Cu₂O-catalyzed C₂H₂ selective hydrogenation: Use of S for efficiently enhancing C₂H₄ selectivity and reducing the formation of green oil precursor

Development of cost-effective catalysts with high activity and selectivity toward C₂H₂ hydrogenation to gas C₂H₄ is challenging. This research found that the challenge could be overcome using S inherently existing in the raw material for production of C₂H₄ and conventionally considered as a catalyst poison. Specifically, the sulfur-containing Cu₂O catalysts are superior to the sulfur-free Cu₂O catalysts in two dimensions, one is the improvement of C₂H₄ formation activity and selectivity; the other is to reduce green oil precursor formation. The microscopic mechanism of S lies in blocking larger active region required for C₂H₂ polymerization and C₂H₄ hydrogenation to ethane; whereas without affecting smaller active region needed for C₂H₂ hydrogenation to C₂H₄. Namely, the S atom modified Cu₂O surface morphology, change the spatial scale of active region for associated reactions, and control the formation of desired products. Thus, the sulfur-containing Cu₂O catalysts are potentially promising candidates for C₂H₂ hydrogenation to C₂H₄.