Carbon-Aerogel-Confined MoO2 as a Robust Nanocatalyst for the Reverse Water-Gas Shift Reaction.

Converting CO2 into syngas via the reverse water-gas shift (RWGS) reaction is promising for carbon cycling, but industrialization is critically dependent on developing efficient non-noble metal catalysts. Mo-based catalysts have been extensively investigated, with molybdenum carbide (Mo2C) widely regarded as the true active species due to the in situ carburization of MoOx under reaction conditions. Here, we demonstrate that MoO2 can act as an intrinsically active and stable RWGS catalyst when confined within the matrix of the carbon aerogel. The interface confinement effectively suppresses over-reduction and carburization of MoO2 after the stability test at 500 °C for 200 h; in contrast, pure MoO2 nanoparticles start to transform into metallic Mo under the same reaction conditions. This discovery differs from the prevailing argument that MoOx is the precursor to carbides in high-temperature RWGS, highlighting the role of interfacial confinement in stabilizing nanocatalysts.