A specific defect type of Cu active site to suppress Water-Gas-Shift reaction in syngas conversion to methanol over Cu catalysts

[Display omitted] •The role of Cu active type with the point, flatted line and stepped line defects in syngas conversion were unraveled.•A specific defect type of Cu active site is proposed to facilitate methanol and suppress WGSR.•Methanol /WGSR activity presents a volcano-shaped curve with GCN/d-band center of Cu active site.•Cu(111)PD is screened out to exhibit the highest methanol activity and better selectivity.•Cu(111)PD corresponds to the moderate GCN (6.250) and d-band center (−2.42 eV). Inspired by the sensitivity of methanol and WGSR to Cu active site types, a specific defect type of Cu active site is proposed to facilitate methanol synthesis and effectively suppress WGSR to produce CO2. In this work, DFT calculations is implemented to investigate the detailed mechanism of syngas-to-methanol and WGSR over Cu catalysts including Cu active type with the point, flatted line, and stepped line defects. The results suggested that WGSR can be regulated by tuning the adsorption and dissociation ability of H2O over different Cu active sites to decrease CO2 selectivity. The relationship of GCN value and d-band center of active center with the activity of methanol and WGSR was proposed to screen out high-performance catalysts. This study provides theoretical basis for designing and optimizing Cu-based catalysts to suppress WGSR leading to lower CO2 selectivity by adjusting Cu active site to meet a specific defect type.