Assembling Palladium and Cuprous Oxide Nanoclusters into Single Quantum Dots for the Electrocatalytic Oxidation of Formaldehyde, Ethanol, and Glucose

Abstract

To effectively manipulate the electronic structure of the catalysts, we present here a simple bottom-up synthesis protocol for agglomerating palladium and cuprous oxide ultrasmall nanoclusters into single nanoparticles, forming so-called quantum dot assemblies (QDAs). Our synthesis is based on the galvanic displacement of copper with palladium cations under O2-free conditions, rendering the simultaneous and unique crystal growth of ∼3 nm Cu2O and Pd clusters. Such assemblies, comprising ultrasmall nanoconstitutes, offer much more phase boundaries, where the interfacial electronic effect becomes prominent in catalysis. This is demonstrated in the electrocatalytic oxidation of formaldehyde, ethanol, and glucose. In all three cases, the QDA catalyst, despite its similar Pd loading, outperforms the monometallic palladium catalyst. Indeed, complementing the experimental results with density functional theory calculations, we could confirm the sharply increased charge density at the Pd–Cu heterojunction and the decreased energy barrier of the formaldehyde oxidation on the QDA catalyst. Finally, we applied these catalysts in electroless copper deposition – an industrially relevant process for manufacturing printed circuit boards. The QDA catalysts gave uniform and robust copper wires at a rate that was three times faster than that of the monometallic Pd catalyst, showing their potential for real-life applications.

Bimetallic nickel/manganese phosphate–carbon nanofiber electrocatalyst for the oxidation of formaldehyde in alkaline medium

“…Fe/FeZM-CPE, 46 Ni–Pd/SiMCP, 47 Pd/PPy composite, 48 and CuO/Cu/TiO 2 nanotube arrays, 49 offered superior electroactivity for the formaldehyde oxidation than mono metallic catalysts. Also, bimetallic Pd/Cu 2 O nanoclusters, 50 and (NiWO 4 ) nanoparticles, 51 showed better electroactivity for formaldehyde oxidation than individual metallic materials. These results were attributed to the synergistic effect between transition metals in the electrocatalysts.…”

Alternative Local Melting‐Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

“…[28,29] To overcome these problems, many works in the literature report the use of copperbased materials, mostly in metallic form. [30][31][32][33][34][35][36] The use of copper particles to increase the surface area, which is the most important factor for high catalytic performance, has been limited due to their susceptibility to oxidation under atmospheric conditions. There have been numerous efforts to develop methods to increase the stability of Cu particles by modifying their sensitivity in contact with chemical substances, including the use of alternative Cu-based particles with more complex structures based on copper oxides.…”