Ni‐BDC MOF/MnO ₂ Composite for Highly Efficient CO ₂ Photoreduction to CO and CH ₄ Under Visible Light

Abstract MOF‐based composites with semiconductors offer synergistic effects, such as broader light absorption, improved charge carrier separation, and more active catalytic sites, all of which enhance the overall performance of the MOFs in CO 2 reduction. This study presents the development and characterization of a Ni‐BDC MOF/MnO 2 composite for photocatalytic CO 2 reduction under visible light. The Ni‐BDC MOF with a bandgap of 3.16 eV was integrated with γ‐MnO 2 , a visible light‐absorbing semiconductor to improve charge separation and extend light absorption. The resulting composite exhibited a reduced bandgap of 2.7 eV, enabling efficient CO 2 reduction to CO and CH 4 . Structural, optical, and electrochemical analyses confirmed the intimate interaction between Ni‐BDC MOF and MnO 2 , enhancing charge carrier dynamics. The optimized composite achieved high yields of CO (56.97 µmol g⁻¹) and CH 4 (23.5 µmol g⁻¹) after 6 h of irradiation, with enhanced stability and minimal electron‐hole recombination. The mechanistic study revealed multiple intermediates involved in CO 2 reduction, providing insights into the pathways for CO and CH 4 formation. This work offers a sustainable approach to CO 2 conversion with potential applications in greenhouse gas mitigation and energy production.