In–Ni Intermetallic Compounds Derived from Layered Double Hydroxides as Efficient Catalysts toward the Reverse Water Gas Shift Reaction

Intermetallic compounds (IMCs) are widely employed in heterogeneous catalysis. In this paper, the performance and mechanism of In–Ni IMCs with different structures (InNi3, InNi2, InNi, and In3Ni2) in the reverse water gas shift (RWGS) reaction are reported. In situ spectroscopic and microscopic characterizations combined with density functional theory (DFT) calculation demonstrated that the increase of the In/Ni ratio in IMCs enhanced the selectivity of CO by inhibiting the adsorption of CO* via "active site isolation." Ni, as the active site of the CO2 hydrogenation reaction, was isolated by In in In–Ni IMCs. Meanwhile, DFT calculation revealed that CO2 hydrogenation preferentially produced CO rather than CH4 and/or CH3OH, and the reaction path for the RWGS reaction is the redox path over the In–Ni IMC. At 500 °C, the catalyst achieved a 99.8% CO selectivity at a CO2 conversion of 50.7% for more than 250 h without any deactivation, rendering it a promising candidate for industrial application.