Catalytic oxidation of CO over Pt/TiO2 with low Pt loading: The effect of H2O and SO2

New insights into the influence mechanism of H2O and SO2 on Pt–W/Ti catalysts for CO oxidation

“…As shown in Fig. 10(a), the peaks at 2074 cm −1 and 2083 cm −1 belong to CO linearly adsorbed on the Pt 0 site (Pt 0 –CO), the peaks at 2123 cm −1 and 2125 cm −1 belong to CO linearly adsorbed on the Pt 2+ site (Pt 2+ –CO), and the peaks at 2116 cm −1 and 2174 cm −1 are assigned to gaseous CO, 44,60,61 However, no peak (Pt n + –CO) belonging to CO linearly adsorbed on Pt n + (1 < n < 2) sites was found. When H 2 O is introduced into the reaction atmosphere, the CO peak attributed to linear adsorption obviously red-shifted, which may be due to the tendency of oxidized Pt species to obtain electrons, and it may be the reason that there is no infrared peak attributed to ((Pt n + –CO).…”

“…It can be known from the previous research results that there is a fast reaction between *CO and *OH at the metal-support interface to produce the key intermediate HCOO* species. 32,67,68 Feng et al 44 found that H 2 O directly participates in the CO oxidation reaction by dissociation to generate *OH on 0.1Pt/Ti-A, and contributes to most CO 2 production. It is the main path of CO catalytic oxidation under the condition of containing H 2 O. Taira et al 2,69 found that in the coexistence atmosphere of H 2 O and SO 2 , the generated H 2 SO 4 interacted with the support TiO 2 to form a layer of TiOSO 4 species on the surface of the catalyst, which inhibited the interaction between the *OH group on the support and adsorbed CO on Pt site, resulting in the decline of catalytic activity.…”

“…The mass spectrum signal values of C 16 O 2 in the production after the reaction were marked as A and B, respectively. The proportion of C 16 O 18 O in the production CO 2 was calculated using eqn (2): 44 Y = (1 − B / A ) × 100%…”

Effect of TiO2 Calcination Pretreatment on the Performance of Pt/TiO2 Catalyst for CO Oxidation

“…SO 2 and H 2 O can form TiOSO 4 on the TiO 2 surface. However, from the viewpoint of catalytic efficiency, the formation of sulfate does not affect the CO oxidation activity of the Pt/TiO 2 (700 • C) catalyst, probably because SO 2 inhibits the catalytic performance of CO, H 2 O can promote the oxidation of CO and the promotion effect of H 2 O is greater than the inhibition effect of SO 2 [38]. By comparing the proportion of SO 3 2− on the surface of the two catalysts, it is found that the proportion of SO 3 2− on the surface of Pt/TiO 2 (700 • C)-SH is significantly higher than that of Pt/TiO 2 -SH, while SO 3 2− is more unstable and easier to decompose, which will be beneficial to the regeneration of Pt/TiO 2 (700 The dispersion and particle size of precious metals affect catalyst performance.…”

Promotion Effect of the Keggin Structure on the Sulfur and Water Resistance of Pt/CeTi Catalysts for CO Oxidation

“…According to Feng's study [60], H 2 O could enhance the catalytic oxidation of CO, and the promoting effect of H 2 O was greater than the inhibiting effect of SO 2 when H 2 O and SO 2 coexisted in the atmosphere. Similar phenomena were observed over Pt/CeTi and Pt/Keg-CeTi, but it was different for Pt/MoP-CeTi (Figures 1 and 2).…”