Low Temperature PROX Reaction of CO Catalyzed by Dual Functional Catalysis of the Pt Supported on CNT, CNF, Graphite, and Amorphous-C with Ni−MgO, Fe, and Fe-Al2O3: Oxidation of CO via HCOO Intermediate

Abstract

Preferential oxidation (PROX) reaction of CO in H2 proceeded rapidly on Pt supported on carbon nanotube (CNT) at room temperature, whereas the oxidation of CO was very slow in the absence of H2. On the other hand, no low temperature PROX reaction proceeded on Pt supported on the CNT purified Ni−MgO (CNT-p). Similarly, Pt supported on carbon nanofiber (Pt/CNF) was extremely active for the PROX reaction of CO at room temperature, but the activity of Pt supported on purified CNF (CNF-p) was very low. Pt particles are on the wall of CNT and CNF, whereas Ni−MgO and Fe are at the end of CNT and CNF. When Ni−MgO or Fe−Al2O3 was doped to inactive Pt/CNT-p, Pt/CNF-p, Pt/graphite, and Pt/amorphous-C (a-C), the activity for the oxidation of CO in H2 was markedly improved but no effect on the oxidation of CO in the absence of H2. The kinetic feature of the oxidation of CO on Pt/CNT in the presence of H2 or H2O was very similar to that on the FeOx/Pt/TiO2, where the oxidation of CO in the presence of H2/D2 had an isot...