Ionic-caged heterometallic bismuth-platinum complex exhibiting electrocatalytic CO₂ reduction.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Electrochemistry

Background:

• Development of efficient catalysts for carbon dioxide (CO2) reduction is crucial for addressing climate change.
• Heterometallic complexes offer unique electronic and structural properties for catalytic applications.
• Bismuth-platinum (Bi-Pt) interactions are underexplored in the context of CO2 electrocatalysis.

Purpose of the Study:

• To synthesize and characterize a novel air-stable heterometallic bismuth-platinum complex.
• To investigate the catalytic activity of the complex for CO2 reduction.
• To elucidate the mechanism of CO2 reduction using electrochemical and computational methods.

Main Methods:

• Synthesis and structural characterization of the [BiPt(SAc)5]n complex.
• Cyclic voltammetry (CV) and controlled potential electrolysis (CPE) for CO2 reduction studies.
• Natural bond orbital (NBO), local orbital locator (LOL), localized orbital bonding analysis (LOBA), X-ray absorption fine structure (XAFS), DFT calculations, and reflectance infrared spectroelectrochemistry.

Main Results:

• An air-stable heterometallic Bi-Pt complex, [BiPt(SAc)5]n, was successfully synthesized, confirming Bi-Pt bonding and an oxygen ionic cage around Bi.
• The complex demonstrated efficient electrocatalytic reduction of CO2 to CO with a high faradaic efficiency (92%) and turnover frequency (8 s-1).
• DFT calculations and spectroelectrochemical data supported a mechanism involving the ionic cage for energetically favored CO2 reduction.

Conclusions:

• The synthesized Bi-Pt complex is a highly effective electrocatalyst for CO2 to CO conversion.
• The unique structural features, including the Bi-Pt bond and ionic cage, play a critical role in the catalytic activity.
• This study presents a promising new material and mechanistic insight for CO2 utilization technologies.