Promoter Effects on Iron-Silica Fischer-Tropsch Nanocatalysts: Conversion of Carbon Dioxide to Lower Olefins and Hydrocarbons at Atmospheric Pressure

Abstract

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.

Keywords: carbon dioxide; gold; heterogeneous catalysis; indium; iron; nanoparticles.