Manipulation of CO2 hydrogenation selectivity over RuSn/La2O2CO3 catalysts with intermetallic electron transfer

Abstract

Selective hydrogenation of CO2 to syngas via the reverse water–gas shift (RWGS) route provides an effective strategy to achieve low-carbon development. While CO2 methanation to CH4 takes place readily on Ru metal, the selective hydrogenation of CO2 to CO in Ru-catalysts remains a challenge. In this work, we prepared a Ru-Sn/La2O2CO3 catalytic system allowing over 99% selectivity of CO during CO2 hydrogenation at 400 °C. Characterization revealed that the transfer of electrons from Sn to Ru weakened the dissociation ability of H2 while improving the adsorption ability of O on Ru. The former inhibited the formation of methane, while the latter caused the C-O bond energy of CO2 adsorbed at the Ru-Sn interface to decrease and dissociate at the Ru-side, forming Ru-CO* and Ru-O*; thus, realizing the RWGS process. An ultra-low Ru-loaded (0.01 wt%) RuSn/La2O2CO3 catalyst with strong metal-support interactions achieved a CO2 hydrogenation rate at 103 times higher than the best reported data. This catalyst was successfully applied to the hydrogenation of blast furnace gas (BFG) to syngas, showing a CO formation rate as high as 2.3*106 mmolCO·gRu−1·h−1 and remaining stable at 850 °C for 1000 h.