Experimental Evaluation on the Catalytic Activity of a Novel CeZrK/rGO Nanocomposite for Soot Oxidation in Catalyzed Diesel Particulate Filter

Abstract

A nanostructured solid solution catalyst CeZrK/rGO for soot oxidation in catalyzed diesel particulate filter was synthesized using the dipping method. The reduced graphene oxide (rGO) was used as the catalyst carrier, and CeO2, ZrO2, and K2O were mixed with the molar ratio of 5:1:1, 5:2:2 and 5:3:3, which were referred to as Ce5Zr1K1/rGO, Ce5Zr2K2/rGO, and Ce5Zr3K3/rGO, respectively. The structure, morphology and catalytic activity of the CeZrK/rGO nanocomposites were thoroughly investigated and the results show that the CeZrK/rGO nanocomposites have nanoscale pore structure (36.1–36.9 nm), high-dispersion quality, large specific surface area (117.2–152.4 m2/g), small crystallite size (6.7–8.3 nm), abundant oxygen vacancies and superior redox capacity. The 50% soot conversion temperatures of Ce5Zr1K1/rGO, Ce5Zr2K2/rGO, and Ce5Zr3K3/rGO under tight contact condition were decreased to 352 °C, 339 °C and 358 °C respectively. The high catalytic activity of CeZrK/rGO nanocomposites can be ascribed to the following factors: the doping of Zr and K ions causes the nanocrystalline phase formation in CeZrK solid solutions, reduces the crystallite size, generates abundant oxygen vacancies and improves redox capacity; the rGO as a carrier provides a large specific surface area, thereby improving the contact between soot and catalyst.

CO2 Reforming of Ethanol over Ni/Al2O3-(Zr–Yb)O2 Catalysts: The Effect of Zr:Al Ratio on Nickel Activity and Carbon Formation

“…The Zr 3d photoelectron peaks (Figure S6) were observed for the two samples: for Ni/35AZ - at 182.7 and 185.16 eV, for Ni/65AZat 181.1 and 183.6 eV. These values correspond to Zr 3d 5/2 and Zr 3d 3/2 , respectively, which are assigned to the +4 oxidation state of the zirconium. − The O 1s photoelectron peaks of Ni/35AZ and Ni/65AZ samples were deconvoluted in four peaks at 528, 530, 531, and 532.5 eV (Figure ), which were attributed to lattice oxygen (O L ) < 530 eV, oxygen vacancies (O V ) ∼531 eV, and chemically adsorbed oxygen species (O C ) 532.5 eV, respectively. − The oxygen vacancy ratios were calculated using the formula O V /(O V + O L ) (Table ). For the reduced Ni/35AZ and Ni/65AZ samples, the oxygen vacancy ratios were found to be 0.660 and 0.642, respectively.…”

Optimization of Spray-Drying Process with Response Surface Methodology (RSM) for Preparing High Quality Graphene Oxide Slurry

“…Since x1 is the most influential variable, we can determine that among three factors, the nozzle airflow rate (X 1 ) had major effects on all responses. 2 Atomization pressure, 3 Liquid feed rates. ns -Not significant, * significant at p < 0.05, ** significant at p < 0.01.…”

“…Graphene oxide (GO) is an important precursor for the preparation of graphene by the redox method, and it is also called functionalized graphene due to the existence of hydroxyl and carboxyl groups covalently bonding to the planar carbon network [1].These abundant oxygen functional groups are not only beneficial to subsequent modification and dispersion processes but also serve as new active sites, endowing GO broad application prospects in energy storage and conversion, composites, adsorption, etc. [2][3][4][5][6][7][8]. In order to realize wide applications of GO, a high-concentration well-dispersed GO dispersion is often required for forming macroscopic assembly.…”

The low-temperature synthesis of cation-ordered Ce–Zr-based oxide via an intermediate phase between Ce and Fe

“…Another approach to improving the OSC of CZ is doping with various elements, such as rare earths, 12,13 alkali metals, and alkaline earths. 14,15 Recently, solid solutions of transition metals (TM) and CZ have shown an improved OSC at low temperatures of 600 °C and even lower. 16–19 Guangfeng et al reported that Pd-only TWCs with TM-doped CZ (where TM = Cr, Mn, Fe, Co, Ni) have improved catalytic performance with respect to the decrease of the light-off and full-conversion temperature.…”