Design of bimetallic Au/Cu nanoparticles in ionic liquids: Synthesis and catalytic properties in 5‐(hydroxymethyl)furfural oxidation

Abstract

In alloyed nanoparticles, synergistic electronic and/or geometric effects may enhance the catalytic properties compared to their monometallic counterparts. Herein, we address the synthesis of bimetallic Au/Cu nanoparticles with different compositions by wet chemical reduction in ionic liquids. The nanoparticles were successively supported on carbon. The ionic liquid could be recycled after synthesis. Annealing of the carbon‐supported NPs at 400 °C led to NPs of the ordered intermetallic L10 AuCu phase. The nanoparticle‐derived catalysts were characterized by X‐ray diffraction analysis, transmission electron microscopy, X‐ray photoelectron spectroscopy and optical emission spectroscopy with inductively coupled plasma. Oxidation of biomass‐derived furans is a prominent process for biomass transformation into value‐added chemicals. Herein, the oxidation of 5‐hydroxymethyl‐2‐furfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) was chosen as a model reaction to evaluate the effect of Cu addition and intermetallic structure on the catalytic performance. Particularly Au/Cu nanoparticles with an Au/Cu ratio of 3 : 1 showed very high conversion to FDCA.

Enzyme-Assisted Metabolically Coated Bimetallic Thalassiosira pseudonana Nanosilica as a Surface-Enhanced Raman Scattering Substrate for Specific Screening of Prostate Cancer Individuals

“…All survey spectra display the standard frustule characteristic signals for Si (2p, 2s, 102 eV) and O 1s (532 eV) corresponding to SiO 2 , the backbone diatom frustules . The Au/Cu X -coated frustules displayed additional peaks of Au (84–88 eV) and Cu X (930–96 eV), reflecting the presence of Au/Cu X on the diatom frustule surface . As expected, upon immobilization of SoX on Au/Cu X frustules, the intensity decreases of Au/Cu X and Si 2p peaks, along with the intensity increase of N 1s (400 eV) and C 1s (285 eV) binding energy peaks, provided conclusive proof of SoX grafting.…”

“…32 The Au/Cu X -coated frustules displayed additional peaks of Au (84−88 eV) and Cu X (930− 96 eV), reflecting the presence of Au/Cu X on the diatom frustule surface. 19 As expected, upon immobilization of SoX on Au/Cu X frustules, the intensity decreases of Au/Cu X and Si 2p peaks, along with the intensity increase of N 1s (400 eV) and C 1s (285 eV) binding energy peaks, provided conclusive proof of SoX grafting. It should be noted that no observable signal for N 1s was found on pure diatom frustules, indicating that the N 1s peak is from the SoX enzyme.…”

“…The Au/Cu X -DF peaks seem slightly shifted to higher diffraction angles than the Au-DF. The shift of diffraction peaks to the higher angles is a characteristic of the decrease of the lattice parameters due to the incorporation of Cu atoms into the Au-coated DF 19 (Figure S3a).…”

“…Bimetallic NPs, compared to counterparts (single metals), offer great promise for sensing and catalysis. − Copper (Cu) as an additive for improving the catalytic activity of noble metals improves the catalytic performance and the catalyst cost . Adding Cu to Au NPs significantly enhances the catalytic reactions; , however, preparing bimetallic nanostructures typically requires high temperature, prolonged reaction time, and harmful organic reagents. − Ecofriendly synthesis of bimetallic nanosystems having catalytic and optoelectronic properties with controllable morphologies for SERS detection of biomarkers is challenging but significant for diagnosis advancement. Herein, for the first time, we fabricate a BioPNS SERS tag containing bimetallic NPs coated on diatom frustules using a live diatom T.…”

Continuous flow oxidation of HMF using a supported AuPd-alloy

“…1,13,17,18 Despite the higher cost associated with noble metal-based catalysts, their superior activity and stability, coupled with the utilization of air as a green and safe oxidant make them compelling candidates. 6,[19][20][21] A list of noble metals, including Au, 6,7,19,22,23 Pt, 20,[24][25][26] Pd, 27,28 Ru, [29][30][31] and Ag, 32,33 and various bimetallic combinations 8,21,[34][35][36][37][38] have been reported for the oxidation of HMF. Their successful deployment not only attests to their catalytic efficiency but also aligns with a closed-cycle approach, wherein the catalysts exhibit reusability and end-of-life noble metals can be recycled for subsequent catalyst preparation.…”