Promotion Effect of Cu for CO Oxidation on Ceria Supported Pd_xCu_y Bimetallic Catalysts

Abstract

The surface composition and structure of bimetallic catalysts are important for the catalytic performance. In this work, Pd x Cu y /CeO 2 catalysts with various Pd/Cu ratios were prepared and characterized by surface-sensitive techniques combined with ex-situ pretreatment. CO oxidation was used to correlate the surface composition with the catalytic performance. Compared with the monometallic Pd/ CeO 2 and Cu/CeO 2 , the Pd x Cu y /CeO 2 bimetallic catalysts with a small amount of Cu show much higher CO oxidation activities. High-sensitivity low-energy ion scattering spectroscopy (HS-LEIS) combinded with X-ray photoelelctron spectroscopy (XPS) and temperature-programmed reduction (H 2 -TPR) results indicate that adding a small amount of Cu can efficiently promote the surface dispersion of Pd and affect the redox properties, whereas the CO oxidation activity is significantly suppresssed after adding a larger amount of Cu, which may be mainly induced by the preference for surface segregation of Cu that blocks the active site of Pd.

The Journal of Physical Chemistry C Virtual Special Issue on “Energy and Catalysis in China”

“…(1) Energy catalysis: conversion of syngas to higher alcohols on CoMn-modified Cu-based mixed oxides, direct methane conversion to methanol on PdAu nanowires, hydrogenation of CO 2 to ethanol on Na-promoted Rh embedded in S-1 zeolites, oxidative coupling of methane on A +1 Nb 5+ O 3 (A = Li, Na, K) perovskites, and synthesis of jet fuel from glycerol and tert -butyl alcohol on organic solid acid catalysts . (2) Environmental catalysis: catalytic elimination of soot and NO x on Mn-based perovskites, catalytic dehydrochlorination of dichloroethane on porous carbon, oxidation of propane and CO on reducible oxide-supported Pt or PtCu nanocatalysts, , complete oxidation of benzene on Pt SACs, preferential oxidation of CO on Cu x Ce 1– x O 2 nanorods, CO oxidation on Pd/ZnO catalysts or Au–Fe 2 O 3 interfaces, and selective catalytic reduction of nitrogen oxide with methane on Co-exchanged SSZ-13 zeolite catalysts . (3) Synthesis of fine chemicals: selective reduction of nitrobenzene on iron and nitrogen cofunctionalized carbon materials or PtPdCu/Al 2 O 3 , hydrogenation of quinoline and benzoic acid on RhPt/MCM-41, hydroformylation of diisobutene on CoFe alloy catalysts, and selective hydrogenation of cinnamaldehyde to cinnamyl alcohol on Pt@Fe-CeO 2 catalysts or Pt/TiO 2 .…”