Among higher alcohol synthesis (HAS) catalysts, Rh-based catalysts show catalytic activity for the selective production of ethanol and C2+ oxygenates, because both CO dissociation and CO insertion are available on the surface of Rh. Theoretical studies have indicated that the activation barrier of CO on the Rh(100) surface is lower than other Rh surfaces, and this can lead to higher catalytic activity for HAS on Rh-based catalysts. Uniform and specifically size-controlled Rh nanocubes (NCs) with Rh(100) planes were prepared via a polyol synthesis route, and introduced onto ordered mesoporous carbon (OMC) supports. The Rh NC/OMC materials were employed for HAS from syngas to investigate the effect of the Rh crystal surface. TEM analysis and catalytic reactions clearly demonstrated that Rh NCs in the OMC support can improve the catalytic performance for HAS by both enhancing CO dissociation and suppressing methane formation. Moreover, additional chain growth reactions for the synthesis of C₃ and C₄ alcohols were induced by the Rh NCs on OMC supports.