Supplementary. Figure 1 TGA profile of materials under air flow (100 ml min -1 NTP,

Transcription

1 Supplementary Figure 1 TGA profile of Fe@C materials under air flow (1 ml min -1 NTP, heating rate 1 K min -1 ).

2 Supplementary Figure 2 Nitrogen adsorption-desorption isotherms at 777 K: effect addition on the textural properties of Fe@C. Label numbers indicate the weight% Fe sample. of FA in the

3 Supplementary Figure 3 A) HAADF micrograph of 38-Fe@C and B) Fe EDX mapping.

4 k 3 (k) (R) (Å -4 ) K k 3 (k) k 3 (k) k 3 (k) k (Å -1 ) Supplementary Figure 4 al (black) and simulated (red, dashed) EXAFS spectra k (left) and R (right) space top to bottom: Basolite F- 3 at 498 K; Fe@C at 723 K; Fe@C reduced at 673 K by H 2 /He (1 vol. %, 1 bar); Fe@C after 5 h Fischer-Tropsch conditions (613 K, CO/H 2 =1, 1 bar). (R) (Å -4 ) (R) (Å -4 ) (R) (Å -4 ) K 673 K, H K, FTS R (Å)

5 Supplementary Figure 5 Time dependent DRIFTS spectra during adsorption of 5% v/v CO/He at room temperature on 31-Fe@C. Besides the P- and R- branches of the vibration-rotation spectrum of CO in the gas phase, additional bands are present at 236 and 1913 cm -1, corresponding to side-on and bridge adsorption of CO respectively, on metallic iron and/ /or iron carbides (Fe x C).

6 Supplementary Figure 6 Fe2p core level spectra of 31-Fe@C and 25-Fe@C. The main bands at ev and ev indicate the presence of Fe 3 O 4, while the sharp peaks at about ev (Fe2p 3/2 ) and ev (Fe2p 1/2 ) are assigned to Fe x C species. 1-3 No metallic Fe is evident from the Fe2p 3/2 and Fe2p 1/2 spectra, in agreement with Mössbauer studies. Focusing on the Fe carbide phase region (77 ev and 72 ev), slightly lower binding energies (.4 ev) are found for samples prepared with higher FA loadings, which may suggest the formation of different carbide species. For example, Fe 5 C 2 has a binding energy of 77.3 ev, while for other carbides with a more covalent character lower binding energies are found (e.g., 76.9 ev).

7 Supplementary Figure 7 O1s core level XPS spectra: A) 25-Fe@C and B) 31-Fe@C. XPS measurements were performed on a K-alpha Thermo Fisher Scientific spectrometer using monochromatic Al Kα X-ray source. In both cases, three different surface oxygen species can be identified: the band at ev is characteristic of Fe oxide phases (in this case Fe 3 O 4 ), while the higher binding energy bands around and ev correspond to surface oxygen groups C=O and COO, respectively. The furfuryl loading significantly increases the O/Fe ratio, as well as the relative amount of oxygen groups on the surface of the porous carbon. For example, on 25-Fe@C the relative percentage of oxygen groups is about 78%, while on 31-Fe@C it decreases to 68%.

8 Supplementary Figure 8 Time on stream evolution of conversion during FTS (A) and Carbon selectivity of FTS products after 9 h TOS (B). Reaction conditions: 613 K, 2 bar, H 2 /CO = 1, and GHSV of 3, h -1 (space velocity based on catalyst bed volume).

9 Supplementary Figure 9 Time-on-stream evolution of CO conversion for the un-promoted 38- catalyst. Reaction conditions: 613 K, 2 bar, H 2 /CO = 1, and GHSV of 7, h -1 (space velocity based on catalyst bed volume). No deactivation was observed during 22 h under these reaction conditions.

10 Supplementary Figure 1 FTS performance of Fe@C obtained from the pyrolysis of Basolite F- 3 at 773 and 873 K. Carbon conversion (A) and selectivity to methane (B) as a function of time on stream (TOS).

11 Supplementary Figure 11 ASF distribution plot (logarithm of the molar fraction y n of the C n component in the product versus n) for un-promoted and promoted 38-Fe@C after 1 h TOS at 613 K, 2 bar total pressure, H 2 /CO= 1 and GHSV of 3, h -1.

12 Supplementary Table 1 CO conversion and carbon selectivity to products over Fe@C after 9 h TOS at 613 K, 2 bar total pressure, feed composition H 2 /CO =1 and GHSV of 3, h -1 space velocity. Sample X / % S / % C1 C2=-C5= C2-C5 CO 2 C2=/C2 C3=/C3 25-Fe@C Fe@C Fe@C Fe@C

13 Supplementary Table 2 FTS performance on un-promoted Fe@C: Effect of particle size Precursor Temperature K d nm Fe wt% X % FTY TOF CH mol g Fe s -1 s -1 % 1 h 9 h 1 h 9h 1 h 9h 1 h 9 h Basolite F CO conversion (%), carbon selectivity (%) and molar fraction (-) of each product were defined as explained below: X CO F in,co F F in,co out,co 1 S Cn F CO2 nf Cn N n 1 nf Cn 1 y Cn Cn N FC n n 1 Catalytic activity is expressed as Fe time yield (FTY), defined as the number of CO moles converted to hydrocarbons per gram of Fe per second. The apparent TOF was also calculated for some catalysts with known metal dispersion and were obtained from the following expression: F,..