Novel catalytically active Pd/Ru bimetallic nanoparticles synthesized by Bacillus benzeovorans

Sci Rep. 2019 Mar 18;9(1):4715. doi: 10.1038/s41598-019-40312-3.

Abstract

Bacillus benzeovorans assisted and supported growth of ruthenium (bio-Ru) and palladium/ruthenium (bio-Pd@Ru) core@shell nanoparticles (NPs) as bio-derived catalysts. Characterization of the bio-NPs using various electron microscopy techniques and high-angle annular dark field (HAADF) analysis confirmed two NP populations (1-2 nm and 5-8 nm), with core@shells in the latter. The Pd/Ru NP lattice fringes, 0.231 nm, corresponded to the (110) plane of RuO2. While surface characterization using X-ray photoelectron spectroscopy (XPS) showed the presence of Pd(0), Pd(II), Ru(III) and Ru(VI), X-ray absorption (XAS) studies of the bulk material confirmed the Pd speciation (Pd(0) and Pd(II)- corresponding to PdO), and identified Ru as Ru(III) and Ru(IV). The absence of Ru-Ru or Ru-Pd peaks indicated Ru only exists in oxide forms (RuO2 and RuOH), which are surface-localized. X ray diffraction (XRD) patterns did not identify Pd-Ru alloying. Preliminary catalytic studies explored the conversion of 5-hydroxymethyl furfural (5-HMF) to the fuel precursor 2,5-dimethyl furan (2,5-DMF). Both high-loading (9.7 wt.% Pd, 6 wt.% Ru) and low-loading (2.4 wt.% Pd, 2 wt.% Ru) bio-derived catalysts demonstrated high conversion efficiencies (~95%) and selectivity of ~63% (~20% better than bio-Ru NPs) and 58%, respectively. These materials show promising future scope as efficient low-cost biofuel catalysts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus / chemistry
  • Bacillus / metabolism*
  • Biofuels*
  • Catalysis
  • Furaldehyde / analogs & derivatives
  • Furaldehyde / chemistry
  • Furans / chemical synthesis*
  • Industrial Microbiology / methods*
  • Metal Nanoparticles / chemistry*
  • Metal Nanoparticles / ultrastructure
  • Microscopy, Electron, Transmission
  • Oxidation-Reduction
  • Palladium / chemistry
  • Photoelectron Spectroscopy
  • Recycling
  • Ruthenium / chemistry

Substances

  • Biofuels
  • Furans
  • Palladium
  • 5-hydroxymethylfurfural
  • Ruthenium
  • Furaldehyde
  • 2,5-dimethylfuran