This work focuses on Ga promotion to Co sites in supported CoGa catalysts on CO insertion and C-C coupling in syngas conversion. The CoGa catalysts were developed in our group for syngas conversion; they possess uniform dispersion of CoGa particles and pseudo-homogeneous distribution of Co and Ga elements. The Ga atoms contiguous to Co atoms not only contributed to isolating Co centers but also donated electrons to neighboring Co sites. The isolated Co sites were responsible for linearly nondissociative CO adsorption, boosting the CO insertion step to afford alcohol products. Electronic donation from Ga to Co sites promoted dissociative CO adsorption, enhancing carbon-chain growth. The match of CO insertion and C-C coupling gave rise to both enhanced activity in the syngas conversion and impressive selectivity to ethanol and higher alcohols. (C) 2017 Published by Elsevier Inc.