Anisotropic growth of PtFe nanoclusters induced by lattice-mismatch: Efficient catalysts for oxidation of biopolyols to carboxylic acid derivatives

Abstract

By exploiting the large difference in lattice constants between Pt and Fe metals, anisotropic growth of bimetallic PtFe clusters with high index numbers have been prepared to investigate their catalytic performance in oxidation of biopolyols. Surface characterization using transmission electron microscopy shows that etching effects caused by Fe 3+ and anisotropic growth induced by lattice mismatch contributed to the final nanocrystal geometry. The bimetallic PtFe heterocluster is shown to exhibit an unprecedented six-fold enhanced catalytic activity and threefold higher selectivity compared to monometallic Pt and Fe catalysts, in oxidation of biomass-derived polyols to dicarboxylic acids. A detailed study on structure-dependent kinetics of oxidation of glycerol, based on concentration-time profiles on Pt and PtFe catalysts, reveals that the presence of Fe in Pt catalysts significantly enhances the rate of oxidation and decreases the activation barriers for primary and secondary oxidation steps leading to enhanced catalytic activity and selectivity. The lattice mismatch methodology employed in this work provides a unique tool for designing high index catalytically active materials for various other industrial applications.

Liquid-Phase Oxidation of Ethylene Glycol on Pt and Pt–Fe Catalysts for the Production of Glycolic Acid: Remarkable Bimetallic Effect and Reaction Mechanism

“…1% Pt/CeO 2 and 1% Pt−Fe/CeO 2 catalysts were prepared following the method reported previously. 17 N-dimethylformamide (DMF) (HPLC grade, >99.9%), cerium oxide nanopowder (particle size <50 nm, surface area = 30 m 2 /g by BET), and Pt(acac) 2 and Fe(acac) 3 (acac = acetylacetonate) were all purchased from Sigma−Aldrich and used without further purification. The molar ratio of Pt and Fe precursors is (1:1).…”

“…The sizes of Pt and Pt−Fe nanoparticles are 11.8 ± 3.8 nm and 17.3 ± 4.9 nm, respectively, as inferred from transmission electron microscopy (TEM) micrographs. 17 Powder X-ray diffraction (XRD) pattern for the bimetallic Pt−Fe catalyst was obtained on a Bruker D8 powder diffractometer with a copper target (Cu Kα radiation) operating at 40 kV and a current of 40 mA. X-ray absorption spectroscopy (XAS) was performed at the SPring-8/BL36XU facility in Japan.…”

Nanostructured Metal Catalysts for Selective Hydrogenation and Oxidation of Cellulosic Biomass to Chemicals

“…Therefore, rational design of nanostructured metal catalysts for selective synthesis of tartronic acid still remains a grand challenge. We recently reported Fe modified Pt nanocatalysts using lattice mismatched technique . The large lattice difference between Pt (a fcc metal, lattice constant: 0.39 nm) and Fe ( bcc , 0.29 nm) intrinsically drives anisotropic growth of disordered PtFe nanoclusters on CeO 2 support.…”

“… HR‐TEM images of (a) Pt, (b) disordered PtFe, (c) ordered PtFe catalysts with insets at lower magnification (White bars indicate 5 nm). (d) Activity and yield of tartronic acid (70 °C, 0.1 MPa O 2 pressure) request permission from ref…”

Selective glycerol oxidation over ordered mesoporous copper aluminum oxide catalysts

“…11 Also, the catalytic formation of formic acid from biomass recently has attracted attention for energy conversion related applications. [12][13][14] Active catalysts for this reaction most often are composed of supported noble metal nanoparticles, such as Au, [15][16][17][18][19][20][21] Pd, [15][16][17]22,23 Pt, [15][16][17][24][25][26][27][28][29] Ag, 30 and alloys 17,[31][32][33] thereof, which were frequently demonstrated to catalyze selective glycerol oxidation in neutral and basic media. Furthermore, noble metal/Cu alloys are also reported as active catalysts for the selective oxidation of glycerol.…”