Effect of Ru Doping on the Performance of Na‐Promoted Co/TiO₂ Catalysts for Direct CO₂ Hydrogenation to Fuels

The direct conversion of CO 2 into fuels via hydrogenation represents a promising solution to the storage of renewable energy. This reaction generally proceeds through the reverse water gas shift (RWGS) reaction to produce CO and the subsequent CO‐Fischer–Tropsch synthesis (FTS). On Co‐based catalysts, the introduction of dopants can improve CO 2 activation, enhance the RWGS activity, and decrease the methanation reaction. We reported that Na‐promoted Co/TiO 2 catalysts outperform the unpromoted ones in terms of activity and selectivity toward C 2+ . To further improve the catalytic performances, we doped a Na‐promoted Co/TiO 2 catalyst with ruthenium, which is known to favor a high degree of cobalt reduction in CO‐FTS. The effect of Ru location in relation to cobalt was investigated by using bimetallic and mixtures of monometallic catalysts. This study demonstrates that Ru doping leads to an improvement in catalytic activity. Furthermore, we show that the proximity between Co and Ru has a pronounced effect on the selectivity. The best configuration to achieve higher CO 2 conversion and C 5+ selectivity is obtained using mixtures of monometallic catalysts separated in two beds. Reducing the Ru loading significantly improved the selectivity toward C 2 ‐C 4 hydrocarbons.