Synthesis of AuCu nanoalloy and investigation on its electrocatalytic proton reduction and CO2 reduction activity
Year: 2025
Type: article
Abstract: Identifying efficient catalysts for the H2 evolution reaction and CO2 reduction, which can operate at low overpotential in a neutral or near-neutral pH aqueous solution, represents a significant challenge. This work reports the synthesis of an AuCu nanoalloy in the form of spherical nanoparticles with an average size of ~16.7±0.3 nm. The morphology, crystal structure, and chemical composition of AuCu nanoparticles were characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution - high angle annular dark field - scanning transmission electron microscopy (HR-HAADF-STEM), and energy dispersive X-ray (EDX) analysis. The use of AuCu nanoparticles as a catalyst for the H2 evolution and CO2 reduction reactions in a 0.1 M KHCO3 (pH 6.8) solution was investigated. It was found that AuCu nanoparticles catalysed the reduction of CO2 to CH4 at a low cathodic potential of -0.2 V vs. Reversible hydrogen electrode (RHE) with a Faradaic efficiency of 7.1%. However, at low cathodic potentials ranging from -0.2 to -0.5 V vs. RHE, H2 evolution was more favourable than CO2 reduction reactions. Conversely, at higher cathodic potentials, e.g. -0.6 V vs. RHE, the reduction of CO2 to CO was more favourable. The AuCu nanoparticles demonstrate superior CO2 reduction selectivity compared to Au and Cu nanoparticle catalysts. A discussion on potential reaction pathways contributing to the CO2 reduction selectivity is also proposed.
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4408686084