<p>Online Resource 1</p><p>Elemental mapping</p><p>The chemical homogeneity of samples was checked using elemental mapping analysis on the</p><p> calcined catalyst. Elemental mapping images corresponding to elemental distribution of Co, Mg, Al and O</p><p> over the catalysts with the highest and lowest amount of Al3+, i.e., Co/HT15 and Co/HT51 catalysts are</p><p> shown in Fig. 8. As can be seen in these representative micrographs, the applied Co 2+ wet impregnation</p><p> method and the relatively low calcination temperature (i.e., 300 °C) were appropriate to obtain a</p><p> homogeneous cobalt distribution on Mg-Al mixed oxide hydrotalcite-derived support. In contrast with the</p><p> cobalt homogeneous distribution, the presence of bright zones in the micrograph corresponding to the Al-</p><p> mapping image for the Co/HT15 catalyst would suggest the existence some segregated Al-rich phase were</p><p> formed in addition to Mg-Al hydrotalcites, during the co-precipitation synthesis process of Mg-Al</p><p> hydrotalcites, particularly at low Mg/Al molar ratio (≤ 0.3). </p><p>Fig 8. Elemental Co, Mg, Al and O distribution mapping images in calcined cobalt-based catalysts. a) Co/HT15, and b) Co/HT51.</p><p>Thermogravimetric analysis</p><p>The decomposition profiles of the cobalt-based catalysts calcined at 300 °C are shown in Fig 9. Co/HT-</p><p>MG70 and Co/HTXY with molar ratio of 5, 3 and 1 catalysts presented a similar TGA profile. As concluded</p><p> from XRD results, the hydrotalcite structure can regenerate as a consequence of the re-adsorption of CO 2 and H2O. The TGA profiles of the calcined catalysts also suggest a reconstruction of the hydrotalcite phase.</p><p>Therefore, the first step below 250 °C corresponds to the loss of the water gained by rehydration, while the</p><p> second (250 – 500 °C) arises from the decomposition of the hydroxide layers and carbonate anions</p><p> remaining after calcination and formed by CO2 re-adsorption. </p><p>Fig 9. TGA profiles of the calcined cobalt-based catalysts: Co/HT15 (black), Co/HT13 (red), Co/HT11</p><p>(blue), Co/HT31 (magenta), Co/HT51 (violet), Co/MgO (green), Co/HT-MG70 (brown). </p><p>On the other hand, Al-rich hydrotalcites, i.e., Co/HT13 and Co/HT15 catalysts showed different</p><p> decomposition profiles. In this case, two weight losses below 160 °C and between 150 – 500 °C were</p><p> observed, with the second step characterized by a smoother curve. Taking into account the results from</p><p>XRD analysis, the first step around 150 °C in these two samples can be associated to the loss of water and</p><p> the second one to the loss of the OH- groups bonded to Al3+ in the hydrotalcite and boehmite phases, along</p><p> with the decarbonation. Finally, the TGA profile Co/MgO shows a slight first weight loss (< 150 °C)</p><p> attributed to dehydration and a marked second loss (150 - 650 °C), which could be associated to</p><p> deshydroxylation and decarbonation of nesquehonite phase (MgCO3·3H2O). </p>