Preferential CO oxidation over activated carbon supported catalysts in H2-rich gas streams containing CO2 and H2O

Selective CO oxidation (PROX) was studied at 423 K over 1% Pt–0.25% SnOx and 1% Pt–1% CeOx catalysts supported on un-oxidized and oxidized activated carbon (AC) using feed mixtures simulating the reformate coming from fuel processors. Effects of the addition of 15% CO2 or (15% CO2 + 10% H2O) into feed mixtures containing 1% CO, 1% O2, 60% H2 and He were determined for nine different AC-supported catalysts, and the results were compared with those obtained with pure H2-rich feed. Unlike other PROX catalysts having oxide supports, introduction of CO2 into pure feed drastically increased CO conversion on all nine catalysts supported on oxidized or un-oxidized AC regardless of impregnation strategy.1% Pt–0.25% SnOx supported on HNO3-oxidized AC stands out as a potential candidate for commercial use in PROX since it yields 100% CO conversion under realistic feed conditions. 1% Pt–1% CeOx catalysts prepared by sequential or co-impregnation and supported on air-oxidized AC also give 100% CO conversion in H2-rich feed containing (CO2 + H2O) during extended run times and hence hold promise as PROX catalysts.

Graphical abstractSelective CO oxidation was studied at 423 K over 1%Pt-0.25%SnOx and 1%Pt-1%CeOx catalysts supported on un-oxidized and oxidized activated carbon. Introduction of CO2 and (CO2 + H2O) into feed containing 1%CO, 1%O2, 60%H2 and helium drastically increased CO conversion to 100 per cent. 1%Pt-0.25%SnOx supported on HNO3-oxidized AC and 1%Pt-1%CeOx supported on air-oxidized AC hold promise as potential PROX catalysts. Figure optionsDownload full-size imageDownload as PowerPoint slide