Effect of CO atmosphere on morphology and electrochemically active surface area in the synthesis of Pt/C and PtAg/C electrocatalysts

Resumo

An effect of CO atmosphere on the microstructure of Pt/C, PtAg/C, and Ag@Pt/C electrocatalysts formed in the synthesis and on the electrochemically active surface area (ECAS) has been studied. Synthesis is carried out via the joint or sequential chemical reduction of silver and platinum precursors in a suspension of Vulcan XC-72 disperse carbon carrier. Adsorption of CO molecules on a surface of platinum and Pt-Ag is shown to hamper their growth and aggregation, leading to a considerable increase in ECAS of platinum, as well as Pt/C and PtAg/C materials to be synthesized. The impact of CO on the morphological characteristics of the Ag@Pt/C materials containing a significant proportion of bimetallic nanoparticles (NPs) with an Ag-core/Pt-shell structure is less because of the weak adsorption of CO on the silver surface. ECAS values of platinum in the materials synthesized in the CO atmosphere were 152, 88, and 75 m2/g for Pt/C, PtAg/C, and Ag@Pt/C materials, respectively.