Environmentally Friendly Carbon-Preserving Recovery of Noble Metals From Supported Fuel Cell Catalysts

• Published in: ChemSusChem 2015-06, Vol.8 (11), p.1926-1934
• Main Authors: Latsuzbaia, R., Negro, E., Koper, G. J. M.
• Format: Article
• Language: English
• Subjects: Argon - chemistry; Carbon; Carbon - chemistry; Catalysis; Catalysts; Chloride ions; Chlorine - chemistry; Corrosion; Dissolution; Electric Power Supplies; Electrocatalysts; Electrochemical potential; electrochemistry; Electrodes; Electrolytic cells; Fuel cells; Green Chemistry Technology; Materials recovery; Membranes, Artificial; Nanoparticles; Noble metals; Oxygen - chemistry; Photoelectrons; platinum; Platinum - chemistry; Platinum - isolation & purification; Protons; Regeneration; Room temperature; supported catalysts; Surface Properties; Temperature
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201500019

The dissolution of noble‐metal catalysts under mild and carbon‐preserving conditions offers the possibility of in situ regeneration of the catalyst nanoparticles in fuel cells or other applications. Here, we report on the complete dissolution of the fuel cell catalyst, platinum nanoparticles, under very mild conditions at room temperature in 0.1 M HClO4 and 0.1 M HCl by electrochemical potential cycling between 0.5–1.1 V at a scan rate of 50 mV s−1. Dissolution rates as high as 22.5 μg cm−2 per cycle were achieved, which ensured a relatively short dissolution timescale of 3–5 h for a Pt loading of 0.35 mg cm−2 on carbon. The influence of chloride ions and oxygen in the electrolyte on the dissolution was investigated, and a dissolution mechanism is proposed on the basis of the experimental observations and available literature results. During the dissolution process, the corrosion of the carbon support was minimal, as observed by X‐ray photoelectron spectroscopy (XPS). Platinum recovery: Noble metal catalyst nanoparticles are typically used as electrocatalysts in fuel cells. The main problem of these catalysts is their degradation during operation, making their recovery after use an important issue. We present an in situ strategy to recover platinum from a fuel cell catalyst under mild conditions by electrochemical potential cycling, with minimal corrosion of the carbon support and possibility of the catalyst regeneration.