[Supplementary Information]

Effects of SiO2 incorporation sequence on the catalytic properties of iron-based Fischer-Tropsch catalysts containing residual sodium

Dong Hyun Chun, Ji Chan Park, Ho-Tae Lee, Jung-Il Yang, SungJun Hong, Heon Jung * Korea Institute of Energy Research, 152 Gajeong-Ro, Yuseong-Gu, Daejeon 305-343, Republic of Korea

Figure S1. The XRD patterns of the precursor samples: (a) AW-P and (b) AP-P

Figure S1 shows the XRD patterns of precursor samples for AW (denoted as AW-

P) and AP (denoted as AP-P). The XRD results revealed that the precursor samples for

both catalysts mainly consisted of a FeOOH (goethite) phase and a Fe5O7(OH)4H2O

(ferrihydrite, syn) phase.

Figure S2. The XRD patterns of the fresh catalysts (a) without SiO2 incorporation and

(b) with SiO2 incorporation

Figure S2 shows the XRD patterns of the catalysts with and without SiO2 incorporation. The chemical composition of the catalysts without SiO2 analyzed by XRF was 100Fe/5.08Cu/5.20K in part per weight. The XRD patterns of the catalysts without

SiO2 were closely matched to those of a Fe2O3 (hematite, syn) phase, indicating that the goethite and ferrihydrite phases are almost completely decomposed to the hematite phase during the calcination treatment at 400 C. In contrast, the crystal structure of the catalysts with SiO2 (AW) can be identified as a combination of a hematite phase and a

Fe5O7(OH)4H2O (ferrihydrite, syn) phase. This implies that the ferrihydrite phase, a

metastable phase at 400 C, was stabilized by the incorporated SiO2, as several researchers have reported [Herbillon A, Tran Vinh An J (1969) J Soil Sci 20:223; Childs CW, Kanasaki N, Yoshinaga N (1993) Clay Sci 9:65; Glasauer SM, Hug P, Weidler PG,

Gehring AU (2000) Clays Clay Min 48:51]. Also, the catalysts with SiO2 exhibited severe line broadening in the XRD patterns compared to the catalysts without SiO2, indicating that the catalysts with SiO2 possess crystallites much smaller than the catalysts without SiO2. This also indicates that the incorporated SiO2 plays the role of spacer in the precipitated iron-based catalysts, which prevents hematite and ferrihydrite crystallites from sintering during the calcination treatment.

Figure S3. The H2-TPR profiles of the fresh catalysts (a) without copper promotion and (b) with copper promotion

Figure S3 shows the reduction behavior of the catalysts with and without copper promotion in the H2 atmosphere (H2-TPR). The chemical composition of the catalysts without copper promotion analyzed by XRF was 100Fe/17.3SiO2 in part per weight.

The catalysts without copper promotion exhibited broad reduction peaks at 331-465 C.

In contrast, the catalysts with copper promotion showed a sharp reduction peak below

290 C, which clearly shows the promotional effects of copper on the reduction behavior of iron-based catalysts.

Figure S4. The CO2-TPD profiles of the fresh catalysts: (a) AW and (b) AP

The surface basicity of the catalysts was analyzed by means of temperature programmed desorption using CO2 as an adsorbent (CO2-TPD). Figure S4 shows the

CO2-TPD profiles of AW and AP. The CO2-TPD profiles showed larger desorption peaks when the SiO2 was incorporated immediately after precipitation.