In-Situ Dynamic Carburization of Mo Oxide with Unprecedented High CO Formation Rate in Reverse Water-Gas Shift...

In situ construction of active structure under reaction conditions is highly desired but still remains challenging in many important catalytic processes. Herein, we observe structural evolution of molybdenum oxide (MoO_x) into highly active molybdenum carbide (MoC_x) during reverse water-gas shift (RWGS) reaction. Surface oxygen atoms in various Mo-based catalysts are removed in H₂-containing atmospheres and then carbon atoms can accumulate on surface to form MoC_x phase with the RWGS reaction going on, both of which are enhanced by the presence of intercalated H species or Pt-dopants in MoO_x. The structural evolution from MoO_x to MoC_x is accompanied by enhanced CO₂ conversion, which is positively correlated with the surface C/Mo ratio but negatively with the surface O/Mo ratio. As a result, an unprecedented CO formation rate of 7544.6 mmol ⋅ g_catal ^-1 ⋅ h^-1 at 600 °C has been achieved over in situ carbonized H-intercalated MoO₃ catalyst, which is even higher than those from noble metal catalysts. During 100 h stability test only a minimal deactivation rate of 2.3 % is observed.