Isotope effect of H2/D2 and H2O/D2O for the PROX reaction of CO on the FeOx/Pt/TiO2 catalyst

Abstract

The oxidation reaction of CO with O 2 on the FeOx/Pt/TiO 2 catalyst is markedly enhanced by H 2 and/or H 2 O, but no such enhancement occurs on the Pt/TiO 2 catalyst. Isotope effects were studied by H 2 /D 2 and H 2 O/D 2 O on the FeOx/Pt/TiO 2 catalyst, and almost the same magnitude of isotope effect of ca. 1.4 was observed for the enhancement of the CO conversion by H 2 /D 2 as well as by H 2 O/D 2 O at 60°C. This result suggests that the oxidation of CO with O 2 via such intermediates as formate or bicarbonate in the presence of H 2 O, in which H 2 O or D 2 O acts as a molecular catalyst to promote the oxidation of CO as described below. KEY WORDS: PROX reaction of CO; Isotope effect of H 2 /D 2 and H 2 O/D 2 O; Molecular catalysis of H 2 O; A new PROX catalyst; FeO X loaded Pt/TiO 2 catalyst.

The Mechanism for the Selective Oxidation of CO Enhanced by H2O on a Novel PROC Catalyst

“…We also found that the enhancement of CO conversion by H 2 /D 2 and H 2 O/D 2 O takes a common hydrogen isotope effect of ca. 1.4 at 60°C [5]. These results strongly suggest that H 2 O molecule contributes to the oxidation reaction of CO and hydrogen is involved at the rate determining step on the FeO x /Pt/TiO 2 catalyst.…”

Promoting mechanism of potassium in preferential CO oxidation on Pt/Al2O3

“…Furthermore, the TOF in PROX was much higher than that in CO+O 2 on K-Pt/Al 2 O 3 (10). One of the promoting mechanisms of H 2 to CO oxidation may be due to the water gas shift reaction originated from H 2 oxidation to H 2 O on the basis of the previous reports [9,[23][24][25][26][27]. Therefore, the activity of the water gas shift reaction was also measured and the TOF obtained is listed in Table 1.…”

“…There have been a lot of reports on supported noble metal catalysts such as Pt , Pd [15,34], Ru [15,35] and Rh [36][37][38][39] for the preferential CO oxidation in H 2 -rich gas. In particular, the effect of various additives has been investigated [6,11,18,19,24,25,27]. In addition, Au [40][41][42][43][44][45][46] and Cu [47][48][49][50] catalysts also exhibited high performance, and these behaviors can be generally explained by the weaker interaction with CO compared to noble metal catalysts.…”

AuPt Alloy Nanoparticles for CO‐Tolerant Hydrogen Activation: Architectural Effects in Au‐Pt Bimetallic Nanocatalysts

“…[23][24][25][26] A PROX catalyst will selectively oxidize CO to CO 2 before oxidizing hydrogen in a CO/O 2 /H 2 feed. CO-tolerance can be achieved by either oxidation of the CO [27] or through the weakening of CO adsorption.…”