(726c) PdPt Alloy "Nanoclams" for CO2 Reduction in Tandem with Microbial Communities to Maximize Faradaic Efficiency to Value-Added Products
The PdPt nanoclams have a unique tapered morphology that combines high surface area with exposure of numerous undercoordinated sites for CO2 reduction with activity exceeding that of either Pd or Pt for CO2 reduction to formate at 0.2 V vs RHE, which is a provocative result. In comparison with bulk Pd, PdPt, and Pt systems, we find that the interplay of multiple trends affect selectivity and activity:
- Increasing Pt content shifts selectivity from formation of formate to hydrogen evolution in the bulk
- Increasing Pt content increases overall activity and prevents catalyst deactivation while changing the energetics of hydride intercalation into PdPt
- Nanostructured morphology of PdPt nanoclams increases selectivity to formate in PdPt nanoclams vs in bulk, planar PdPt.
Understanding the performance of PdPt for CO2 reduction can lead to design principles that can inform the discovery of new classes of alloy catalyst with improved activity for CO2 reduction.
In addition to this understanding, we report our results on the creation of a hybrid electrochemical-biological CO2 reduction system in which formate and hydrogen are produced through electrochemical CO2 reduction by PdPt nanoclams. These products are metabolized by methanogens in combination with CO2 to yield ~100% faradaic efficiency to methane. Going forward, the integration of microbial communities with these nanostructured PdPt catalysts has the potential to combine the best-of-both-worlds from electrochemical and biological systems to achieve a regenerative catalytic system with high-selectivity, high activity, and low overpotential.