Nanoporous PdSnBi alloys for superior formic acid oxidation electrocatalysis

Abstract

The application of direct formic acid fuel cells (DFAFCs) is restricted by the toxicological effect of reaction intermediates (especially CO) on the surface of the catalyst during the formic acid oxidation reaction (FAOR) process. As a result, designing FAOR catalysts with superior anti-toxicity is of vital importance. In this paper, a PdSnBi trimetallic alloy catalyst has been successfully prepared and deposited onto a nanoporous gold (NPG) film (thereafter referred to as NPG-PdSnBi). Consequently, the prepared NPG-PdSnBi catalyst exhibits superior FAOR mass activity (3.54 A·mg_Pd⁻¹), which has surpassed that of many reported Pd-based catalysts and is also competitive with that of some reported Pt-based catalysts. In addition, the prepared NPG-PdSnBi catalyst exhibits superior stability as revealed by the chronoamperometry (CA) test. In situ Fourier transform infrared absorption spectroscopy tests and density functional theory calculations both suggest that the FAOR process catalyzed by the NPG-PdSnBi catalyst corresponds to the direct dehydrogenation path (HCOOH → CO₂ + H₂), thereby inhibiting the poisoning of CO toward the surface of the NPG-PdSnBi catalyst. This work thus paves a pathway for developing high-performance FAOR nanoporous metal catalysts.