Construction and engineering of an interfacial structure in a Cux/FeMgOy catalyst for the photoreduction of CO2 to ethylene

Abstract

An FeMgO_y-modified Cu interfacial structure is constructed as a photocatalyst for CO₂ conversion with H₂O via the structural topological transformation of layered double hydroxides. By changing the Cu/Fe ratio, the nature of the interfacial structure is engineered, in which Cu₁/Fe₁MgO_y exhibits enhanced catalytic behavior. The total consumed electron number could reach 209.2 μmol g⁻¹ h⁻¹, while a selectivity of 18.9% and an evolution rate of 9.9 μmol g⁻¹ h⁻¹ for CO₂ reduction to C₂H₄ are achieved, with a CO evolution rate of 40.1 μmol g⁻¹ h⁻¹ under simulated sunlight. The formation of Cu₁^δ−–Fe₁^δ+MgO_y reactive sites not only facilitates the efficient electron–hole pair separation, thus promoting the multielectron reduction for the C–C coupling process, but also improves the CO₂ adsorption ability, confirmed by X-ray photoelectron spectroscopy, photoluminescence spectroscopy and in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) analysis. The catalytic mechanism is revealed by in situ IR spectroscopy. This study offers a route to construct and engineer a highly efficient interfacial catalyst for CO₂ conversion.