properties via a simple hydrolysis-based approach

Transcription

1 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry 01 Supporting Information Salable synthesis of hollow O nanoubes with unique optial properties via a simple hydrolysis-based approah ui Liu, Yue Zhou, Sergei A. ulinih, Jia-Jun Li, Li-Li an, Shi-Zhang Qiao, Xi-Wen Du * 1. Raw miropowder. Figure S1. (a) SEM and (b) TEM images of raw miro-powder used as initial material.. Charaterizations of hollow O nanoubes. Figure S. (a) RTEM image and SAED pattern (b) of the shell of a hollow O nanoube.

2 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry 01. Calulation of the p threshold value for the omplexation of in aqueous solutions. The dissolution of in aqueous proeeds in aordane with the following reations: Ionization Complexation (1) + x x 1+ x (x=1, ) () Therefore, the total solubility (S) of an be represented as the sum of several soluble -ontaining speies: [1] S = + (aq) = β 1 β β = (1 - β β +β ) () sp where is the equilibrium onstant, + and - are the onentrations of + sp and - ions, respetively. β 1, β, and β are the umulative stabilization onstants of, -, and - - 4, respetively ( , , ). [1] 10 When the p value of the aqueous solution is adjusted by adding, two effets an influene the solubility of. As the added amount of inreases, first the ommon-ion effet takes plae, where the inrease of - ion onentration an lower the solubility of, and the onentration of -ontaining speies reahes a minimum value. Further addition of an ause the other effet, omplexation,

3 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry 01 where an reat with, giving rise to soluble x 1+ x and thus improving the solubility of. Therefore, the lowest onentration of -ontaining speies (or the minimum solubility of ) orresponds to the onentration of - ions at whih the omplexation reation begins to proeed. This value an be determined by: ds d - ( β + β - ) 0 (4) sp whih gives M (min) The ionization onstant of is , whih is muh lower than that of in water. ene, most of - ions originate from the ionization of. As a result, the onentration of + ions is nearly equal to that of - ions. p lg lg Therefore, the omplexation reation takes plae when p is below Calulation of the lower p limit for the alkaline hydrolysis of in aqueous solution. The ionization onstant ( ) of an be alulated based on the ionization reation [equation (1)]: a a (5) where, 7 a for in water. The saturated solubility of in water ( s ) is M, [] and s

4 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry 01 Aording to the above, the onentration of + ions in the saturated aqueous solution is determined as = M. The orresponding p value of the saturated aqueous solution is then alulated as follows. A hydrolysis equilibrium exists in the saturated aqueous solution + + O + O + (6) The dissolution equilibrium onstant sp6 of reation (6) follows: O 6 (7) sp The onstant sp6 for the hydrolysis of is unknown. owever, equation (6) an be departed into two basi equations: O O (8) - O + O (9) Oasionally, both of them have the same dissolution equilibrium onstant (see ref. [] ) presented below: w sp Sine Equation 6 = Equation 8-Equation 9, the dissolution equilibrium onstant of Equation 6 an be obtained as: 14 w sp6 1 (10) The following equation an be obtained by ombing Equation 6 with Equation 10: sp9

5 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry 01 ( ) 0 (11) M The p value of the saturated aqueous solution is then determined as: p lg Charaterization of the produt of the reation of with water at different p values Figure S. TEM images of the produt of the reation between and water at different p values, (a) 4., () 8.5. RTEM images of the produt of the reation of with water at different p values, (b) 4., (d) 8.5.

6 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry 01 Figure S4. SEM image (a) and XRD pattern (b) of the nanoubes obtained after the dissolution of miro-powder in aidi water (p= 0.5) followed by an inrease in p to 6.5 for a few seonds. Figure S5. XRD patterns of the produt after the reation of with water (p 6.5) for different times.

7 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry TEM images of the intermediate produts of the reation of with water at p of 6.5 for different times. Figure S6 TEM images of the intermediate produts obtained through the reation of with water at p of 6.5 for different times. (a) the produt obtained after min reation, (b) high resolution TEM image of a O nanopartile on a nanoube in (a), () the produt obtained after 5 min reation, (d) high magnifiation TEM image of a nanoube in ().

8 Eletroni Supplementary Material (ESI) for Journal of Materials Chemistry A This journal is The Royal Soiety of Chemistry Charaterization of the onjuntion of hollow O nanoubes with RhB Figure S7. FTIR spetra of RhB and a mixture of hollow O nanoubes and RhB. Referenes: [1] D. F. Liu, L.T. uang, and W. Dong, Inorgani Chemials Industry 008, 40, 7-9. [] J. A. Dean, Lange's andbook of Chemistry, 15th.ed