1 research outputs found
Role of Manganese Oxide in Syngas Conversion to Light Olefins
The
key of syngas (a mixture of CO and H<sub>2</sub>) chemistry
lies in controlled dissociative activation of CO and C–C coupling.
We demonstrate here that a bifunctional catalyst of partially reducible
manganese oxide in combination with SAPO-34 catalyzes the selective
formation of light olefins, which validates the generality of the
OX-ZEO (oxide-zeolite) concept for syngas conversion. Results from
in situ ambient-pressure X-ray photoelectron spectroscopy, infrared
spectroscopy, and temperature-programmed surface reactions reveal
the critical role of oxygen vacancies on the oxide surface, where
CO dissociates and is converted into surface carbonate and carbon
species. They are converted to CO<sub>2</sub> and CH<sub><i>x</i></sub> in the presence of H<sub>2</sub>. The limited C–C coupling
and hydrogenation activities of MnO enable the reaction selectivity
to be controlled by the confined pores of SAPO-34. Thus, a selectivity
of light olefins up to 80% is achieved, far beyond the limitation
of Anderson–Shultz–Flory distribution. These findings
open up possibilities to explore other active metal oxides for more
efficient syngas conversion