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

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.

Ag-AgCl Nanoparticles Fixation on Electrospun PVA Fibres: Technological Concept and Progress

“…Biosynthesis of metallic nanomaterials by bacteria 2 , cyanobacteria 3 , algae 4 , microscopic fungi 5 , live plants and/or waste biomass 6 and different plant extract types has been confirmed, and the individual biomasses contain large numbers of organic compounds composed of positively and negatively charged functional groups. Examples of negatively charged groups include hydroxyl (-OH), amino (-NH 2 ) and carboxyl (-COOH) groups; and metal ions (Ag + or Au + 3 ) can be reduced to zero-valent or different form when the biomass and a metal salt precursor are mixed.…”

Synthesis of Pd/Ru Bimetallic Nanoparticles by Escherichia coli and Potential as a Catalyst for Upgrading 5-Hydroxymethyl Furfural Into Liquid Fuel Precursors

“…Study of bacterially derived Pd/Ru NPs is a new development. Omajali et al (2019) showed the potential of cells of the Gram-positive bacterium Bacillus benzeovorans to make bio-Pd/Ru bimetallic structures using the same approaches as described above for bio-Pd/Au and bio-Pd/Pt. Most of the work on bio-NP catalysts has used Gram-negative bacteria.…”

Synthesis, Properties, and Biological Applications of Metallic Alloy Nanoparticles

“…Nanoparticle-based catalysts are structured with catalytically efficient metals such as Pd, Ni, and Pt. Similar to other alloy nanomaterials, catalysts like Pd–Ru and Pd–Co, made of bimetallic nanomaterials have excellent hybrid catalytic characteristics and exhibit photocatalysis when combined with metals with optical properties like Pt–Au [ 243 , 244 ]. Bimetallic catalysts thus show higher catalytic activity and longer stability than monometallic catalysts.…”

“…For example, between Pd-Ru nanoparticles and Ru nanoparticles produced by Bacillus benzeovorans, Pd-Ru nanoparticles show better catalytic activity than Ru nanoparticles in converting 5-hydroxymethyl furfural (5-HMF) to the fuel precursor 2,5-dimethyl furan (2,5-DMF) [ 243 ]. In methanol and ethanol electrooxidation, Pd-Co nanoparticles supported on graphene show a slight decrease in catalysis but show strong stability, long term use, and magnetic property that allows easy separation from a mixture compared with Pd nanoparticles supported on graphene.…”