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

Abstract 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.