Lattice-strained Na-ZnFe2O4 catalyst boosting CO2 hydrogenation to long-chain olefins

Abstract

Thermo-catalytic hydrogenation of CO₂ to fuels and chemicals is an effective way to utilize CO₂, but it faces significant challenges due to low CO₂ conversion and product selectivity. Here, we report a lattice-strained FeZnNa catalyst synthesized via a mechanochemical method (FeZnNa-G), showing a high selectivity for C₄₊ long-chain olefins (C₄₊⁼) of 64.9% and C₂₊⁼ of 77.5% at a high CO₂ conversion rate of 47.7%. We found that the lattice-contracted FeZnNa-G catalyst forms Na-enriched ZnO nano-islands on the surface after activation and a Na-ZnO/Fe₅C₂ structure with the presence of 97% Fe₅C₂, facilitating the formation of an HCOO* intermediate and enhancing CO₂ activation. A high C₄₊⁼ space–time yield (STY) of 474.9 mg g_cat⁻¹·h⁻¹ and an extremely low CO selectivity of ∼9.1% exhibited dual-high performance, significantly surpassing that in previous reports. This use of a lattice-strained catalyst offers a new strategy for the efficient conversion of CO₂ into high-value olefins, and paves the way for potential industrial applications.