UiO66-NH2@In2O3 heterostructures for improved photocatalytic CO2 reduction†

Abstract

The development of highly efficient photocatalysts for CO₂ reduction remains a critical challenge in achieving sustainable energy conversion. In this study, we report the synthesis of a UiO66-NH₂@In₂O₃, integrating UiO66-NH₂ metal organic frameworks (MOFs) with indium oxide (In₂O₃) nanoparticles, forming a robust heterostructure. Characterization results demonstrated that calcination at 250 °C for 4 hours yielded a heterostructure with indium uniformly incorporated, as confirmed by XRD, SEM, TEM and ICP-OES analyses. XPS studies revealed significant electronic interactions between UiO66-NH₂ and In₂O₃, including shifts in binding energies of indium and zirconium, indicative of chemical bonding. This heterostructure facilitated enhanced charge separation and transfer, as evidenced by photocurrent measurements, leading to superior photocatalytic CO₂ reduction performance. Under light irradiation, UiO66-NH₂@In₂O₃ achieved a CO production rate of 83.68 μmol g⁻¹ during the first hour and a cumulative yield of 485.08 μmol g⁻¹ after 7 hours, significantly outperforming pristine UiO66-NH₂ and In₂O₃. The superior activity is attributed to the large surface area of UiO66-NH₂, facilitating CO₂ adsorption, and the heterojunction formation with In₂O₃, enhancing charge carrier dynamics. These findings highlight the synergistic effects of UiO66-NH₂ and In₂O₃, providing insights into the design of advanced photocatalysts for environmental and energy applications.