Light‐Assisted CO ₂ Hydrogenation over Pd ₃ Cu@UiO‐66 Promoted by Active Sites in Close Proximity

TLDR: In this article , tiny Pd3 Cu nanoparticles are confined into a metal-organic framework (MOF), UiO-66, to afford a methanol production rate of 340 μmol g-1 h-1 at 200 °C and 1.25 MPa under light irradiation, far surpassing that in the dark.

Abstract: CO2 hydrogenation to methanol has attracted great interest while suffering from low conversion and high energy input. Herein, tiny Pd3 Cu nanoparticles are confined into a metal-organic framework (MOF), UiO-66, to afford Pd3 Cu@UiO-66 for CO2 hydrogenation. Remarkably, it achieves a methanol production rate of 340 μmol g-1 h-1 at 200 °C and 1.25 MPa under light irradiation, far surpassing that in the dark. The photo-generated electron transfer from the MOF to antibonding orbitals of CO2 * promotes CO2 activation and HCOO* formation. In addition, the Pd3 Cu microenvironment plays a critical role in CO2 hydrogenation. In contrast to the MOF-supported Pd3 Cu (Pd3 Cu/UiO-66), the Pd3 Cu@UiO-66 exhibits a much higher methanol production rate due to the close proximity between CO2 and H2 activation sites, which greatly facilitates their interaction and conversion. This work provides a new avenue to the integration of solar and thermal energy for efficient CO2 hydrogenation under moderate conditions.