While conventional InNi alloy phases in supported Ni/In2O3 catalysts show limited performance for CO2-to-methanol hydrogenation, we demonstrate that carbon incorporation into the InNi3 gives rise to a distinct catalytic architecture. The saturated InNi3C0.5 exhibits better catalytic stability and 40-fold enhanced methanol productivity compared with noncarburized alloys. Although the in situ carburization of InNi3 in the CO2 hydrogenation reaction produced the unsaturated InNi3Cx, this catalyst had lower stability and activity compared to the saturated InNi3C0.5. Structural degradation mechanisms reveal atmosphere-dependent intermetallic carbon oxidation pathways in the InNi carbides. Furthermore, hierarchical engineering through an electrostatic assembly of the saturated InNi3C0.5 hexagonal nanosheets on In2O3 hollow nanotubes synergistically enhances both activity and durability. Density functional theory analysis unveils that carbon-induced electron redistribution creates Ni/C cooperation resembling uniform electron gas behavior, simultaneously optimizing hydrogenation capacity and oxygen vacancy dynamics on the oxide support. This work establishes intermetallic carbon saturation engineering as a general strategy for upgrading intermetallic catalysts in renewable fuel synthesis.
Cai et al. (Thu,) studied this question.