Promoter effects on iron-silica Fischer-Tropsch nanocatalysts: Conversion of carbon dioxide to lower olefins and hydrocarbons at atmospheric pressure

If CO2 hydrogenation is to become a viable process for the utilisation of CO2, improved catalysts are urgently needed. We report the promotional effects of Group 11 and 13 metals on the performance of iron–silica catalyst systems under atmospheric pressure. The addition of low loadings of gold resulted in a significant improvement in catalyst performance both in terms of conversion and selectivity to lower (C2–C4) olefins. Small loadings of indium proved highly effective for increasing CO2 conversion, whereas at higher loadings the selectivity to lower olefins could be dramatically increased. Catalysis tests involving palladium-promoted systems also proved successful with large increases in selectivity towards C5+ hydrocarbons observed. The catalysts were characterised by X-ray photoelectron spectroscopy, TEM and SEM, which confirmed the nanostructured nature of the catalytic species involved.