Pt–Ni/γ-Al2O3 catalyst for the preferential CO oxidation in the hydrogen stream

Abstract

The preferential CO oxidation (PROX) in the presence of excess hydrogen was studied over Pt-Ni/c-Al 2 O 3 . CO chemisorption, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy and temperature-programmed reduction were conducted to characterize active catalysts. The co-impregnated Pt-Ni/c-Al 2 O 3 was superior to Pt/Ni/c-Al 2 O 3 and Ni/Pt/cAl 2 O 3 prepared by a sequential impregnation of each component on alumina support. The PROX activity was affected by the reductive pretreatment condition. The pre-reduction was essential for the low-temperature PROX activity. As the reduction temperature increased above 423 K, the CO 2 selectivity decreased and the atomic percent of Ni in the bimetallic phase of Pt-Ni increased. This catalyst exhibited the high CO conversion even in the presence of 2% H 2 O and 20% CO 2 over a wide reaction temperature. The bimetallic phase of Pt-Ni seems to give rise to high catalytic activity for the PROX in H 2 -rich stream.

Pt-Co and Pt-Ni Catalysts of Low Metal Content for H2 Production by Reforming of Oxygenated Hydrocarbons and Comparison with Reported Pt-Based Catalysts

“…e order of CO chemisorption capacity of the catalysts is Pt > PtCo > PtNi. ese results coincide with the reports of Ko et al [21] which indicate that the addition of Ni to Pt/Al 2 O 3 catalysts decreases the number of accessible sites for CO adsorption, though it improves the activity for preferential CO oxidation in the presence of H 2 . e CO chemisorption capacity of the NiCo-UMC catalysts is similar to that of the monometallic Pt catalysts, but the metal concentration of the latter is six times greater.…”

The preferential oxidation of CO in hydrogen rich streams over platinum doped nickel oxide catalysts

“…There is a pronounced influence on the NiO reduction temperature for the Pt-Ni-Al sample following the addition of Pt. The reduction temperature shifts to a lower temperature, attributed mainly to the change in mechanism of the NiO reduction [21,29,30].…”

“…The increase in the broadness and peak shoulder at 670 °C could be an indication that NiO particles are loosely bound to the support, and these particles saturate the surface of the support forming bulk NiO [28]. For the mono-metallic Pt-Al catalyst, a broad reduction peak is observed at around 350 °C, which can be assigned to the reduction of platinum oxide to its metallic form [29]. There is a pronounced influence on the NiO reduction temperature for the Pt-Ni-Al sample following the addition of Pt.…”

Metallic osmium and ruthenium nanoparticles for CO oxidation

“…However, the activity depends critically on the particle size and is hence susceptible to sintering [4]. Other materials investigated include Ru [5], RuO 2 [6], CuO/CeO 2 [7], Pd [8], Pt [9,10], and alloys such as Al 1 Mn 6.7 Co, and Ag 3.3 Mn 34.1 Co 1.7 Ni [11]. Recent research has shown that hydrous ruthenium oxide is a very active catalyst for the oxidation of CO.…”