An innovative Cu(X)@NH2-UiO-68 heterojunction designed for enhanced CO2 photocatalytic conversion: amplification via bimetallic Zr/Cu centers

• Engineered bimetallic Zr–O–Cu sites within UiO-68 MOFs enabled the photocatalytic CO₂ reduction to C₂ products for the first time. • Achieved high selectivity for C₂H₆, outperforming all other UiO-type MOFs. • Polarized Zr-O-Cu sites boost light capture and charge separation for efficient catalysis. • Novel strategy for selective C C coupling in MOFs for sustainable carbon valorization. Metal-organic frameworks (MOFs) photocatalysis CO 2 reduction reaction (PCRR) to fine chemicals represents as a promising avenue for sustainable carbon resources. However, in this transformation, selective synthesis of C 2 products like C 2 H 6 remains challenge due to limited efficiency in multiple electron transfer processes and inappropriate active sites. Herein, to address this challenge we engineered an oxo-bridged bimetallic sites, Zr‒O‒Cu, within the framework of UiO-68 MOFs through cation exchange mechanism between the installed Zr nodes and Cu salt. The resulted in photocatalysts (designated as Cu(X)@NH 2 -UiO-68) demonstrated significant photocatalytic activity by producing 51.3 µmolh −1 g −1 of C 2 H 6 with remarkable selectivity under free-photosensitizer condition. A review of the literature indicates that Cu(9)@NH 2 -UiO-68 demonstrates superior photocatalytic activity compared to all other UiO-type MOFs reported to date and is one of the most efficient MOF photocatalysts in this regard. In-depth characterization demonstrated that the development of polarized Zr‒O‒Cu active sites plays a critical role in enhancing light capture, facilitating charge migration and separation, and diminishing the band gap energy. This engineering methodology offers crucial insights into the production of C 2 ​fuels within UiO-68 MOFs.