Enhanced catalytic efficiency of bimetallic Pt-Pd on PAMPs-modified graphene oxide for formic acid oxidation

Abstract

A catalyst composed of 2-acrylamido-2-methyl-1-propane sulfonic acid (PAMPs) modified graphene oxide (GO) as the supporting material (PAMPs/GO) and electrodeposited monometallic and bimetallic catalysts (Pt and/or Pd) as the active catalytic component was fabricated to enhance the formic acid oxidation. The morphology of the prepared catalysts was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while the chemical compositions were identified by energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Functional groups of the supporting materials and catalysts were identified by Fourier transform infrared (FT-IR) spectroscopy. The electrochemical measurements of the synthesized catalysts were evaluated by cyclic voltammetry (CV) and chronoamperometry (CA), respectively. The kinetics of formic acid oxidation on the synthesized catalysts were determined by Tafel extrapolation of linear sweep voltammograms. The CO tolerance of the electrocatalyst was examined by CO stripping measurements. The results showed that the catalysts with PAMPs exhibited much higher electrocatalytic activity and longer-term stability for formic oxidation than the catalyst without PAMPS. In addition, the 3Pt3Pd/10%PAMPs/GO catalyst showed the greatest catalytic activity, stability, and fastest charge transfer kinetics when compared to other bimetallic catalysts and monometallic catalysts. In conclusion, modifying the GO surface with PAMPs can improve the efficiency of the electrocatalyst activity of Pt/Pd catalysts. The 3Pt3Pd/10%PAMPs/GO catalyst is a promising electrocatalyst for the enhancement of formic acid oxidation.