12169. [3] Angeli S D, Martavaltzi C S, Lemonidou A A. Development of a novel-synthesized Ca-based CO 2, sorbent for multicycle operation: Parametric study of sorption[j]. Fuel, 2014, 127(7):62-69. [4] Qin C, Liu W, An H, et al. Fabrication of CaO-based sorbents for CO₂ capture by a mixing method[j]. Environmental Science & Technology, 2012, 46(3):1932-9. [5] Radfarnia H R, Iliuta M C. Metal oxide-stabilized calcium oxide CO 2, sorbent for multicycle 11
operation[j]. Chemical Engineering Journal, 2013, 232(9):280-289. [6] Martavaltzi C S, Lemonidou A A. Parametric Study of the CaO Ca 12 Al 14 O 33 Synthesis with Respect to High CO 2 Sorption Capacity and Stability on Multicycle Operation[J]. Industrial & Engineering Chemistry Research, 2008, 47(23):9537-9543. [7] Zhang M, Peng Y, Sun Y, et al. Preparation of CaO Al 2 O 3, sorbent and CO 2, capture performance at high temperature[j]. Fuel, 2013, 111(9):636-642. [8] Stendardo S, Andersen L K, Herce C. Self-activation and effect of regeneration conditions in CO 2 carbonate looping with CaO Ca 12 Al 14 O 33, sorbent[j]. Chemical Engineering Journal, 2013, 220(6):383-394. [9] Koirala R, Reddy G K, Smirniotis P G. Single Nozzle Flame-Made Highly Durable Metal Doped Ca-Based Sorbents for CO 2 Capture at High Temperature[J]. Energy & Fuels, 2012, 26(5):3103-3109. [10]Kierzkowska A M, Poulikakos L V, Broda M, et al. Synthesis of calcium-based, Al 2 O 3 - stabilized sorbents for CO 2 capture using a co-precipitation technique[j]. International Journal of Greenhouse Gas Control, 2013, 15(15):48-54. [11]Zhou Z, Qi Y, Xie M, et al. Synthesis of CaO-based sorbents through incorporation of alumina/aluminate and their CO 2, capture performance[j]. Chemical Engineering Science, 2012, 74(22):172-180. [12]Liu F Q, Li W H, Liu B C, et al. Synthesis, characterization, and high temperature CO 2 capture of new CaO based hollow sphere sorbents[j]. Journal of Materials Chemistry A, 2013, 1(27):8037-8044. [13]Li Z S, Cai N S, Huang Y Y, et al. Synthesis, experimental studies, and analysis of a new 12
calcium-based carbon dioxide absorbent[j]. Energy & Fuels, 2005, 19(4):1447-1452. [14]Florin N H, Blamey J, Fennell P S. Synthetic CaO-Based Sorbent for CO 2 Capture from Large-Point Sources[J]. Energy Fuels, 2010, 24(8):4598-4604. 13
Table S1. The texture features of various sorbents used. Sorbents Surface area (m 2 g -1 ) Pore volume (cm 3 g -1 ) Average pore size (nm) CCi-CaO 14.0 0.047 12.2 ncc-cao 6.3 0.014 7.7 CF-CaO 4.7 0.011 12.0 CA-CaO 13.7 0.058 16.9 CL-CaO 13.0 0.045 11.8 CG-CaO 25.1 0.054 7.6 CCi-A-CA90 12.5 0.027 11.7 ncc-a-ca90 9.0 0.022 12.0 CF-A-CA90 9.8 0.027 11.4 CA-A-CA90 11.6 0.034 11.4 CL-A-CA90 11.0 0.022 7.7 CG-A-CA90 22.0 0.039 7.1 14