Abstract
Carbon monoxide is a poison to the Pt anode in proton exchange membrane fuel cell (PEMFC). Preferential oxidation (PROX) is an effective method to reduce CO in hydrogen-rich gas streams to a tolerant level. In the present work, the effect of adding cobalt to Pt/γ-Al2O3 on the PROX of CO was investigated. Our results showed that the addition of Co to Pt/γ-Al2O3 could not only improve the low-temperature activity but also reduce significantly the loading of Pt in the catalysts. Over the catalyst 3%Co/1%Pt/γ-Al2O3 the conversion of CO was close to 100% at 90 °C and space velocity of 8000 mL g−1 h−1. In addition, the Co-promoted Pt/γ-Al2O3 catalyst showed good resistance to H2O and CO2 and could be operated in a wide range of space velocity. At temperatures above 90 °C, the existence of H2O in the feed increased the conversion and broadened the operating temperature range without worsening the selectivity. When space velocity was changed from 8000 to 80,000 mL g−1 h−1 and temperatures was kept between 120 and 160 °C, the conversion of CO was always over 99% and the decrease in O2 selectivity did not exceed 10%. Furthermore, a strong opposite effect of the ratio of O2 to CO on the conversion of CO and the selectivity of O2 was observed. However, at the O2/CO ratio of 1.0 and temperatures between 120 and 160 °C, a satisfied balance between conversion and selectivity could be obtained.
Published Version
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