A tailored multi-functional catalyst for ultra-efficient styrene production under a cyclic redox scheme

Abstract

Styrene is an important commodity chemical that is highly energy and CO₂ intensive to produce. We report a redox oxidative dehydrogenation (redox-ODH) strategy to efficiently produce styrene. Facilitated by a multifunctional (Ca/Mn)_1−xO@KFeO₂ core-shell redox catalyst which acts as (i) a heterogeneous catalyst, (ii) an oxygen separation agent, and (iii) a selective hydrogen combustion material, redox-ODH auto-thermally converts ethylbenzene to styrene with up to 97% single-pass conversion and >94% selectivity. This represents a 72% yield increase compared to commercial dehydrogenation on a relative basis, leading to 82% energy savings and 79% CO₂ emission reduction. The redox catalyst is composed of a catalytically active KFeO₂ shell and a (Ca/Mn)_1−xO core for reversible lattice oxygen storage and donation. The lattice oxygen donation from (Ca/Mn)_1−xO sacrificially stabilizes Fe³⁺ in the shell to maintain high catalytic activity and coke resistance. From a practical standpoint, the redox catalyst exhibits excellent long-term performance under industrially compatible conditions.