Synthesis of Long-chain Paraffins over Bimetallic Na–Fe0.9Mg0.1Ox by Direct CO2 Hydrogenation

Abstract

Direct CO₂ hydrogenation into long-chain hydrocarbons over iron catalysts is considered the most promising approach to mitigate global warming issues. However, iron catalysts typically produce olefin-rich hydrocarbons, which make it difficult to directly use them as liquid transportation fuels. Here, we present a bimetallic Na–Fe_0.9Mg_0.1O_x catalyst that produced paraffin-rich long-chain hydrocarbons with a high C₅₊ yield of 17.9% at a high CO₂ conversion of 42.1%. The formation of oxygen vacant sites at the catalyst surface and electron transfer from MgO to Fe phase increased the reducibility of Fe₃O₄ to α–Fe. In addition, the presence of MgO increased the H₂ and CO₂ adsorption and facilitated the C–C coupling reaction to produce long-chain paraffins. The high CO₂ conversion, high C₅₊ yield, and paraffin-rich products make Fe_0.9Mg_0.1O_x a highly promising catalyst to produce liquid transportation fuels under industry-relevant conditions.