The conversion of carbon monoxide into value-added liquid alcohols has recently attracted considerable attention (Li et al., 2014; De Luna et al., 2018; Pang et al., 2019). However, the ongoing reports for novel catalysts possessing excellent efficiency are still rare due to the high barriers of the reactions involved in the upgradation of the carbon-chains. Cu delta+ sites have been found to promote multi-carbon products, whereas the long-term stability of Cu delta+ sites under reduction conditions remains a challenge for copper-based catalysts. Here, we demonstrate a Mott-Schottky catalyst composed of a copper trimer and the newly synthesized holey C2N semiconductor to stabilize the Cu delta+ sites. The formed metal semiconductor Schottky barrier promotes electron transfer from the Cu-3 cluster to the semiconducting C2N substrate and retains the Cu trimer oxidation state throughout the reaction. The Cu-3@C2N catalyst exhibits significantly promoted C-C bond formation and hydrogenation activity that outperforms Cu (1 1 1) and Cu (1 00) surfaces. In addition, we screened various possible intermediates and provided a plausible thermodynamic reaction pathway for producing n-propanol with a limiting potential of only 0.53 V. Our work offers a promising strategy to maintain the oxidation state of metal sites during the el ectroca ta lysi s. (C) 2019 Elsevier Inc. All rights reserved.