Active catalysts of electrochemically prepared gold nanoparticles for the decomposition of aldehyde in alcohol solutions

In this work, sonoelectrochemically synthesized gold nanoparticles with diameters of ca. 20 nm were prepared from gold sheets in NaCl aqueous solutions without the addition of any stabilizer. First, an Au substrate was cycled in a deoxygenated aqueous solution containing 0.1 M NaCl from -0.28 to +1.22 V vs. Ag/AgCl at 500 mV/s for 100 scans. The durations at the cathodic and anodic vertexes are 10 and 5 s, respectively. After this process, Au-containing complexes were left in the solution. Then the Au working electrode was immediately replaced by a Pt electrode, and a cathodic overpotential of 0.6 V from the open circuit potential (OCP) was applied under sonification to synthesize Au nanoparticles. Encouragingly, the prepared Au nanoparticles are active catalysts for the decomposition of 2000 ppm aldehyde in 40% (v/v%) ethanol aqueous solutions. After testing for 10 days, the aldehyde was decomposed by ca. 50% in alcohol solutions containing 25 ppm Au nanoparticles under slightly stirring. After testing for 10 days, the aldehyde was undetectable in Gin wines containing 60 ppm aldehyde by just adding 1 ppm Au nanoparticles under slightly stirring.