Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift (RWGS) reaction,however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product.In this work,a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster (the average size as small as 0.5 nm) is prepared via a facile carbothermal treatment for highly selective CO2-CO reduction.The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis,for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor.The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μmol gMo2c-1s-1 at 400 ℃ with a superior selectivity toward CO (＞ 99.5％).This work highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.