| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系 === 94 === The use of cleaner energy may allivate the considerable emission of air pollutants and CO2. The cleaner energy can be used as fuels for fuel cells. However, the fuel cells, due to aging/decay after use, will become wastes that need to be treated. The spent fuel cell electrodes contain precious metals deserved to be recycled/reused.
In this study, therefore, preliminary tests were conducted to recover the precious metals in spent fuel cell electrodes. Electrochemical analyses and electrolytic experiments were performed for the platinum chloride solutions with different Pt salts, Pt concentrations, pHs, and anions.
Results show that the redox peak currents of Pt chloride complexes and the electroactive areas of electro-deposited Pt increased with the increase of Pt concentrations (1–10 mM) in H2PtCl6 solutions after cyclic voltammetry (CV) scans. Similar results were found for the K2PtCl6 solutions with similar Pt concentrations. The 10 mM-Pt H2PtCl6 and K2PtCl6 solutions exhibited limiting currents around the potentials of -0.4 – -0.3 V and -0.5 – -0.2 V, respectively. The redox peak currents of Pt chloride complexes and the electroactive areas of deposited Pt decreased with increasing Cl- addition in H2PtCl6 solutions but this phenomenon was not found for the similar solutions with NO3- addition; moreover, similar results were found for the peak potential shift of Pt complex redox peaks for the Pt chloride solutions with the Cl- and NO3- addition in linear scan voltammetry (LSV) tests. For the constant potential (-0.5 V) electrolysis, the 10 mM H2PtCl6 and K2PtCl6 solutions displayed C/Co (Pt concentration with time/initial Pt concentration) values of 0.47 and 0.64, respectively at 180 min whereas for the constsnt current (0.1 A) electrolysis, the C/Co values of both the solutions reached about 0.09 with similar stable cell potentials around 5 V.
Keywords: Fuel cells , Spent electrodes , Noble/precious metals ,
Electrochemical characteristics
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