Advanced PtCo Catalysts Based on Platinum Acetate Blue for the Preferential CO Oxidation in H2-Rich Mixture

Abstract

Preferential oxidation of carbon monoxide (CO-PROX) in H2-rich mixture is an effective way of hydrogen purification for fuel cells. High-performance PtCo/ZSM-5 catalysts with reduced Pt loading for this process were prepared using polynuclear platinum acetate complex known as platinum acetate blue (PAB) of the empirical formula Pt(CH3COO)2.5 as a novel precursor. The impregnation of HZSM-5 (Si/Al = 15 and 28) with PAB and its decomposition at 200 °C resulted in the stabilization of highly dispersed Pt0 and PtOx species on the zeolite surface. The catalytic properties were improved by the addition of Co(CH3COO)2 followed by calcination at 450 °C. Produced materials were studied by SEM, TEM, EDX, XPS, and DRIFTS methods and tested in a CO-PROX reaction. The relationship between the synthesis conditions, structure, and catalytic behavior of composites is discussed in this paper. The synergistic effect of Pt and Co was observed when they both were located together in zeolite channels. The Pt-Co interaction provides new active catalytic sites and prevents platinum aggregation during the process. Due to this, the 100% CO conversion in the wide temperature range from 50 to 130 °C is achieved for PtCo/ZSM-5 catalysts (Si/Al = 15), which is the best result compared to low-loaded Pt catalysts prepared with traditional precursors.