CeO2 nanorods supported M–Co bimetallic oxides (M = Fe, Ni, Cu) for catalytic CO and C3H8 oxidation

Supported bimetallic catalysts with rational compositions and structural design have attracted great interest, due to the tunable structural orientation (alloy or intermetallic compound and core-shell structure etc.), synergetic effects, and combined properties related to the presence of two individual metals. In this study, 10 wt% Fe-Co, Ni-Co and Cu-Co bimetallic oxides with 1:2 atomic ratio (FeCo2Ox, NiCo2Ox and CuCo2Ox) were deposited onto CeO2 nanorods (CeO2NR) via a hydrothermal-assisted precipitation-deposition method. The bimetallic synergism effects, surface structure configuration and the metal (oxide)-support interactions were investigated. The catalysts were characterized by means of powder XRD, TEM, EDX, Raman spectroscopy, XPS, BET surface area, H2-TPR, O2 pulse chemisorption and O2-TPD. All the CeO2NR supported bimetallic catalysts show considerable low-temperature CO oxidation performance. And the catalytic activity toward CO oxidation follows the order: 10 wt% CuCo2Ox/CeO2NR (T50 = 95 °C and T90 = 148 °C) > 10 wt% FeCo2Ox/CeO2NR (T50 = 129 °C and T90 = 193 °C) > 10 wt% NiCo2Ox/CeO2NR (T50 = 147 °C and T90 = 196 °C). As for the catalytic oxidation of C3H8, all the designed catalysts show similar low-temperature performance, but the 10 wt% NiCo2Ox/CeO2NR catalyst exhibits the maximum C3H8 conversion above 330 °C. In addition, we also demonstrate the important role of oxygen storage capacity (OSC) of CeO2NR support and the impact of different oxygen species (physi-/chemisorbed oxygen, and bulk lattice oxygen) on the oxidation of CO and light hydrocarbons.