Synthesis, structure and three way catalytic activity of Ce1−xPtx/2Rhx/2O2−δ (x = 0.01 and 0.02) nano-crystallites: Synergistic effect in bimetal ionic catalysts

Bimetal ionic Ce1−xPtx/2Rhx/2O2−δ (x = 0.01 and 0.02) catalysts have been synthesized by a single step solution combustion method. CO and C2H4 oxidation and NO reduction activities of the bimetal ionic catalysts are compared with mono-metal ionic Ce1−xPtxO2−δ (x = 0.01 and 0.02) and Ce1−xRhxO2−δ (x = 0.01 and 0.02) catalysts. X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) studies show incorporation of Pt2+ and Rh3+ ions in CeO2 lattice. Low temperature hydrogen uptake at 0 °C and below over bimetal ionic catalyst shows enhanced redox property over the corresponding mono-metal ionic analogues. The TOF for CO oxidation over Ce0.99Pt0.005Rh0.005O2−δ is 0.035 s−1 at 120 °C, compared to 0.003 s−1 over Ce0.99Pt0.01O2−δ and 0.035 s−1 over Ce0.99Rh0.01O2−δ at 135 °C. Enhanced catalytic activity of Ce1−xPtx/2Rhx/2O2−δ (x = 0.01) bimetal ionic catalysts compared to mono-metal ionic catalysts, Ce1−xPtxO2−δ and Ce1−xRhxO2−δ, is attributed to synergism brought about by the easy reduction of Rh3+ ion by Pt2+ ion.

Graphical abstractBimetal ionic Ce1−xPtx/2Rhx/2O2−δ (x = 0.01 and 0.02) catalyst with Pt in 2+ and Rh in 3+ states is synthesized by a single step solution combustion method. The bimetal ionic catalyst induces reduction of Rh3+ at a lower temperature in presence of Pt2+ ion compared to the corresponding mono-metal ionic catalysts, Ce1−xPtxO2−δ and Ce1−xRhxO2−δ, showing enhanced catalytic activity as well as synergistic effect.Figure optionsDownload full-size imageDownload as PowerPoint slide