Breaking activity-selectivity-stability trade-offs in reverse water-gas shift reaction via high-energy micro-faceted Mo2N nanocrystals

The reverse water-gas shift reaction (RWGSR) is essential for converting CO 2 into fuels using renewable hydrogen, but it remains challenged by the difficulty of simultaneously maximizing catalyst activity, selectivity, and stability. These limitations stem from thermodynamic constraints – specifically, the Gibbs-Curie-Wulff theorem - which restricts the synthetic accessibility of high-energy micro-faceted nanocrystals via conventional methods. To address this, we introduce a near-surface “quasi-hyperbaric” ammonia strategy that integrates atmospheric-pressure processing with in-situ ammonia decomposition. This approach enables the controlled synthesis of molybdenum nitride nanocrystals with preferentially exposed high-energy (112) microfacets. These facets promote CO 2 activation through a hydrogen-assisted redox mechanism, driven by geometrically confined and stabilized Mo-N/M-O hybrid active sites. The resulting catalyst outperforms the benchmark Pt/CeO₂, which typically suffers from CO selectivity below 92%. Our catalyst achieves near-equilibrium conversion (56%) at a space velocity (24000 ml/g cat /h), with 100% CO selectivity and outstanding stability (≤ 1% deactivation over 250 hours).