Dry plasma reduction to prepare a high performance Pd/C catalyst at atmospheric pressure for CO oxidation

Abstract

A high performance Pd/C catalyst (Pd/C-PC) was successfully prepared by simple incipient wetness impregnation followed by the process of dry plasma reduction and calcination. Oxygen-containing group surface-fuctionalized activated carbon was used to absorb the palladium precursor PdCl₄²⁻, and small sized (1.92 ± 0.75 nm) Pd nanoparticles were formed in Pd/C-PC, which were smaller than those prepared by low pressure cold plasma (4.0–4.5 nm). The results of XRD, XPS, TPR and TEM showed that dry plasma with calcination could completely remove the residual Cl⁻ ions and obtain predominantly metallic Pd nanoparticles without aggregation. The dry plasma prepared Pd/C-PC catalyst gave excellent catalytic activity for CO oxidation, and the TOF value for 5 wt% Pd/C-PC was about 6.1 times as that for 6 wt% Pd/graphene prepared by the conventional impregnation and hydrogen reduction method. The high performance was attributed to the smaller size and predominantly metallic Pd nanoparticles.