Photocatalytic Synergy Between α-BiO Nanosphere and Spindle MIL-88A for Gas-Phase CO Reduction.

Visible light-active photocatalysts play a crucial role in gas-phase photocatalytic CO reduction, offering significant potential for sustainable energy conversion. Herein, we present the synthesis of spindle-shaped Iron (Fe)-based metal-organic framework (MOF) MIL-88 A, coupled with distinct α-BiO nanospheres. The α-BiO/MIL88A heterostructure is formed by interacting opposite surface charges, enhancing visible-light absorption and efficient interfacial charge-carrier separation. Such low-cost photocatalysts have a 1.75 eV band gap and demonstrate enhanced efficacy in converting CO to CO, CH, and H in water without using any sacrificial agents or noble metals compared to pristine MIL88A. In addition, in-situ Electron Spin Resonance (ESR) analyses revealed that these unique catalysts combination promoted enhanced interfacial charge dynamics, creating efficient trapping sites for photogenerated carriers. Further, in-situ Diffuse Reflectance Infrared Fourier Transfer Spectroscopy (DRIFTS) investigation elucidates the plausible reaction mechanism and provides an effective methodology for catalyst screening for CO photoreduction. This study offers an effective approach for synthesizing the earth-abundant heterostructure from metal oxide and low-cost MOFs, enhancing photocatalytic activity for sustainable carbon dioxide conversion into invaluable chemicals.