Density functional theory study of Cu based catalysts with sulfur modification for the selective conversion of syngas to C2 oxygenates

Abstract

Low-cost catalysts based on Cu have emerged as promising catalysts for synthesizing ethanol from syngas, despite their limited selectivity to ethanol. This study investigates sulfur-modified Cu(100) surface for converting syngas to C2 oxygenates, and explores the intricate mechanism of C2 oxygenates formation from CO hydrogenation using density functional theory (DFT) calculations. The findings indicate that the CH2 and CH3 are the most advantageous monomers over other CHx (x = 1–3) intermediates, surpassing methanol and methane formation. This result significantly differs from observations on the Cu(100) surface. For C2 oxygenates formation, the most effective pathway involves the insertion of CHO into CH3 or CHO via C–C to generate a stable intermediate CH3CHO and OHCCHO on the S-Cu(100) surface. Additionally, the examination of electrical and structural characteristics reveals a mild charge transfer between Cu and S, which enhances the catalytic performance for syngas to C2 oxygenates. Therefore, this work provides valuable insights into the role of sulfur-modified Cu(100) surface in enhancing the selectivity to C2 oxygenates.