Carbon-Aerogel-Confined MoO<sub>2</sub> as a Robust Nanocatalyst for the Reverse Water-Gas Shift Reaction.

Rafique, Muhammad Umer; Cui, Pengfei; Jia, Wenyu; Hussain, Zahid; Wang, Yuxuan; Rana, Zohaib; Xiang, Guolei · Nano Lett · 2026

basic_science · Level V

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Abstract

Converting CO<sub>2</sub> 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 (Mo<sub>2</sub>C) widely regarded as the true active species due to the <i>in situ</i> carburization of MoO<sub><i>x</i></sub> under reaction conditions. Here, we demonstrate that MoO<sub>2</sub> 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 MoO<sub>2</sub> after the stability test at 500 °C for 200 h; in contrast, pure MoO<sub>2</sub> nanoparticles start to transform into metallic Mo under the same reaction conditions. This discovery differs from the prevailing argument that MoO<sub><i>x</i></sub> is the precursor to carbides in high-temperature RWGS, highlighting the role of interfacial confinement in stabilizing nanocatalysts.