Hydrogen and High-Value-Added Chemicals from Glycerol Electroreforming Using a Highly Efficient and Selective Ligand-Stabilized PdCu Catalyst

Abstract

PdCu alloy nanoparticles stabilized by a secondary diamine ligand (L) bearing C16-alkyl chains at the nitrogen atoms were successfully synthesized. The PdCuL supported on Vulcan XC-72 (C^v) with a very low metal loading (1 wt %) was applied in alkaline glycerol electroreforming experiments for both hydrogen generation and chemicals. The PdCuL/C^v electrocatalyst exhibited excellent activity as an anode material for glycerol oxidation with a specific activity of 6 A mg_Pd^–1 at 1 V and a notable selectivity (up to 95%) for high-value C3 oxidation products (glycerate and tartronate). Sterically demanding L allows the obtaining of small and stable size-controlled nanoparticles (d_m 1.9 ± 0.7 nm) observed through high-resolution transmission electron microscopy (TEM) analysis before and after catalysis testing. The catalyst was also thoroughly investigated by X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) techniques. The Pd–Cu synergistic effect on alcohol oxidation catalysis was verified through electrochemical experiments, which highlight the superior catalytic activity of PdCuL/C^v (up to 3 times) compared to a monometallic catalyst.