In Situ Observation of C-C Coupling and Step Poisoning During the Growth of Hydrocarbon Chains on Ni(111)

The synthesis of high-value fuels and plastics starting from small hydrocarbon molecules plays a central role in the current transition towards renewable energy. However, the detailed mechanisms driving the growth of hydrocarbon chains remain to a large extent unknown. Here we investigated the formation of hydrocarbon chains resulting from acetylene polymerization on a Ni(111) model catalyst surface. Exploiting X-ray photoelectron spectroscopy up to near-ambient pressures, the intermediate species and reaction products have been identified. Complementary in situ scanning tunneling microscopy observations shed light onto the C-C coupling mechanism. While the step edges of the metal catalyst are commonly assumed to be the active sites for the C-C coupling, we showed that the polymerization occurs instead on the flat terraces of the metallic surface.

Automated summary

The mechanism behind the growth of hydrocarbon chains during the synthesis of high-value fuels and plastics from small hydrocarbon molecules remains largely unknown. In this study, the formation of hydrocarbon chains resulting from acetylene polymerization on a Ni(111) model catalyst surface was investigated using X-ray photoelectron spectroscopy at near-ambient pressures. The intermediate species and reaction products were identified, and in situ scanning tunneling microscopy observations provided insights into the C-C coupling mechanism. The study revealed that polymerization occurs on the flat terraces of the metallic surface instead of the step edges commonly assumed as the active sites for C-C coupling.