Dispersed single-atom Co and Pd nanoparticles forming a PdCo bimetallic catalyst for CO oxidation

Abstract

PdCo bimetallic catalysts were synthesized using oleyamine and oleaic acid as capping agents to effectively disperse the metals over activated carbon via incipient impregnation. The synthesis, in conjunction with the carbon support, resulted in single-atom dispersion of Co over the carbon with the formation of Pd nanoparticles. Thermal activation of the catalysts, under a reducing atmosphere, allowed sufficient Pd and Co mobility leading to the formation of a PdCo alloy, according to STEM, in situ XRD and XANES analysis. Furthermore, molar percentages between 0.2 to 0.3 in Co were effective in producing Pd nanoparticles that are partially decorated with Co to produce a highly active catalyst for CO oxidation. The optimized catalyst formulation and synthesis method provide active sites for CO absorption onto Pd while maintaining active sites, in close proximity, for O2 activation via Co. The resulting catalyst showed a marked reduction in CO light-off temperatures compared to the monometallic formulations.